0001423689-20-000051 | 10-Q | XBRL Viewer

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Investment Securities (Summary Of Net Gain From Sale Of Agency Securities) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Cost of Sale of Fair Value Option Securities	$ (13,430)	$ (5,048)	$ (67,342)	$ (17,379)
Cost of Sale of Investment Securities	(13,430)	(5,048)	(68,775)	(18,084)
Proceeds from agency MBS sold			20,112	8,313
Net gain (loss) on sale of investment securities	346	89	993	281
Available-for-sale Securities [Member]
Agency MBS sold, at cost	0	0	(1,433)	(705)
Proceeds from agency MBS sold	0	0	1,473	696
Net gain (loss) on sale of investment securities		0		(9)
Gross gain on sale of investment securities	0	0	40	0
Gross loss on sale of investment securities	0	0	0	(9)
Securities Remeasured at Fair Value [Member]
Proceeds from agency MBS sold	13,776	5,137	68,295	17,669
Net gain (loss) on sale of investment securities		89		290
Gross gain on sale of investment securities	354	90	1,050	294
Gross loss on sale of investment securities	(8)	(1)	(97)	(4)
Securities (Assets) [Member]
Proceeds from agency MBS sold	13,776	5,137	69,768	18,365
Net gain (loss) on sale of investment securities	346	89	993	281
Gross gain on sale of investment securities	354	90	1,090	294
Gross loss on sale of investment securities	(8)	$ (1)	(97)	$ (13)
Cost and Proceeds of Investment Securities [Member] \| Available-for-sale Securities [Member]
Net gain (loss) on sale of investment securities	0		40
Cost and Proceeds of Investment Securities [Member] \| Securities Remeasured at Fair Value [Member]
Net gain (loss) on sale of investment securities	346		953
Gross Gain & Loss of Investment Securities [Member] \| Available-for-sale Securities [Member]
Net gain (loss) on sale of investment securities	0		40
Gross Gain & Loss of Investment Securities [Member] \| Securities Remeasured at Fair Value [Member]
Net gain (loss) on sale of investment securities	$ 346		$ 953

Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Assets:
Agency securities, at fair value (including pledged securities of $55,711 and $92,608, respectively)	$ 66,556,000	$ 98,516,000
Agency securities transferred to consolidated variable interest entities, at fair value (pledged securities)	323,000	371,000
Credit risk transfer securities, at fair value (including pledged securities of $413 and $309, respectively)	653,000	976,000
Non-Agency securities, at fair value (including pledged securities of $455 and $0, respectively)	512,000	579,000
U.S. Treasury securities, at fair value (including pledged securities of $0 and $97, respectively)	0	97,000
Cash and cash equivalents	857,000	831,000
Restricted cash	1,557,000	451,000
Derivative assets, at fair value	130,000	190,000
Receivable for investment securities sold (including pledged securities of $10 and $0, respectively)	10,000	0
Receivable under reverse repurchase agreements	8,625,000	10,181,000
Goodwill and other intangible assets, net	526,000	526,000
Other assets	219,000	364,000
Total assets	79,968,000	113,082,000
Liabilities:
Repurchase Agreements	54,566,000	89,182,000
Debt of consolidated variable interest entities, at fair value	192,000	228,000
Payable for investment securities purchased	5,887,000	2,554,000
Derivative liabilities, at fair value	13,000	6,000
Dividends payable	90,000	104,000
Accounts payable and other liabilities	128,000	424,000
Total liabilities	69,248,000	102,041,000
Stockholders' equity:
Preferred Stock - aggregate liquidation preference of $1,538 and $963, respectively	1,489,000	932,000
Common stock - $0.01 par value; 1,500 and 900 shares authorized, respectively; 545.2 and 540.9 shares issued and outstanding, respectively	5,000	5,000
Additional paid-in capital	14,053,000	13,893,000
Retained deficit	(5,661,000)	(3,886,000)
Accumulated other comprehensive income	834,000	97,000
Total stockholders' equity	10,720,000	11,041,000
Total liabilities and stockholders' equity	79,968,000	113,082,000
Security Owned and Pledged as Collateral, Fair Value	56,014,000	92,547,000
Security Owned and Pledged as Collateral, Fair Value	56,014,000	92,547,000
Agency Securities [Member]
Stockholders' equity:
Security Owned and Pledged as Collateral, Fair Value	55,711,000	92,608,000
Security Owned and Pledged as Collateral, Fair Value	$ 55,711,000	$ 92,608,000

Consolidated Statement of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings (Accumulated Deficit) [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Balance, value at Dec. 31, 2018	$ 9,906,000	$ 484,000	$ 5,000	$ 13,793,000	$ (3,433,000)	$ (943,000)
Balance, Common Stock, shares at Dec. 31, 2018			536,300
Net income (loss)	(183,000)				(183,000)
Other comprehensive income (loss):
Unrealized Gains and (Losses), Net	$ 1,025,000					1,025,000
Shares Issued, Shares, Share-based Payment Arrangement, before Forfeiture	100
APIC, Share-based Payment Arrangement, Recognition and Exercise	$ 8,000			8,000
Stock Repurchased During Period, Shares			(6,900)
Proceeds from Issuance of Preferred Stock and Preference Stock	227,000
Stock Issued During Period, Shares, New Issues			11,400
Stock Issued During Period, Value, New Issues	190,000			190,000
Repurchase of common stock				(103,000)
Payments for Repurchase of Common Stock	103,000
Preferred dividends declared	(36,000)				(36,000)
Common dividends declared	(821,000)				(821,000)
Balance, value at Sep. 30, 2019	10,213,000	711,000	$ 5,000	13,888,000	(4,473,000)	82,000
Balance, Common Stock, shares at Sep. 30, 2019			540,900
Balance, value at Jun. 30, 2019	10,346,000	711,000	$ 5,000	13,988,000	(4,194,000)	(164,000)
Balance, Common Stock, shares at Jun. 30, 2019			547,800
Net income (loss)	(4,000)				(4,000)
Other comprehensive income (loss):
Unrealized Gains and (Losses), Net	$ 246,000					246,000
Shares Issued, Shares, Share-based Payment Arrangement, before Forfeiture	0
APIC, Share-based Payment Arrangement, Recognition and Exercise	$ 3,000			3,000
Stock Issued During Period, Value, New Issues	(103,000)
Preferred dividends declared	(13,000)				(13,000)
Common dividends declared	(262,000)				(262,000)
Balance, value at Sep. 30, 2019	10,213,000	711,000	$ 5,000	13,888,000	(4,473,000)	82,000
Balance, Common Stock, shares at Sep. 30, 2019			540,900
Balance, value at Dec. 31, 2019	$ 11,041,000	932,000	$ 5,000	13,893,000	(3,886,000)	97,000
Balance, Common Stock, shares at Dec. 31, 2019	540,900		540,900
Net income (loss)	$ (1,041,000)				(1,041,000)
Other comprehensive income (loss):
Unrealized Gains and (Losses), Net	$ 737,000					737,000
Shares Issued, Shares, Share-based Payment Arrangement, before Forfeiture	100
APIC, Share-based Payment Arrangement, Recognition and Exercise	$ 12,000			12,000
Stock Repurchased During Period, Shares	(22,500)
Proceeds from Issuance of Preferred Stock and Preference Stock	$ 557,000
Stock Issued During Period, Shares, New Issues	26,700		26,700
Stock Issued During Period, Value, New Issues	$ 439,000		$ 1,000	438,000
Repurchase of common stock	(291,000)		(1,000)	(290,000)
Payments for Repurchase of Common Stock	291,000
Preferred dividends declared	(71,000)				(71,000)
Common dividends declared	(663,000)				(663,000)
Balance, value at Sep. 30, 2020	10,720,000	1,489,000	$ 5,000	14,053,000	(5,661,000)	834,000
Balance, Common Stock, shares at Sep. 30, 2020			545,200
Balance, value at Jun. 30, 2020	10,350,000	1,489,000	$ 6,000	14,191,000	(6,100,000)	764,000
Balance, Common Stock, shares at Jun. 30, 2020			555,500
Net income (loss)	662,000				662,000
Other comprehensive income (loss):
Unrealized Gains and (Losses), Net	70,000					70,000
APIC, Share-based Payment Arrangement, Recognition and Exercise	$ 5,000			5,000
Stock Repurchased During Period, Shares	(10,300)
Repurchase of common stock	$ (144,000)		$ (1,000)	(143,000)
Preferred dividends declared	(25,000)				(25,000)
Common dividends declared	(198,000)				(198,000)
Balance, value at Sep. 30, 2020	$ 10,720,000	$ 1,489,000	$ 5,000	$ 14,053,000	$ (5,661,000)	$ 834,000
Balance, Common Stock, shares at Sep. 30, 2020			545,200

Pledged Assets (Offsetting Assets and Liabilities) (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Offsetting Assets and Liabilities [Line Items]
Collateral Received	$ (3,150)
Assets [Member]
Offsetting Assets and Liabilities [Line Items]
Gross Amounts of Recognized Assets	8,755	$ 10,357
Gross Amount Offset in the Consolidated Balance Sheets	0
Net Amounts of Assets Presented in the Consolidated Balance Sheets	8,755	10,357
Financial Instruments	(5,471)	(9,858)
Collateral Received		(445)
Net Amount	134	54
Assets [Member] \| ERROR in label resolution.
Offsetting Assets and Liabilities [Line Items]
Gross Amounts of Recognized Assets	46	147
Net Amounts of Assets Presented in the Consolidated Balance Sheets	46	147
Financial Instruments	0	(2)
Collateral Received	(3)	(116)
Net Amount	43	29
Assets [Member] \| TBA and Forward Settling Agency Securities [Member]
Offsetting Assets and Liabilities [Line Items]
Gross Amounts of Recognized Assets	84	29
Net Amounts of Assets Presented in the Consolidated Balance Sheets	84	29
Financial Instruments	(8)	(4)
Net Amount	76	25
Assets [Member] \| Reverse Repurchase Agreements [Member]
Offsetting Assets and Liabilities [Line Items]
Net Amount	15	0
Liability [Member]
Offsetting Assets and Liabilities [Line Items]
Gross Amounts of Recognized Assets	54,574	89,188
Gross Amount Offset in the Consolidated Balance Sheets	0
Net Amounts of Assets Presented in the Consolidated Balance Sheets	54,574	89,188
Financial Instruments	(5,471)	(9,858)
Collateral Received	(49,103)	(79,330)
Net Amount	0
Liability [Member] \| Repurchase Agreements [Member]
Offsetting Assets and Liabilities [Line Items]
Net Amount	0	0
Liability [Member] \| ERROR in label resolution.
Offsetting Assets and Liabilities [Line Items]
Gross Amounts of Recognized Assets	0	2
Net Amounts of Assets Presented in the Consolidated Balance Sheets	0	2
Financial Instruments	0	(2)
Collateral Received	0	0
Net Amount	0	0
Liability [Member] \| TBA and Forward Settling Agency Securities [Member]
Offsetting Assets and Liabilities [Line Items]
Gross Amounts of Recognized Assets	8	4
Net Amounts of Assets Presented in the Consolidated Balance Sheets	8	4
Financial Instruments	(8)	(4)
Collateral Received	0	0
Net Amount	0	0
Reverse Repurchase Agreements [Member] \| Assets [Member]
Offsetting Assets and Liabilities [Line Items]
Gross Amounts of Recognized Assets	8,625	10,181
Gross Amount Offset in the Consolidated Balance Sheets	0
Net Amounts of Assets Presented in the Consolidated Balance Sheets	8,625	10,181
Financial Instruments	(5,463)	(9,852)
Collateral Received	(3,147)	(329)
Repurchase Agreements [Member] \| Liability [Member]
Offsetting Assets and Liabilities [Line Items]
Gross Amounts of Recognized Assets	54,566	89,182
Gross Amount Offset in the Consolidated Balance Sheets	0
Net Amounts of Assets Presented in the Consolidated Balance Sheets	54,566	89,182
Financial Instruments	(5,463)	(9,852)
Collateral Received	$ (49,103)	$ (79,330)

Organization	9 Months Ended
Organization	Sep. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization	Organization We were organized in Delaware on January 7, 2008 and commenced operations on May 20, 2008 following the completion of our initial public offering. Our common stock is traded on The Nasdaq Global Select Market under the symbol "AGNC." We are internally managed, and our principal objective is to provide our stockholders with attractive risk-adjusted returns through a combination of monthly dividends and tangible net book value accretion. We generate income from the interest earned on our investments, net of associated borrowing and hedging costs, and net realized gains and losses on our investment and hedging activities. We operate to qualify to be taxed as a real estate investment trust ("REIT") under the Internal Revenue Code of 1986, as amended (the "Internal Revenue Code"). As a REIT, we are required to distribute annually 90% of our taxable income, and we will generally not be subject to U.S. federal or state corporate income tax to the extent that we distribute our annual taxable income to our stockholders on a timely basis. It is our intention to distribute 100% of our taxable income, after application of available tax attributes, within the limits prescribed by the Internal Revenue Code, which may extend into the subsequent tax year. We invest primarily in Agency residential mortgage-backed securities ("Agency RMBS") for which the principal and interest payments are guaranteed by a U.S. Government-sponsored enterprise ("GSE") or a U.S. Government agency. We also invest in other types of mortgage and mortgage-related securities, such as credit risk transfer ("CRT") securities and non-Agency residential and commercial mortgage-backed securities ("non-Agency RMBS" and "CMBS," respectively), where repayment of principal and interest is not guaranteed by a GSE or U.S. Government agency, and in other investments in, or related to, the housing, mortgage or real estate markets. We fund our investments primarily through borrowings structured as repurchase agreements.

Pledged Assets (Assets Pledged as Collateral) (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Offsetting Assets and Liabilities [Line Items]
Pledged Financial Instruments, Not Separately Reported, Mortgage-Related Securities Available-for-sale or Held-for-investment	$ 56,014	$ 92,547
Retained Interests in Consolidated VIE's Pledged as Collateral Under Repurchase Agreements	131	144
Accrued interest on pledged securities	161	270
Restricted cash	1,557	451
Total Fair Value of Securities Pledged and Accrued Interest	58,961
Total Fair Value Of Agency Securities Pledged And Accrued Interest		94,634
Repurchase Agreements [Member]
Offsetting Assets and Liabilities [Line Items]
Pledged Financial Instruments, Not Separately Reported, Mortgage-Related Securities Available-for-sale or Held-for-investment	55,136	92,142
Derivative [Member]
Offsetting Assets and Liabilities [Line Items]
Pledged Financial Instruments, Not Separately Reported, Mortgage-Related Securities Available-for-sale or Held-for-investment	405	404
Accrued interest on pledged securities		1
Restricted cash	909	340
Total Fair Value of Securities Pledged and Accrued Interest	1,315
Total Fair Value Of Agency Securities Pledged And Accrued Interest		745
Repurchase Agreements [Member]
Offsetting Assets and Liabilities [Line Items]
Accrued interest on pledged securities	158	267
Total Fair Value of Securities Pledged and Accrued Interest	57,020
Total Fair Value Of Agency Securities Pledged And Accrued Interest		93,282
Variable Interest Entity, Primary Beneficiary [Member]
Offsetting Assets and Liabilities [Line Items]
Pledged Financial Instruments, Not Separately Reported, Mortgage-Related Securities Available-for-sale or Held-for-investment	323	371
Accrued interest on pledged securities	1	1
Total Fair Value of Securities Pledged and Accrued Interest	324
Total Fair Value Of Agency Securities Pledged And Accrued Interest		372
Under Prime Broker Agreements [Member]
Offsetting Assets and Liabilities [Line Items]
Pledged Financial Instruments, Not Separately Reported, Mortgage-Related Securities Available-for-sale or Held-for-investment	301	206
Accrued interest on pledged securities	1	1
Total Fair Value of Securities Pledged and Accrued Interest	302
Total Fair Value Of Agency Securities Pledged And Accrued Interest		235
Includes Sold But Not Yet Settled Securities [Member]
Offsetting Assets and Liabilities [Line Items]
Pledged Financial Instruments, Not Separately Reported, Mortgage-Related Securities Available-for-sale or Held-for-investment	56,165	93,123
Credit Risk Transfer Securities [Member]
Offsetting Assets and Liabilities [Line Items]
Pledged Financial Instruments, Not Separately Reported, Mortgage-Related Securities Available-for-sale or Held-for-investment	423	309
Credit Risk Transfer Securities [Member] \| Repurchase Agreements [Member]
Offsetting Assets and Liabilities [Line Items]
Pledged Financial Instruments, Not Separately Reported, Mortgage-Related Securities Available-for-sale or Held-for-investment	423	309
Credit Risk Transfer Securities [Member] \| Derivative [Member]
Offsetting Assets and Liabilities [Line Items]
Pledged Financial Instruments, Not Separately Reported, Mortgage-Related Securities Available-for-sale or Held-for-investment	0	0
Non-Agency [Member]
Offsetting Assets and Liabilities [Line Items]
Pledged Financial Instruments, Not Separately Reported, Mortgage-Related Securities Available-for-sale or Held-for-investment	455
Non-Agency [Member] \| Repurchase Agreements [Member]
Offsetting Assets and Liabilities [Line Items]
Pledged Financial Instruments, Not Separately Reported, Mortgage-Related Securities Available-for-sale or Held-for-investment	455
Non-Agency [Member] \| Derivative [Member]
Offsetting Assets and Liabilities [Line Items]
Pledged Financial Instruments, Not Separately Reported, Mortgage-Related Securities Available-for-sale or Held-for-investment	0
US Treasury Securities [Member]
Offsetting Assets and Liabilities [Line Items]
Pledged Financial Instruments, Not Separately Reported, Mortgage-Related Securities Available-for-sale or Held-for-investment	200	481
US Treasury Securities [Member] \| Under Prime Broker Agreements [Member]
Offsetting Assets and Liabilities [Line Items]
Pledged Financial Instruments, Not Separately Reported, Mortgage-Related Securities Available-for-sale or Held-for-investment	0	28
US Treasury Securities [Member] \| Repurchase Agreements [Member]
Offsetting Assets and Liabilities [Line Items]
Pledged Financial Instruments, Not Separately Reported, Mortgage-Related Securities Available-for-sale or Held-for-investment	200	453
US Treasury Securities [Member] \| Derivative [Member]
Offsetting Assets and Liabilities [Line Items]
Pledged Financial Instruments, Not Separately Reported, Mortgage-Related Securities Available-for-sale or Held-for-investment	0	0
Derivative [Member]
Offsetting Assets and Liabilities [Line Items]
Accrued interest on pledged securities	1
Repurchase Agreements [Member]
Offsetting Assets and Liabilities [Line Items]
Restricted cash	648	111
Under Prime Broker Agreements [Member]
Offsetting Assets and Liabilities [Line Items]
Restricted cash	0	0
Excluding Cash Received [Member]
Offsetting Assets and Liabilities [Line Items]
Restricted cash	$ 1,557	$ 451

Net Income (Loss) Per Common Share (Notes)

9 Months Ended

Sep. 30, 2020

Net Income (Loss) Per Common Share [Abstract]

Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]


	Three Months Ended September 30,				Nine Months Ended September 30,
	2020		2019		2020		2019
Weighted average number of common shares issued and outstanding	552.1		546.0		552.9		539.9
Weighted average number of fully vested restricted stock units outstanding	1.1		0.4		0.9		0.4
Weighted average number of common shares outstanding - basic	553.2		546.4		553.8		540.3
Weighted average number of dilutive unvested restricted stock units outstanding	1.1		—		—		—
Weighted average number of common shares outstanding - diluted	554.3		546.4		553.8		540.3
Net income (loss) available (attributable) to common stockholders	$	637	$	(17)	$	(1,112)	$	(219)
Net income (loss) per common share - basic	$	1.15	$	(0.03)	$	(2.01)	$	(0.41)
Net income (loss) per common share - diluted	$	1.15	$	(0.03)	$	(2.01)	$	(0.41)

Earnings Per Share [Text Block]

Net Income (Loss) Per Common Share Basic net income (loss) per common share is computed by dividing (i) net income (loss) available (attributable) to common stockholders by (ii) the sum of our weighted-average number of common shares outstanding and the weighted-average number of vested but not yet issued time and performance-based restricted stock units ("RSUs") outstanding for the period granted under our long-term incentive program to employees and non-employee Board of Directors. Diluted net income (loss) per common share assumes the issuance of all potential common stock equivalents unless the effect is to reduce a loss or increase the income per common share. Our potential common stock equivalents consist of unvested time and performance-based RSUs. The following table presents the computations of basic and diluted net income (loss) per common share for the periods indicated (shares and dollars in millions):


	Three Months Ended September 30,				Nine Months Ended September 30,
	2020		2019		2020		2019
Weighted average number of common shares issued and outstanding	552.1		546.0		552.9		539.9
Weighted average number of fully vested restricted stock units outstanding	1.1		0.4		0.9		0.4
Weighted average number of common shares outstanding - basic	553.2		546.4		553.8		540.3
Weighted average number of dilutive unvested restricted stock units outstanding	1.1		—		—		—
Weighted average number of common shares outstanding - diluted	554.3		546.4		553.8		540.3
Net income (loss) available (attributable) to common stockholders	$	637	$	(17)	$	(1,112)	$	(219)
Net income (loss) per common share - basic	$	1.15	$	(0.03)	$	(2.01)	$	(0.41)
Net income (loss) per common share - diluted	$	1.15	$	(0.03)	$	(2.01)	$	(0.41)

For the nine months ended September 30, 2020 and for the three and nine months ended September 30, 2019, 1.0 million, 0.7 million and 0.6 million, respectively, of potentially dilutive unvested time and performance based RSUs outstanding were excluded from the computation of diluted net income (loss) per common share because to do so would have been anti-dilutive for the period.

Fair Value Measurements (Details) - USD ($) $ in Millions	9 Months Ended
Fair Value Measurements (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Future [Member] \| Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| US Treasury Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
TBA securities	$ 0	$ 14
Derivative Liability	5	0
Interest Rate Swaption [Member] \| Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swaps	5	126
Interest Rate Swap [Member] \| Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swaps	41	21
Interest Rate Swap [Member] \| Derivative liabilities, at fair value [Member] \| Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Interest Rate Swap [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swaps	0	2
Purchases Of TBAs And Forward Settling Agency Securities [Member] \| Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| TBA and Forward Settling Agency Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
TBA securities	(84)	(29)
Securities Sold under Agreements to Repurchase	$ 54,566	89,182
Transfers between hierarchy levels	no
Agency securities	$ 66,556	98,516
Non-Agency Securities, at Fair Value	512	579
Financial Instruments, Owned, Other, at Fair Value	653	976
U.S. Treasury securities	0	97
TBA securities	(130)	(190)
Derivative Liability	13	6
Debt of consolidated variable interest entities, at fair value	192	228
Interest rate swaps	130	190
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	0	111
Total liabilities	8,377	9,543
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	68,174	100,618
Total liabilities	200	234
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Sale Of TBA And Forward Settling Agency Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liability	$ 8	$ 4

Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2020

Fair Value Disclosures [Abstract]

Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis

The following table provides a summary of our assets and liabilities that are measured at fair value on a recurring basis, as of September 30, 2020 and December 31, 2019, based on their categorization within the valuation hierarchy (in millions). There were no transfers between valuation hierarchy levels during the periods presented.


	September 30, 2020						December 31, 2019
	Level 1		Level 2		Level 3		Level 1		Level 2		Level 3
Assets:
Agency securities	$	—	$	66,556	$	—	$	—	$	98,516	$	—
Agency securities transferred to consolidated VIEs	—		323		—		—		371		—
Credit risk transfer securities	—		653		—		—		976		—
Non-Agency securities	—		512		—		—		579		—
U.S. Treasury securities	—		—		—		97		—		—
Interest rate swaps	—		41		—		—		21		—
Swaptions	—		5		—		—		126		—
TBA securities	—		84		—		—		29		—
U.S. Treasury futures	—		—		—		14		—		—
Total	$	—	$	68,174	$	—	$	111	$	100,618	$	—
Liabilities:
Debt of consolidated VIEs	$	—	$	192	$	—	$	—	$	228	$	—
Obligation to return U.S. Treasury securities borrowed under reverse repurchase agreements	8,372		—		—		9,543		—		—
Interest rate swaps	—		—		—		—		2		—
TBA securities	—		8		—		—		4		—
U.S. Treasury futures	5		—		—		—		—		—
Total	$	8,377	$	200	$	—	$	9,543	$	234	$	—

Derivative and Other Hedging Instruments (TBA Securities by Coupon and Issuer) (Details) - TBA and Forward Settling Agency Securities [Member] - USD ($) $ in Millions	Sep. 30, 2020	Jun. 30, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Dec. 31, 2018
Derivative [Line Items]
Derivative, Notional Amount	$ 28,521	$ 19,760	$ 7,322	$ 1,967	$ 11,043	$ 7,152
Cost Basis	29,460		7,404
Net long TBA position, at fair value	(29,536)		(7,429)
TBA, net carrying value	76		25
30 Year Maturity [Member]
Derivative [Line Items]
Derivative, Notional Amount	17,427		5,142
Cost Basis	18,039		5,182
Net long TBA position, at fair value	(18,080)		(5,203)
TBA, net carrying value	41		21
30 Year Maturity [Member] \| 2.0% Coupon [Member]
Derivative [Line Items]
Derivative, Notional Amount	11,375		0
Cost Basis	11,694		0
Net long TBA position, at fair value	(11,736)		0
TBA, net carrying value	42		0
30 Year Maturity [Member] \| 2.5% Coupon [Member]
Derivative [Line Items]
Derivative, Notional Amount	5,489		0
Cost Basis	5,752		0
Net long TBA position, at fair value	(5,753)		0
TBA, net carrying value	1		0
30 Year Maturity [Member] \| 3.0% Coupon [Member]
Derivative [Line Items]
Derivative, Notional Amount	395		5,008
Cost Basis	415		5,052
Net long TBA position, at fair value	(413)		(5,073)
TBA, net carrying value	(2)		21
30 Year Maturity [Member] \| 3.5% Coupon [Member]
Derivative [Line Items]
Derivative, Notional Amount	168		1,226
Cost Basis	178		1,259
Net long TBA position, at fair value	(178)		(1,261)
TBA, net carrying value	0		2
30 Year Maturity [Member] \| 4.0% Coupon [Member]
Derivative [Line Items]
Derivative, Notional Amount	0
Cost Basis	0		1,565
Net long TBA position, at fair value	0		(1,568)
TBA, net carrying value	0		(3)
30 Year Maturity [Member] \| 4.5% Coupon [Member]
Derivative [Line Items]
Derivative, Notional Amount	0		415
Cost Basis	0		436
Net long TBA position, at fair value	0		(437)
TBA, net carrying value	0		1
30 Year Maturity [Member] \| Short [Member] \| 4.0% Coupon [Member]
Derivative [Line Items]
Derivative, Notional Amount			1,507
15 Year Maturity [Member]
Derivative [Line Items]
Derivative, Notional Amount	11,094		2,180
Cost Basis	11,421		2,222
Net long TBA position, at fair value	(11,456)		(2,226)
TBA, net carrying value	35		4
15 Year Maturity [Member] \| 2.0% Coupon [Member]
Derivative [Line Items]
Derivative, Notional Amount	10,228		0
Cost Basis	10,514		0
Net long TBA position, at fair value	(10,552)		0
TBA, net carrying value	38		0
15 Year Maturity [Member] \| 2.5% Coupon [Member]
Derivative [Line Items]
Derivative, Notional Amount	866		805
Cost Basis	907		811
Net long TBA position, at fair value	(904)		(812)
TBA, net carrying value	(3)		1
15 Year Maturity [Member] \| 3.0% Coupon [Member]
Derivative [Line Items]
Derivative, Notional Amount	0		1,059
Cost Basis	0		1,083
Net long TBA position, at fair value	0		(1,086)
TBA, net carrying value	0		3
15 Year Maturity [Member] \| 3.5% Coupon [Member]
Derivative [Line Items]
Derivative, Notional Amount	0		241
Cost Basis	0		250
Net long TBA position, at fair value	0		(250)
TBA, net carrying value	0		0
15 Year Maturity [Member] \| 4.0% Coupon [Member]
Derivative [Line Items]
Derivative, Notional Amount	0		75
Cost Basis	0		78
Net long TBA position, at fair value	0		(78)
TBA, net carrying value	$ 0		$ 0

Pledged Assets (Tables)

9 Months Ended

Sep. 30, 2020

Pledged Assets [Abstract]

Schedule of Securities and Cash Pledged as Collateral from Counterparties [Table Text Block]

As of September 30, 2020 and December 31, 2019, we had assets pledged to us from counterparties as collateral under our reverse repurchase and derivative agreements summarized in the tables below (in millions).


	September 30, 2020								December 31, 2019
Assets Pledged to AGNC	Reverse Repurchase Agreements		Derivative Agreements		Repurchase Agreements		Total		Reverse Repurchase Agreements		Derivative Agreements		Repurchase Agreements		Total
U.S. Treasury securities - fair value 1	$	8,579	$	—	$	211	$	8,790	$	10,099	$	—	$	1	$	10,100
Cash	—		5		4		9		—		116		—		116
Total	$	8,579	$	5	$	215	$	8,799	$	10,099	$	116	$	1	$	10,216

________________________________

1.As of September 30, 2020 and December 31, 2019, $200 million and $357 million, respectively, of U.S. Treasury securities received from counterparties were repledged as collateral and $8.4 billion and $9.5 billion, respectively, were used to cover short sales of U.S. Treasury securities.

Schedule of Financial Instruments Owned and Pledged as Collateral

The following tables summarize our assets pledged as collateral under our funding, derivative and brokerage and clearing agreements by type, including securities pledged related to securities sold but not yet settled, as of September 30, 2020 and December 31, 2019 (in millions):


	September 30, 2020
Assets Pledged to Counterparties 1	Repurchase Agreements 2		Debt of Consolidated VIEs		Derivative Agreements		Brokerage and Clearing Agreements 3		Total
Agency RMBS - fair value	$	55,136	$	323	$	405	$	301	$	56,165
CRT - fair value	423		—		—		—		423
Non-Agency - fair value	455		—		—		—		455
U.S. Treasury securities - fair value	200		—		—		—		200
Accrued interest on pledged securities	158		1		1		1		161
Restricted cash	648		—		909		—		1,557
Total	$	57,020	$	324	$	1,315	$	302	$	58,961


	December 31, 2019
Assets Pledged to Counterparties 1	Repurchase Agreements 2		Debt of Consolidated VIEs		Derivative Agreements		Brokerage and Clearing Agreements 3		Total
Agency RMBS - fair value	$	92,142	$	371	$	404	$	206	$	93,123
CRT - fair value	309		—		—		—		309
U.S. Treasury securities - fair value	453		—		—		28		481
Accrued interest on pledged securities	267		1		1		1		270
Restricted cash	111		—		340		—		451
Total	$	93,282	$	372	$	745	$	235	$	94,634

________________________________

1.Includes repledged assets received as collateral from counterparties and securities sold but not yet settled.

2.Includes $131 million and $144 million of retained interests in our consolidated VIEs pledged as collateral under repurchase agreements as of September 30, 2020 and December 31, 2019, respectively.

3.Includes margin for TBAs cleared through prime brokers and other clearing deposits.

Schedules Of Securities Pledged As Collateral Under Repurchase Agreement

The following table summarizes our securities pledged as collateral under our repurchase agreements by the remaining maturity of our borrowings, including securities pledged related to sold but not yet settled securities, as of September 30, 2020 and December 31, 2019 (in millions). For the corresponding borrowings associated with the following amounts and the interest rates thereon, refer to Note 5.


	September 30, 2020						December 31, 2019
Securities Pledged by Remaining Maturity of Repurchase Agreements 1,2	Fair Value of Pledged Securities		Amortized Cost of Pledged Securities		Accrued Interest on Pledged Securities		Fair Value of Pledged Securities		Amortized Cost of Pledged Securities		Accrued Interest on Pledged Securities
≤ 30 days	$	28,729	$	27,243	$	82	$	56,990	$	55,951	$	167
> 30 and ≤ 60 days	8,666		8,214		24		14,410		14,114		42
> 60 and ≤ 90 days	4,568		4,378		12		7,637		7,536		20
> 90 days	14,051		13,380		40		13,510		13,286		38
Total	$	56,014	$	53,215	$	158	$	92,547	$	90,887	$	267

________________________________

1.Includes $131 million and $144 million of retained interests in our consolidated VIEs pledged as collateral under repurchase agreements as of September 30, 2020 and December 31, 2019, respectively.

2.Excludes $200 million and $357 million of repledged U.S. Treasury securities received as collateral from counterparties as of September 30, 2020 and December 31, 2019, respectively.

Offsetting Assets and Liabilities

The following tables present information about our assets and liabilities that are subject to master netting arrangements and can potentially be offset on our consolidated balance sheets as of September 30, 2020 and December 31, 2019 (in millions):


	Offsetting of Financial and Derivative Assets
	Gross Amounts of Recognized Assets		Gross Amounts Offset in the Consolidated Balance Sheets		Net Amounts of Assets Presented in the Consolidated Balance Sheets		Gross Amounts Not Offset in the Consolidated Balance Sheets				Net Amount
							Financial Instruments		Collateral Received 2
September 30, 2020
Interest rate swap and swaption agreements, at fair value 1	$	46	$	—	$	46	$	—	$	(3)	$	43
TBA securities, at fair value	84		—		84		(8)		—		76
Receivable under reverse repurchase agreements	8,625		—		8,625		(5,463)		(3,147)		15
Total	$	8,755	$	—	$	8,755	$	(5,471)	$	(3,150)	$	134

December 31, 2019
Interest rate swap and swaption agreements, at fair value 1	$	147	$	—	$	147	$	(2)	$	(116)	$	29
TBA securities, at fair value	29		—		29		(4)		—		25
Receivable under reverse repurchase agreements	10,181		—		10,181		(9,852)		(329)		—
Total	$	10,357	$	—	$	10,357	$	(9,858)	$	(445)	$	54

Offsetting Liabilities


	Offsetting of Financial and Derivative Liabilities
	Gross Amounts of Recognized Liabilities		Gross Amounts Offset in the Consolidated Balance Sheets		Net Amounts of Liabilities Presented in the Consolidated Balance Sheets		Gross Amounts Not Offset in the Consolidated Balance Sheets				Net Amount
							Financial Instruments		Collateral Pledged 2
September 30, 2020
Interest rate swap agreements, at fair value 1	$	—	$	—	$	—	$	—	$	—	$	—
TBA securities, at fair value	8		—		8		(8)		—		—
Repurchase agreements	54,566		—		54,566		(5,463)		(49,103)		—
Total	$	54,574	$	—	$	54,574	$	(5,471)	$	(49,103)	$	—

December 31, 2019
Interest rate swap agreements, at fair value 1	$	2	$	—	$	2	$	(2)	$	—	$	—
TBA securities, at fair value	4		—		4		(4)		—		—
Repurchase agreements	89,182		—		89,182		(9,852)		(79,330)		—
Total	$	89,188	$	—	$	89,188	$	(9,858)	$	(79,330)	$	—

________________________________

1.Reported under derivative assets / liabilities, at fair value in the accompanying consolidated balance sheets. Refer to Note 6 for a reconciliation of derivative assets / liabilities, at fair value to their sub-components.

2.Includes cash and securities pledged / received as collateral, at fair value. Amounts include repledged collateral. Amounts presented are limited to collateral pledged sufficient to reduce the net amount to zero for individual counterparties, as applicable.

Pledged Assets (Securities Pledged as Collateral) (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Offsetting Assets and Liabilities [Line Items]
Retained Interests in Consolidated VIE's Pledged as Collateral Under Repo	$ 131	$ 144
Security Owned and Pledged as Collateral, Fair Value	56,014	92,547
Agency Securities Pledged As Collateral Amortized Cost	53,215	90,887
Agency Securities Pledged As Collateral Accrued Interest	158	267
Maturity Less than 30 Days [Member]
Offsetting Assets and Liabilities [Line Items]
Security Owned and Pledged as Collateral, Fair Value	28,729	56,990
Agency Securities Pledged As Collateral Amortized Cost	27,243	55,951
Agency Securities Pledged As Collateral Accrued Interest	82	167
Maturity 31 To 59 Days [Member]
Offsetting Assets and Liabilities [Line Items]
Security Owned and Pledged as Collateral, Fair Value	8,666	14,410
Agency Securities Pledged As Collateral Amortized Cost	8,214	14,114
Agency Securities Pledged As Collateral Accrued Interest	24	42
Maturity 60 To 90 Days [Member]
Offsetting Assets and Liabilities [Line Items]
Security Owned and Pledged as Collateral, Fair Value	4,568	7,637
Agency Securities Pledged As Collateral Amortized Cost	4,378	7,536
Agency Securities Pledged As Collateral Accrued Interest	12	20
Maturity over 90 days [Member]
Offsetting Assets and Liabilities [Line Items]
Security Owned and Pledged as Collateral, Fair Value	14,051	13,510
Agency Securities Pledged As Collateral Amortized Cost	13,380	13,286
Agency Securities Pledged As Collateral Accrued Interest	40	38
Repurchase Agreements [Member]
Offsetting Assets and Liabilities [Line Items]
Security Owned and Pledged as Collateral, Fair Value	55,136	92,142
Derivative [Member]
Offsetting Assets and Liabilities [Line Items]
Security Owned and Pledged as Collateral, Fair Value	405	404
Credit Risk Transfer Securities [Member]
Offsetting Assets and Liabilities [Line Items]
Security Owned and Pledged as Collateral, Fair Value	423	309
Credit Risk Transfer Securities [Member] \| Repurchase Agreements [Member]
Offsetting Assets and Liabilities [Line Items]
Security Owned and Pledged as Collateral, Fair Value	423	309
Credit Risk Transfer Securities [Member] \| Derivative [Member]
Offsetting Assets and Liabilities [Line Items]
Security Owned and Pledged as Collateral, Fair Value	0	0
US Treasury Securities [Member]
Offsetting Assets and Liabilities [Line Items]
Security Owned and Pledged as Collateral, Fair Value	200	481
Securities Received as Collateral, Amount Repledged and Sold	200	357
US Treasury Securities [Member] \| Repurchase Agreements [Member]
Offsetting Assets and Liabilities [Line Items]
Security Owned and Pledged as Collateral, Fair Value	200	453
US Treasury Securities [Member] \| Derivative [Member]
Offsetting Assets and Liabilities [Line Items]
Security Owned and Pledged as Collateral, Fair Value	0	$ 0
Non-Agency [Member]
Offsetting Assets and Liabilities [Line Items]
Security Owned and Pledged as Collateral, Fair Value	455
Non-Agency [Member] \| Repurchase Agreements [Member]
Offsetting Assets and Liabilities [Line Items]
Security Owned and Pledged as Collateral, Fair Value	455
Non-Agency [Member] \| Derivative [Member]
Offsetting Assets and Liabilities [Line Items]
Security Owned and Pledged as Collateral, Fair Value	$ 0

Stockholders' Equity (Preferred Stock) (Details) - USD ($) $ / shares in Units, $ in Thousands			1 Months Ended	9 Months Ended
	Feb. 11, 2020	Oct. 03, 2019	May 31, 2014	Sep. 30, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Preferred Stock E, Value, Issued		$ 390,000
Preferred Stock E, Liquidation Preference, Value		$ 403,000
Preferred Stock F, Value, Issued	$ 557,000
Preferred Stock D, Value, Issued				$ 227,000
Preferred Stock D, Liquidation Preference, Value				235,000
Preferred Stock C, Value, Issued				315,000
Preferred Stock C, Liquidation Preference, Value				325,000
Preferred Stock, Value, Issued				1,489,000	$ 932,000
Preferred Stock, Liquidation Preference, Value				$ 1,538,000	$ 963,000
Preferred Stock, Shares Authorized				10,000,000.0
Series B Preferred Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Preferred Stock, Percent Interest Per Share			0.10%
Series C Preferred Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Preferred Stock, Capital Shares Reserved for Future Issuance				13,800
Preferred Stock, Dividend Rate, Percentage				7.00%
Preferred Stock Dividend Payment Rate Variable Rate Spread				5.111%
Preferred Stock, Liquidation Preference Per Share				$ 25.00
Preferred Stock, Shares Issued				13,000
Series D Preferred Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Preferred Stock, Capital Shares Reserved for Future Issuance				10,350
Preferred Stock, Dividend Rate, Percentage				6.875%
Preferred Stock Dividend Payment Rate Variable Rate Spread				4.332%
Preferred Stock, Shares Issued				9,400
Series E Preferred Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Preferred Stock, Capital Shares Reserved for Future Issuance				16,100
Preferred Stock, Dividend Rate, Percentage		6.50%
Preferred Stock, Shares Issued				16,100
Series F Preferred Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Preferred Stock, Capital Shares Reserved for Future Issuance				23,000
Preferred Stock, Dividend Rate, Percentage	6.125%
Preferred Stock, Shares Issued				23,000
Preferred Stock, Liquidation Preference, Value	$ 575,000
Depositary Share [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Preferred Stock, Shares Issued				61,500,000
Depositary Share [Member] \| Series C Preferred Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Preferred Stock, Shares Issued				13,000,000.0
Depositary Share [Member] \| Series D Preferred Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Preferred Stock, Shares Issued				9,400,000
Depositary Share [Member] \| Series E Preferred Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Preferred Stock, Shares Issued		16,100,000
Depositary Share [Member] \| Series F Preferred Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Preferred Stock, Shares Issued	23,000,000.0

Stockholders' Equity (Common Stock Repurchase Program) (Details) - USD ($) shares in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2020	Sep. 30, 2019	Oct. 22, 2020	Jul. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock Repurchase Program, Authorized Amount					$ 1,000,000,000
Repurchase of common stock shares	(10,300)	(22,500)
Repurchase of common stock, value	$ 144,000,000	$ 291,000,000
Payments for Repurchase of Common Stock		291,000,000	$ 103,000,000
Stock Repurchased During Period, Average Repurchase Price (in dollars per share)	13.95	12.92
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 597,000,000	$ 597,000,000
Stock Repurchased During Period Purchase Date, Shares	11,000	23,300
Stock Repurchased During Period Trade Date, Value	$ 154,000,000	$ 301,000,000
Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Repurchase of common stock shares			(6,900)
Repurchase of common stock, value	$ 1,000,000	$ 1,000,000
Subsequent Event [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock Repurchase Program, Authorized Amount				$ 1,000,000,000

Pledged Assets (Narrative) (Details)	Sep. 30, 2020
Pledged Assets [Abstract]
Risk Of Repurchase Agreement To Stockholders Equity	2.00%

Summary of Significant Accounting Policies (Policy)	9 Months Ended
Summary of Significant Accounting Policies (Policy)	Sep. 30, 2020
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reverse Repurchase Agreements Policy [Policy Text Block]	Reverse Repurchase Agreements and Obligation to Return Securities Borrowed under Reverse Repurchase Agreements We borrow securities to cover short sales of U.S. Treasury securities through reverse repurchase transactions under our master repurchase agreements (see Derivative Instruments below). We account for these as securities borrowing transactions and recognize an obligation to return the borrowed securities at fair value on the balance sheet based on the value of the underlying borrowed securities as of the reporting date. We may also enter into reverse repurchase agreements to earn a yield on excess cash balances. The securities received as collateral in connection with our reverse repurchase agreements mitigate our credit risk exposure to counterparties. Our reverse repurchase agreements typically have maturities of 30 days or less.
New Accounting Pronouncements, Policy [Policy Text Block]	Recent Accounting Pronouncements In June 2016 the Financial Account Standards Board ("FASB") issued Accounting Standards Update 2016-13, Financial Instruments - Credit Losses (Topic 326), which replaces the incurred loss impairment methodology in prior GAAP with a methodology that better reflects expected credit losses. For financial instruments carried at amortized cost, impairment will be measured as a current estimate of expected lifetime credit losses. For available-for-sale investment securities with changes in fair value recorded in accumulated other comprehensive income, the FASB made targeted improvements eliminating the write-down of available-for-sale securities under the "other-than-temporary" impairment model replacing it with an allowance for credit loss model. We adopted ASU 2016-13 effective January 1, 2020, which had no material effect on our financial results. We consider the applicability and impact of all ASUs issued by the FASB. There are no unadopted ASUs that are expected to have a significant impact on our consolidated financial statements when adopted or other recently adopted ASUs that had a significant impact on our consolidated financial statements upon adoption.
Investment Securities	Investment Securities Agency RMBS consist of residential mortgage pass-through securities and collateralized mortgage obligations ("CMOs") guaranteed by the Federal National Mortgage Association ("Fannie Mae"), Federal Home Loan Mortgage Corporation ("Freddie Mac," and together with Fannie Mae, the "GSEs") or the Government National Mortgage Association ("Ginnie Mae"). CRT securities are risk sharing instruments issued by the GSEs, and similarly structured transactions issued by third-party market participants, that synthetically transfer a portion of the risk associated with credit losses within pools of conventional residential mortgage loans from the GSEs and/or third parties to private investors. Unlike Agency RMBS, full repayment of the original principal balance of CRT securities is not guaranteed by a GSE or U.S. Government agency; rather, "credit risk transfer" is achieved by writing down the outstanding principal balance of the CRT securities if credit losses on a related pool of loans exceed certain thresholds. By reducing the amount that they are obligated to repay to holders of CRT securities, the GSEs and/or other third parties offset credit losses on the related loans. Non-Agency RMBS and CMBS (together, "Non-Agency MBS") are backed by residential and commercial mortgage loans, respectively, packaged and securitized by a private institution, such as a commercial bank. Non-Agency MBS typically benefit from credit enhancements derived from structural elements, such as subordination, overcollateralization or insurance, but nonetheless carry a higher level of credit exposure than Agency RMBS. All of our securities are reported at fair value on our consolidated balance sheet. Accounting Standards Codification ("ASC") Topic 320, Investments—Debt and Equity Securities, requires that at the time of purchase, we designate a security as held-to-maturity, available-for-sale or trading, depending on our ability and intent to hold such security to maturity. Alternatively, we may elect the fair value option of accounting for securities pursuant to ASC Topic 825, Financial Instruments. Prior to fiscal year 2017, we primarily designated our investment securities as available-for-sale. On January 1, 2017, we began electing the fair value option of accounting for all investment securities newly acquired after such date. Unrealized gains and losses on securities classified as available-for-sale are reported in accumulated other comprehensive income ("OCI"), whereas unrealized gains and losses on securities for which we elected the fair value option, or are classified as trading, are reported in net income through other gain (loss). Upon the sale of a security designated as available-for-sale, we determine the cost of the security and the amount of unrealized gain or loss to reclassify out of accumulated OCI into earnings based on the specific identification method. In our view, the election of the fair value option simplifies the accounting for investment securities and more appropriately reflects the results of our operations for a reporting period by presenting the fair value changes for these assets in a manner consistent with the presentation and timing of the fair value changes for our derivative instruments. We generally recognize gains or losses through net income on available-for-sale securities only if the security is sold; however, if the fair value of a security declines below its amortized cost and we determine that it is more likely than not that we will incur a realized loss on the security when we sell the asset, we will recognize the difference between the amortized cost and the fair in net income as a component of other gain (loss). Since all of our available-for-sale designated securities consist of Agency RMBS, we do not have an allowance for credit losses. We have not recognized impairment losses on our available-for-sale securities through net income for the periods presented in our consolidated financial statements.
Interest Income	Interest Income Interest income is accrued based on the outstanding principal amount of the investment securities and their contractual terms. Premiums or discounts associated with the purchase of Agency RMBS and non-Agency MBS of high credit quality are amortized or accreted into interest income, respectively, over the projected lives of the securities, including contractual payments and estimated prepayments, using the effective interest method in accordance with ASC Subtopic 310-20, Receivables—Nonrefundable Fees and Other Costs. We estimate long-term prepayment speeds of our mortgage securities using a third-party service and market data. The third-party service provider estimates prepayment speeds using models that incorporate the forward yield curve, primary to secondary mortgage rate spreads, current mortgage rates, mortgage rates of the outstanding loans, age and size of the outstanding loans, loan-to-value ratios, interest rate volatility and other factors. We review the prepayment speeds estimated by the third-party service for reasonableness with consideration given to both historical prepayment speeds and current market conditions. If based on our assessment, we believe that the third-party model does not fully reflect our expectations of the current prepayment landscape, such as during periods of elevated market uncertainty or unique market conditions, we may make adjustments to the models. We review our actual and anticipated prepayment experience on at least a quarterly basis and effective yields are recalculated when differences arise between (i) our previous estimate of future prepayments and (ii) actual prepayments to date and our current estimate of future prepayments. We are required to record an adjustment in the current period to premium amortization / discount accretion for the cumulative effect of the difference in the effective yields as if the recalculated yield had been in place as of the security's acquisition date through the reporting date. At the time we purchase CRT securities and non-Agency MBS that are not of high credit quality, we determine an effective yield based on our estimate of the timing and amount of future cash flows and our cost basis. Our initial cash flow estimates for these investments are based on our observations of current information and events and include assumptions related to interest rates, prepayment rates and the impact of default and severity rates on the timing and amount of credit losses. On at least a quarterly basis, we review the estimated cash flows and make appropriate adjustments based on inputs and analysis received from external sources, internal models, and our judgment regarding such inputs and other factors. Any resulting changes in effective yield are recognized prospectively based on the current amortized cost of the investment adjusted for credit impairments, if any.
Repurchase and Resale Agreements Policy [Policy Text Block]	Repurchase Agreements We finance the acquisition of securities for our investment portfolio primarily through repurchase transactions under master repurchase agreements. Pursuant to ASC Topic 860, Transfers and Servicing, we account for repurchase transactions as collateralized financing transactions, which are carried at their contractual amounts (cost), plus accrued interest. Our repurchase agreements typically have maturities of less than one year but may extend up to five years or more.
Derivative Instruments	Derivative Instruments We use a variety of derivative instruments to hedge a portion of our exposure to market risks, including interest rate, prepayment, extension and liquidity risks. The objective of our risk management strategy is to reduce fluctuations in net book value over a range of interest rate scenarios. In particular, we attempt to mitigate the risk of the cost of our variable rate liabilities increasing during a period of rising interest rates. The primary instruments that we use are interest rate swaps, options to enter into interest rate swaps ("swaptions"), U.S. Treasury securities and U.S. Treasury futures contracts. We also use forward contracts in the Agency RMBS "to-be-announced" market, or TBA securities, to invest in and finance Agency securities and to periodically reduce our exposure to Agency RMBS. We account for derivative instruments in accordance with ASC Topic 815, Derivatives and Hedging ("ASC 815"). ASC 815 requires an entity to recognize all derivatives as either assets or liabilities in our accompanying consolidated balance sheets and to measure those instruments at fair value. None of our derivative instruments have been designated as hedging instruments for accounting purposes under the provisions of ASC 815, consequently changes in the fair value of our derivative instruments are reported in gain (loss) on derivative instruments and other securities, net in our consolidated statements of comprehensive income. Our derivative agreements generally contain provisions that allow for netting or setting off derivative assets and liabilities with the counterparty; however, we report related assets and liabilities on a gross basis in our consolidated balance sheets. Derivative instruments in a gain position are reported as derivative assets at fair value and derivative instruments in a loss position are reported as derivative liabilities at fair value in our consolidated balance sheets. Changes in fair value of derivative instruments and periodic settlements related to our derivative instruments are recorded in gain (loss) on derivative instruments and other securities, net in our consolidated statements of comprehensive income. Cash receipts and payments related to derivative instruments are classified in our consolidated statements of cash flows according to the underlying nature or purpose of the derivative transaction, generally in the investing section. Interest rate swap agreements We use interest rate swaps to economically hedge the variable cash flows associated with our borrowings made under repurchase agreements. Under our interest rate swap agreements, we typically pay a fixed rate and receive a floating rate ("payer swaps") based on a short-term benchmark rate, such as the Secured Overnight Financing Rate ("SOFR"), Overnight Index Swap Rate ("OIS") or three-month London Interbank Offered Rate ("LIBOR"). Our interest rate swaps typically have terms from one to 10 years but may extend up to 20 years or more. Our interest rate swaps are centrally cleared through a registered commodities exchange. The clearing exchange requires that we post an "initial margin" amount determined by the exchange, which is generally intended to be set at a level sufficient to protect the exchange from the interest rate swap's maximum estimated single-day price movement. We also exchange daily settlements of "variation margin" based upon changes in fair value, as measured by the exchange. Pursuant to rules governing central clearing activities, we recognize variation margin settlements as a direct reduction of the carrying value of the interest rate swap asset or liability. Interest rate swaptions We purchase interest rate swaptions to help mitigate the potential impact of larger, more rapid changes in interest rates on the performance of our investment portfolio. Interest rate swaptions provide us the option to enter into an interest rate swap agreement for a predetermined notional amount, stated term and pay and receive interest rates in the future. Our interest rate swaption agreements are not subject to central clearing. The premium paid for interest rate swaptions is reported as an asset in our consolidated balance sheets. The difference between the premium paid and the fair value of the swaption is reported in gain (loss) on derivative instruments and other securities, net in our consolidated statements of comprehensive income. If a swaption expires unexercised, the realized loss on the swaption would be equal to the premium paid. If we sell or exercise a swaption, the realized gain or loss on the swaption would be equal to the difference between the cash or the fair value of the underlying interest rate swap and the premium paid. TBA securities A TBA security is a forward contract for the purchase or sale of Agency RMBS at a predetermined price, face amount, issuer, coupon and stated maturity on an agreed-upon future date. The specific Agency RMBS to be delivered into the contract are not known until shortly before the settlement date. We may choose, prior to settlement, to move the settlement of these securities out to a later date by entering into an offsetting TBA position, net settling the offsetting positions for cash, and simultaneously purchasing or selling a similar TBA contract for a later settlement date (together referred to as a "dollar roll transaction"). The Agency securities purchased or sold for a forward settlement date are typically priced at a discount to equivalent securities settling in the current month. This difference, or "price drop," is the economic equivalent of interest income on the underlying Agency securities, less an implied funding cost, over the forward settlement period (referred to as "dollar roll income"). Consequently, forward purchases of Agency securities and dollar roll transactions represent a form of off-balance sheet financing. We account for TBA contracts as derivative instruments since either the TBA contracts do not settle in the shortest period of time possible or we cannot assert that it is probable at inception and throughout the term of the TBA contract that we will physically settle the contract on the settlement date. We account for TBA dollar roll transactions as a series of derivative transactions. U.S. Treasury securities We use U.S. Treasury securities and U.S. Treasury futures contracts to mitigate the potential impact of changes in interest rates on the performance of our portfolio. We borrow U.S. Treasury securities under reverse repurchase agreements to cover short sales of U.S. Treasury securities. We account for these as securities borrowing transactions and recognize an obligation to return the borrowed securities at fair value on our accompanying consolidated balance sheets based on the value of the underlying U.S. Treasury security as of the reporting date. Gains and losses associated with U.S. Treasury securities and U.S. Treasury futures contracts are recognized in gain (loss) on derivative instruments and other securities, net in our consolidated statements of comprehensive income.

Label	Element	Value
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	$ 1,282,000,000
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	$ 1,520,000,000

Pledged Assets Repurchase Agreements with Counterparties Greater than or Equal to 5% of Equity at Risk (Details) $ in Millions	Sep. 30, 2020 USD ($) days	Dec. 31, 2019 USD ($) days
Repurchase Agreements with Counterparties Greater than or equal to 5% of Equity at Risk [Line Items]
Securities Sold under Agreements to Repurchase \| $	$ 54,566	$ 89,182
Risk Of Repurchase Agreement To Stockholders Equity	2.00%
Weighted Average Days to Maturity \| days	55	55
FICC [Member]
Repurchase Agreements with Counterparties Greater than or equal to 5% of Equity at Risk [Line Items]
Risk Of Repurchase Agreement To Stockholders Equity	10.00%

Pledged Assets

9 Months Ended

Sep. 30, 2020

Pledged Assets [Abstract]

Pledged Assets

Our funding agreements require us to fully collateralize our obligations under the agreements based upon our counterparties' collateral requirements and their determination of the fair value of the securities pledged as collateral, which fluctuates with changes in interest rates, credit quality and liquidity conditions within the investment banking, mortgage finance and real estate industries. Our derivative contracts similarly require us to fully collateralize our obligations under such agreements, which will vary over time based on similar factors as well as our counterparties' determination of the value of the derivative contract. We are typically required to post initial margin upon execution of derivative transactions, such as under our interest rate swap agreements and TBA contracts, and subsequently post or receive variation margin based on daily fluctuations in fair value. Our brokerage and custody agreements and the clearing organizations utilized by our wholly-owned captive broker-dealer subsidiary, Bethesda Securities, LLC, also require that we post minimum daily clearing deposits. If we breach our collateral requirements, we will be required to fully settle our obligations under the agreements, which could include a forced liquidation of our pledged collateral.

Our counterparties also apply a "haircut" to our pledged collateral, which means our collateral is valued at slightly less than market value and limits the amount we can borrow against our securities. This haircut reflects the underlying risk of the specific collateral and protects our counterparty against a change in its value. Our agreements do not specify the haircut; rather haircuts are determined on an individual transaction basis. Consequently, our funding agreements and derivative contracts expose us to credit risk relating to potential losses that could be recognized if our counterparties fail to perform their obligations under such agreements. We minimize this risk by limiting our counterparties to major financial institutions with acceptable credit ratings or to registered clearinghouses and U.S. government agencies, and we monitor our positions with individual counterparties. In the event of a default by a counterparty, we may have difficulty obtaining our assets pledged as collateral to such counterparty and may not receive payments as and when due to us under the terms of our derivative agreements. In the case of centrally cleared instruments, we could be exposed to credit risk if the central clearing agency or a clearing member defaults on its respective obligation to perform under the contract. However, we believe that the risk is minimal due to the clearing exchanges' initial and daily mark-to-market margin requirements, clearinghouse guarantee funds and other resources that are available in the event of a clearing member default.

As of September 30, 2020, our maximum amount at risk with any counterparty related to our repurchase agreements, excluding the Fixed Income Clearing Corporation, was less than 2% of our tangible stockholders' equity (measured as the excess of the value of collateral pledged over the amount of our repurchase liabilities). As of September 30, 2020, approximately 10% of our tangible stockholder's equity was at risk with the Fixed Income Clearing Corporation.

Assets Pledged to Counterparties


	September 30, 2020
Assets Pledged to Counterparties 1	Repurchase Agreements 2		Debt of Consolidated VIEs		Derivative Agreements		Brokerage and Clearing Agreements 3		Total
Agency RMBS - fair value	$	55,136	$	323	$	405	$	301	$	56,165
CRT - fair value	423		—		—		—		423
Non-Agency - fair value	455		—		—		—		455
U.S. Treasury securities - fair value	200		—		—		—		200
Accrued interest on pledged securities	158		1		1		1		161
Restricted cash	648		—		909		—		1,557
Total	$	57,020	$	324	$	1,315	$	302	$	58,961


	December 31, 2019
Assets Pledged to Counterparties 1	Repurchase Agreements 2		Debt of Consolidated VIEs		Derivative Agreements		Brokerage and Clearing Agreements 3		Total
Agency RMBS - fair value	$	92,142	$	371	$	404	$	206	$	93,123
CRT - fair value	309		—		—		—		309
U.S. Treasury securities - fair value	453		—		—		28		481
Accrued interest on pledged securities	267		1		1		1		270
Restricted cash	111		—		340		—		451
Total	$	93,282	$	372	$	745	$	235	$	94,634

________________________________

1.Includes repledged assets received as collateral from counterparties and securities sold but not yet settled.

2.Includes $131 million and $144 million of retained interests in our consolidated VIEs pledged as collateral under repurchase agreements as of September 30, 2020 and December 31, 2019, respectively.

3.Includes margin for TBAs cleared through prime brokers and other clearing deposits.


	September 30, 2020						December 31, 2019
Securities Pledged by Remaining Maturity of Repurchase Agreements 1,2	Fair Value of Pledged Securities		Amortized Cost of Pledged Securities		Accrued Interest on Pledged Securities		Fair Value of Pledged Securities		Amortized Cost of Pledged Securities		Accrued Interest on Pledged Securities
≤ 30 days	$	28,729	$	27,243	$	82	$	56,990	$	55,951	$	167
> 30 and ≤ 60 days	8,666		8,214		24		14,410		14,114		42
> 60 and ≤ 90 days	4,568		4,378		12		7,637		7,536		20
> 90 days	14,051		13,380		40		13,510		13,286		38
Total	$	56,014	$	53,215	$	158	$	92,547	$	90,887	$	267

________________________________

1.Includes $131 million and $144 million of retained interests in our consolidated VIEs pledged as collateral under repurchase agreements as of September 30, 2020 and December 31, 2019, respectively.

2.Excludes $200 million and $357 million of repledged U.S. Treasury securities received as collateral from counterparties as of September 30, 2020 and December 31, 2019, respectively.

Assets Pledged from Counterparties


	September 30, 2020								December 31, 2019
Assets Pledged to AGNC	Reverse Repurchase Agreements		Derivative Agreements		Repurchase Agreements		Total		Reverse Repurchase Agreements		Derivative Agreements		Repurchase Agreements		Total
U.S. Treasury securities - fair value 1	$	8,579	$	—	$	211	$	8,790	$	10,099	$	—	$	1	$	10,100
Cash	—		5		4		9		—		116		—		116
Total	$	8,579	$	5	$	215	$	8,799	$	10,099	$	116	$	1	$	10,216

________________________________

Offsetting Assets and Liabilities

Certain of our repurchase agreements and derivative transactions are governed by underlying agreements that generally provide for a right of setoff under master netting arrangements (or similar agreements), including in the event of default or in the event of bankruptcy of either party to the transactions. We present our assets and liabilities subject to such arrangements on a gross basis in our consolidated balance sheets. The following tables present information about our assets and liabilities that are subject to master netting arrangements and can potentially be offset on our consolidated balance sheets as of September 30, 2020 and December 31, 2019 (in millions):


	Offsetting of Financial and Derivative Assets
	Gross Amounts of Recognized Assets		Gross Amounts Offset in the Consolidated Balance Sheets		Net Amounts of Assets Presented in the Consolidated Balance Sheets		Gross Amounts Not Offset in the Consolidated Balance Sheets				Net Amount
							Financial Instruments		Collateral Received 2
September 30, 2020
Interest rate swap and swaption agreements, at fair value 1	$	46	$	—	$	46	$	—	$	(3)	$	43
TBA securities, at fair value	84		—		84		(8)		—		76
Receivable under reverse repurchase agreements	8,625		—		8,625		(5,463)		(3,147)		15
Total	$	8,755	$	—	$	8,755	$	(5,471)	$	(3,150)	$	134

December 31, 2019
Interest rate swap and swaption agreements, at fair value 1	$	147	$	—	$	147	$	(2)	$	(116)	$	29
TBA securities, at fair value	29		—		29		(4)		—		25
Receivable under reverse repurchase agreements	10,181		—		10,181		(9,852)		(329)		—
Total	$	10,357	$	—	$	10,357	$	(9,858)	$	(445)	$	54


	Offsetting of Financial and Derivative Liabilities
	Gross Amounts of Recognized Liabilities		Gross Amounts Offset in the Consolidated Balance Sheets		Net Amounts of Liabilities Presented in the Consolidated Balance Sheets		Gross Amounts Not Offset in the Consolidated Balance Sheets				Net Amount
							Financial Instruments		Collateral Pledged 2
September 30, 2020
Interest rate swap agreements, at fair value 1	$	—	$	—	$	—	$	—	$	—	$	—
TBA securities, at fair value	8		—		8		(8)		—		—
Repurchase agreements	54,566		—		54,566		(5,463)		(49,103)		—
Total	$	54,574	$	—	$	54,574	$	(5,471)	$	(49,103)	$	—

December 31, 2019
Interest rate swap agreements, at fair value 1	$	2	$	—	$	2	$	(2)	$	—	$	—
TBA securities, at fair value	4		—		4		(4)		—		—
Repurchase agreements	89,182		—		89,182		(9,852)		(79,330)		—
Total	$	89,188	$	—	$	89,188	$	(9,858)	$	(79,330)	$	—

________________________________

Repurchase Agreements and Reverse Repurchase Agreements (Tables)

9 Months Ended

Sep. 30, 2020

Disclosure of Repurchase Agreements [Abstract]

Schedule of Borrowings under Repurchase Agreements and Weighted Average Interest Rates

The following table summarizes our borrowings under repurchase agreements by their remaining maturities as of September 30, 2020 and December 31, 2019 (dollars in millions):


	September 30, 2020					December 31, 2019
Remaining Maturity	Repurchase Agreements		Weighted Average Interest Rate		Weighted Average Days to Maturity	Repurchase Agreements		Weighted Average Interest Rate		Weighted Average Days to Maturity
Agency repo:
≤ 1 month	$	28,119	0.21	%	10	$	56,664	2.19	%	10
> 1 to ≤ 3 months	12,906		0.21	%	50	20,761		2.01	%	53
> 3 to ≤ 6 months	7,642		1.27	%	104	5,683		2.19	%	100
> 6 to ≤ 9 months	5,041		0.32	%	216	1,500		2.66	%	182
> 9 to ≤ 12 months	658		0.62	%	282	2,152		2.41	%	351
> 12 to ≤ 24 months	—		—	%	—	625		2.38	%	411
> 24 to ≤ 36 months	—		—	%	—	1,700		2.45	%	833
Total Agency repo	54,366		0.37	%	55	89,085		2.17	%	55
U.S. Treasury repo:
> 1 day to ≤ 1 month	200		0.10	%	1	97		1.63	%	2
Total	$	54,566	0.37	%	55	$	89,182	2.17	%	55

Fair Value Measurements

9 Months Ended

Sep. 30, 2020

Fair Value Disclosures [Abstract]

Fair Value Measurements

We determine the fair value of financial instruments based on our estimate of the price that would be received to sell the asset or paid to transfer the liability in an orderly transaction between market participants at the measurement date. We utilize a three-level valuation hierarchy for disclosure of fair value measurements based upon the transparency of inputs to the valuation of the instrument as of the measurement date. We categorize a financial instrument within the hierarchy based upon the lowest level of input that is significant to the fair value measurement.

The three levels of valuation hierarchy are defined as follows:

•Level 1 Inputs —Quoted prices (unadjusted) for identical unrestricted assets and liabilities in active markets that are accessible at the measurement date.

•Level 2 Inputs —Quoted prices for similar assets and liabilities in active markets; quoted prices for identical or similar instruments in markets that are not active; and model-derived valuations whose inputs are observable or whose significant value drivers are observable.

•Level 3 Inputs —Instruments with primarily unobservable market data that cannot be corroborated.

We typically obtain price estimates from multiple third-party pricing services and dealers or, if applicable, the registered clearing exchange. The following is a description of the valuation methodologies used for instruments carried at fair value on a recurring basis.

U.S. Treasury securities and futures prices - are valued based on quoted prices for identical instruments in active markets and are classified as Level 1 assets.

TBA securities - are valued using prices obtained from third-party pricing sources based on pricing models that reference recent trading activity.

Interest rate swaps - are valued using the daily settlement price, or fair value, determined by the clearing exchange based on a pricing model that references observable market inputs, including current benchmark rates and the forward yield curve.

Interest rate swaptions - are valued using prices obtained from the counterparty and other third-party pricing models. The pricing models are based on the value of the future interest rate swap that we have the option to enter into as well as the remaining length of time that we have to exercise the option based on observable market inputs, adjusted for non-performance risk, if any.

Investment securities - are valued based on prices obtained from multiple third-party pricing sources. The pricing sources utilize various valuation approaches, including market and income approaches. For Agency RMBS, the pricing sources primarily utilize a matrix pricing technique that interpolates the estimated fair value based on observed quoted prices for forward contracts in the Agency RMBS "to-be-announced" market ("TBA securities") of the same coupon, maturity and issuer, adjusted to reflect the specific characteristics of the pool of mortgages underlying the Agency security, which may include maximum loan balance, loan vintage, loan-to-value ratio, geography and other characteristics as may be appropriate. For other investment securities, the pricing sources primarily utilize discounted cash flow model-derived pricing techniques to estimate the fair value. Such models incorporate market-based discount rate assumptions based on observable inputs such as recent trading activity, credit data, volatility statistics, benchmark interest rate curves, spread measurements to benchmark curves and other market data that are current as of the measurement date and may include certain unobservable inputs, such as assumptions of future levels of prepayment, defaults and loss severities.

The availability of observable inputs can be affected by a wide variety of factors, including the type of instrument, whether the instrument is new and not yet established in the marketplace and other characteristics particular to the instrument. We make inquiries of third-party pricing sources to understand the significant inputs and assumptions they used to determine their prices and that they are derived from orderly transactions, particularly during periods of elevated market turbulence and reduced market liquidity. We also review third-party price estimates and perform procedures to validate their reasonableness, including an analysis of the range of estimates for each position, comparison to recent trade activity for similar securities and for consistency with market conditions observed as of the measurement date. While we do not adjust prices we obtain from pricing sources, we will exclude prices for securities from our estimation of fair value if we determine based on our validation

procedures and our market knowledge and expertise that the price is significantly different from what observable market data would indicate and we cannot obtain an understanding from the third-party source as to the significant inputs used to determine the price.

The markets for interest rate swap, swaption and TBA derivatives and for the investment securities that we invest in are considered to be active markets such that participants transact with sufficient frequency and volume to provide transparent pricing information on an ongoing basis. The liquidity of these markets and the similarity of our securities and derivative instruments to those actively traded enable our pricing sources and us to observe quoted prices in the market and utilize those prices as a basis for formulating fair value measurements. Consequently, we classify these instruments as Level 2 inputs in the fair value hierarchy.


	September 30, 2020						December 31, 2019
	Level 1		Level 2		Level 3		Level 1		Level 2		Level 3
Assets:
Agency securities	$	—	$	66,556	$	—	$	—	$	98,516	$	—
Agency securities transferred to consolidated VIEs	—		323		—		—		371		—
Credit risk transfer securities	—		653		—		—		976		—
Non-Agency securities	—		512		—		—		579		—
U.S. Treasury securities	—		—		—		97		—		—
Interest rate swaps	—		41		—		—		21		—
Swaptions	—		5		—		—		126		—
TBA securities	—		84		—		—		29		—
U.S. Treasury futures	—		—		—		14		—		—
Total	$	—	$	68,174	$	—	$	111	$	100,618	$	—
Liabilities:
Debt of consolidated VIEs	$	—	$	192	$	—	$	—	$	228	$	—
Obligation to return U.S. Treasury securities borrowed under reverse repurchase agreements	8,372		—		—		9,543		—		—
Interest rate swaps	—		—		—		—		2		—
TBA securities	—		8		—		—		4		—
U.S. Treasury futures	5		—		—		—		—		—
Total	$	8,377	$	200	$	—	$	9,543	$	234	$	—

Excluded from the table above are financial instruments presented in our consolidated financial statements at cost. The fair value of our repurchase agreements approximated cost as of September 30, 2020 and December 31, 2019, as the rates on our outstanding repurchase agreements largely corresponded to prevailing rates observed in the repo market. The fair value of cash and cash equivalents, restricted cash, receivables and other payables were determined to approximate cost as of September 30, 2020 and December 31, 2019 due to their short duration. We estimate the fair value of these instruments carried at cost using "Level 1" or "Level 2" inputs.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Net Income (Loss) Per Common Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Weighted Average Number of Shares Outstanding	552.1	546.0	552.9	539.9
Weighted Average Number of Fully Vested Restricted Stock Units and Performance Share Units Outstanding	1.1	0.4	0.9	0.4
Weighted Average Number of Shares Outstanding, Basic	553.2	546.4	553.8	540.3
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements	1.1	0.0	0.0	0.0
Weighted Average Number of Shares Outstanding, Diluted	554.3	546.4	553.8	540.3
Net Income (Loss) Available to Common Stockholders, Basic	$ 637	$ (17)	$ (1,112)	$ (219)
Earnings Per Share, Basic	$ 1.15	$ (0.03)	$ (2.01)	$ (0.41)
Earnings Per Share, Diluted	$ 1.15	$ (0.03)	$ (2.01)	$ (0.41)

- Definition

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=109234566&loc=d3e22583-107794

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 11
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109234566&loc=d3e22694-107794

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 45
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=121326447&loc=d3e1448-109256

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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- Definition

The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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Amount, after deduction of tax, noncontrolling interests, dividends on preferred stock and participating securities; of income (loss) available to common shareholders.

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Derivative and Other Hedging Instruments (Narrative) (Details) $ in Millions	3 Months Ended		6 Months Ended	9 Months Ended
	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2020 USD ($) month	Sep. 30, 2020 USD ($) month	Sep. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)	Jun. 30, 2019 USD ($)	Dec. 31, 2018 USD ($)
Interest Rate Swaption [Member]
Average Maturity (Years)			9 years 6 months	9 years 3 months 18 days
Cash Flow Hedges Derivative Instruments Not Designated As Hedging Instruments Average Months To Expiration \| month			11	7
Notional Amount	$ 6,900			$ 6,900		$ 8,850
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	(1)	$ (19)		(149)	$ (71)
Notional Amount Of Derivatives Not Designated As Hedging Instruments Additions During The Period	0	4,500		2,000	7,150
Notional Amount Of Derivatives Not Designated As Hedging Instruments Settlement Expiration During The Period	$ (2,450)	(250)		$ (3,950)	(2,000)
Derivative, Average Fixed Interest Rate	2.32%			2.32%		2.34%
Interest Rate Derivatives, at Fair Value, Net	$ 5			$ 5		$ 126
Options At Cost			$ 176	141
TBA and Forward Settling Agency Securities [Member]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	283	144		1,196	390
Notional Amount Of Derivatives Not Designated As Hedging Instruments Additions During The Period	80,599	24,305		193,535	70,606
Notional Amount Of Derivatives Not Designated As Hedging Instruments Settlement Expiration During The Period					(75,791)
US Treasury Securities [Member]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	(5)	(40)		(117)	(128)
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	403	(546)		(3,014)	(2,979)
Short [Member] \| US Treasury Securities [Member]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	(15)	(154)		(1,012)	(1,084)
Notional Amount Of Derivatives Not Designated As Hedging Instruments Additions During The Period	2,735	98		12,967	7,404
Notional Amount Of Derivatives Not Designated As Hedging Instruments Settlement Expiration During The Period	2,255	2,710		14,464	(24,116)
Long [Member] \| US Treasury Securities [Member]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	1	5		102	11
Trading Securities Added During the Period	0	353		7,011	1,776
Notional Amount Of Trading Securities Settlement Expiration During The Period	(1,133)	(1,278)		(7,107)	(1,612)
Debt Securities, Trading, and Equity Securities, FV-NI	$ 1	$ 209	$ 1,132	$ 1	$ 209	$ 95	$ 1,134	$ 45

Investment Securities (Summary Of Continuous Unrealized Loss Positions Of Available-For-Sale Security) (Details) - Accumulated Other Comprehensive Income (Loss) [Member] - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Unrealized Loss Position For - Estimated Fair Value - Less than 12 Months	$ 13	$ 1,653
Unrealized Loss Position For - Unrealized Loss - Less than 12 Months	0	(12)
Unrealized Loss Position For - Estimated Fair Value - 12 Months or More	0	6,984
Unrealized Loss Position For - Unrealized Loss - 12 Months or More	0	(63)
Unrealized Loss Position For - Estimated Fair Value - Total	13	8,637
Unrealized Loss Position For - Unrealized Loss - Total	$ 0	$ (75)

Derivative and Other Hedging Instruments (Summary Of Outstanding Interest Rate Swaps) (Details) $ in Millions	3 Months Ended		6 Months Ended	9 Months Ended
	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2020 USD ($) month	Sep. 30, 2020 USD ($) month	Sep. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)
Interest Rate Swaps Linked to Overnight Index Swap Rate	31.00%			31.00%		86.00%
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	$ 403	$ (546)		$ (3,014)	$ (2,979)
Interest Rate Swaps Linked to 3-Month LIBOR	0.00%			0.00%		11.00%
Interest Rate Swaps Linked to Secured Overnight Financing Rate	69.00%			69.00%		3.00%
Interest Rate Swaption [Member]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	$ (1)	(19)		$ (149)	(71)
Notional Amount	$ 6,900			$ 6,900		$ 8,850
Average Fixed Pay Rate	2.32%			2.32%		2.34%
Options At Cost			$ 176	$ 141
Interest Rate Derivatives, at Fair Value, Net	$ 5			$ 5		$ 126
Cash Flow Hedges Derivative Instruments Not Designated As Hedging Instruments Average Months To Expiration \| month			11	7
Average Maturity (Years)			9 years 6 months	9 years 3 months 18 days
Interest Rate Swap [Member]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	140	$ (482)		$ (3,034)	$ (2,097)
Notional Amount	$ 42,975			$ 42,975		$ 79,075
Average Fixed Pay Rate	0.15%			0.15%		1.29%
Average Receive Rate	0.08%			0.08%		1.59%
Average Maturity (Years)			2 years 8 months 12 days	5 years 3 months 18 days
Less Than or Equal to One Year [Member] \| Interest Rate Swaption [Member]
Notional Amount	$ 6,400			$ 6,400		$ 5,650
Average Fixed Pay Rate	2.35%			2.35%		2.26%
Options At Cost			$ 123	$ 133
Interest Rate Derivatives, at Fair Value, Net	$ 3			$ 3		$ 80
Cash Flow Hedges Derivative Instruments Not Designated As Hedging Instruments Average Months To Expiration \| month			8	6
Average Maturity (Years)			9 years 3 months 18 days	9 years 2 months 12 days
Greater Than One Year and Less Than or Equal to Two Years [Member] \| Interest Rate Swaption [Member]
Notional Amount	$ 500			$ 500		$ 3,200
Average Fixed Pay Rate	1.87%			1.87%		2.50%
Options At Cost			$ 53	$ 8
Interest Rate Derivatives, at Fair Value, Net	$ 2			$ 2		$ 46
Cash Flow Hedges Derivative Instruments Not Designated As Hedging Instruments Average Months To Expiration \| month			16	17
Average Maturity (Years)			10 years	10 years
Greater Than One Year and Less Than or Equal to Three Years [Member] \| Interest Rate Swap [Member]
Notional Amount	$ 8,750			$ 8,750		$ 59,700
Average Fixed Pay Rate	0.04%			0.04%		1.30%
Average Receive Rate	0.08%			0.08%		1.58%
Average Maturity (Years)			1 year 7 months 6 days	2 years 7 months 6 days
Greater Than Three Years and Less Than or Equal to Five Years [Member] \| Interest Rate Swap [Member]
Notional Amount	$ 16,750			$ 16,750		$ 9,850
Average Fixed Pay Rate	0.10%			0.10%		1.17%
Average Receive Rate	0.08%			0.08%		1.55%
Average Maturity (Years)			3 years 9 months 18 days	4 years 3 months 18 days
Greater Than Five Years and Less than or Equal to Seven Years [Member] \| Interest Rate Swap [Member]
Notional Amount	$ 9,800			$ 9,800		$ 5,650
Average Fixed Pay Rate	0.21%			0.21%		1.34%
Average Receive Rate	0.08%			0.08%		1.70%
Average Maturity (Years)			6 years 4 months 24 days	6 years
Greater Than Seven Years and Less than or Equal to Ten Years [Member] \| Interest Rate Swap [Member]
Notional Amount	$ 6,200			$ 6,200		$ 2,850
Average Fixed Pay Rate	0.28%			0.28%		1.36%
Average Receive Rate	0.08%			0.08%		1.58%
Average Maturity (Years)			8 years 10 months 24 days	8 years 9 months 18 days
Greater Than Ten Years [Member] \| Interest Rate Swap [Member]
Notional Amount	$ 1,475			$ 1,475		$ 1,025
Average Fixed Pay Rate	0.47%			0.47%		1.64%
Average Receive Rate	0.08%			0.08%		1.78%
Average Maturity (Years)			15 years 4 months 24 days	14 years 4 months 24 days

Document and Entity Information - shares	9 Months Ended
Document and Entity Information - shares	Sep. 30, 2020	Oct. 31, 2020
Entity Information [Line Items]
Entity Incorporation, State or Country Code	DE
Document Transition Report	false
Document Quarterly Report	true
Entity Tax Identification Number	26-1701984
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2020
Entity File Number	001-34057
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Entity Registrant Name	AGNC INVESTMENT CORP.
Entity Address, Address Line One	2 Bethesda Metro Center, 12th Floor
Entity Address, City or Town	Bethesda
Entity Address, State or Province	MD
Entity Address, Postal Zip Code	20814
City Area Code	301
Local Phone Number	968-9315
Entity Central Index Key	0001423689
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Current Fiscal Year End Date	--12-31
Entity Common Stock, Shares Outstanding		545,211,569
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Shell Company	false
Common Stock [Member]
Entity Information [Line Items]
Title of 12(b) Security	Common Stock, par value $0.01 per share
Trading Symbol	AGNC
Security Exchange Name	NASDAQ
Depository shares each representing a 1/1,000th interest in a share of 7.000% Series C Fixed-to-Floating Rate Cumulative Redeemable Preferred Stock [Member]
Entity Information [Line Items]
Title of 12(b) Security	Depositary shares of 7.000% Series C Fixed-to-Floating Rate Cumulative Redeemable Preferred Stock
Trading Symbol	AGNCN
Security Exchange Name	NASDAQ
Depository shares each representing a 1/1,000th interest in a share of 6.875% Series D Fixed-to-Floating Rate Cumulative Redeemable Preferred Stock [Member]
Entity Information [Line Items]
Title of 12(b) Security	Depositary shares of 6.875% Series D Fixed-to-Floating Rate Cumulative Redeemable Preferred Stock
Trading Symbol	AGNCM
Security Exchange Name	NASDAQ
Depository shares each representing a 1/1000th interest in a share of 6.500% Series E Fixed-to-Floating Rate Cumulative Redeemable Preferred Stock [Member]
Entity Information [Line Items]
Title of 12(b) Security	Depositary shares of 6.50% Series E Fixed-to-Floating Rate Cumulative Redeemable Preferred Stock
Trading Symbol	AGNCO
Security Exchange Name	NASDAQ
Depositary shares each representing a 1/1000th interest in a share of 6.125% Series F Fixed-to-Floating Rate Cumulative Redeemable Preferred Stock [Member]
Entity Information [Line Items]
Title of 12(b) Security	Depositary shares of 6.125% Series F Fixed-to-Floating Rate Cumulative Redeemable Preferred Stock
Trading Symbol	AGNCP
Security Exchange Name	NASDAQ

Investment Securities (Components Of Investment Securities) (Details) - USD ($) $ in Millions	6 Months Ended	9 Months Ended
	Jun. 30, 2020	Sep. 30, 2020	Dec. 31, 2019
Schedule of Investments [Line Items]
Debt Securities, Trading		$ 51,771	$ 80,289
Debt Securities, Trading and Available-for-sale		68,044	100,442
Amortized cost		$ 65,024	$ 98,670
Weighted average coupon		3.59%	3.68%
Weighted average yield		2.56%	3.07%
Future Prepayment Rate Assumption Of Investment Portfolio	10.80%	15.90%
Available-for-sale Securities [Member]
Schedule of Investments [Line Items]
Par value		$ 14,763	$ 19,081
Unamortized discount		(7)	(12)
Unamortized premium		683	987
Amortized cost		15,439	20,056
Gross unrealized gains	$ 172	834
Gross unrealized losses	(75)	0
Total available-for-sale securities, at fair value		16,273	20,153
Trading Securities [Member]
Schedule of Investments [Line Items]
Unamortized discount		(48)	(85)
Unamortized premium		1,947	2,219
Debt Securities, Trading, Unrealized Gain	1,729	2,232
Debt Securities, Trading, Unrealized Loss	(54)	(46)
Trading Securities, Cost		49,585	78,614
Trading Securities Par		47,686	76,480
Fannie Mae [Member]
Schedule of Investments [Line Items]
Debt Securities, Trading		34,293	47,215
Debt Securities, Trading and Available-for-sale		$ 46,087	$ 62,309
Weighted average coupon		3.49%	3.62%
Weighted average yield		2.49%	3.03%
Fannie Mae [Member] \| Available-for-sale Securities [Member]
Schedule of Investments [Line Items]
Par value		$ 10,703	$ 14,301
Unamortized discount		(6)	(10)
Unamortized premium		479	711
Amortized cost		11,176	15,002
Gross unrealized gains	142	618
Gross unrealized losses	(50)	0
Total available-for-sale securities, at fair value		11,794	15,094
Fannie Mae [Member] \| Trading Securities [Member]
Schedule of Investments [Line Items]
Unamortized discount		(20)	(68)
Unamortized premium		1,285	1,218
Debt Securities, Trading, Unrealized Gain	991	1,411
Debt Securities, Trading, Unrealized Loss	(32)	(7)
Trading Securities, Cost		32,889	46,256
Trading Securities Par		31,624	45,106
Freddie Mac [Member]
Schedule of Investments [Line Items]
Debt Securities, Trading		16,310	31,519
Debt Securities, Trading and Available-for-sale		$ 20,774	$ 36,559
Weighted average coupon		3.79%	3.75%
Weighted average yield		2.66%	3.09%
Freddie Mac [Member] \| Available-for-sale Securities [Member]
Schedule of Investments [Line Items]
Par value		$ 4,046	$ 4,762
Unamortized discount		(1)	(2)
Unamortized premium		204	276
Amortized cost		4,249	5,036
Gross unrealized gains	29	215
Gross unrealized losses	(25)	0
Total available-for-sale securities, at fair value		4,464	5,040
Freddie Mac [Member] \| Trading Securities [Member]
Schedule of Investments [Line Items]
Unamortized discount		(1)	(2)
Unamortized premium		641	967
Debt Securities, Trading, Unrealized Gain	691	782
Debt Securities, Trading, Unrealized Loss	(18)	(3)
Trading Securities, Cost		15,531	30,846
Trading Securities Par		14,891	29,881
Ginnie Mae [Member]
Schedule of Investments [Line Items]
Debt Securities, Trading		3	0
Debt Securities, Trading and Available-for-sale		$ 18	$ 19
Weighted average coupon		3.58%	3.77%
Weighted average yield		2.22%	2.08%
Ginnie Mae [Member] \| Available-for-sale Securities [Member]
Schedule of Investments [Line Items]
Par value		$ 14	$ 18
Unamortized discount		0	0
Unamortized premium		0	0
Amortized cost		14	18
Gross unrealized gains	1	1
Gross unrealized losses	0	0
Total available-for-sale securities, at fair value		15	19
Ginnie Mae [Member] \| Trading Securities [Member]
Schedule of Investments [Line Items]
Unamortized discount		0	0
Unamortized premium		0	0
Debt Securities, Trading, Unrealized Gain	0	0
Debt Securities, Trading, Unrealized Loss	0	0
Trading Securities, Cost		3	0
Trading Securities Par		3	0
Mortgage-backed Securities, Issued by Private Enterprises [Member]
Schedule of Investments [Line Items]
Debt Securities, Trading		177	209
Debt Securities, Trading and Available-for-sale		$ 177	$ 209
Weighted average coupon		4.20%	4.05%
Weighted average yield		0.53%	4.39%
Mortgage-backed Securities, Issued by Private Enterprises [Member] \| Available-for-sale Securities [Member]
Schedule of Investments [Line Items]
Par value		$ 0	$ 0
Unamortized discount		0	0
Unamortized premium		0	0
Amortized cost		0	0
Gross unrealized gains	0	0
Gross unrealized losses	0	0
Total available-for-sale securities, at fair value		0	0
Mortgage-backed Securities, Issued by Private Enterprises [Member] \| Trading Securities [Member]
Schedule of Investments [Line Items]
Unamortized discount		(11)	(10)
Unamortized premium		3	1
Debt Securities, Trading, Unrealized Gain	10	8
Debt Securities, Trading, Unrealized Loss	0	(4)
Trading Securities, Cost		173	199
Trading Securities Par		181	208
Commercial Mortgage Backed Securities [Member]
Schedule of Investments [Line Items]
Debt Securities, Trading		335	370
Debt Securities, Trading and Available-for-sale		$ 335	$ 370
Weighted average coupon		4.13%	4.49%
Weighted average yield		4.40%	4.38%
Commercial Mortgage Backed Securities [Member] \| Available-for-sale Securities [Member]
Schedule of Investments [Line Items]
Par value		$ 0	$ 0
Unamortized discount		0	0
Unamortized premium		0	0
Amortized cost		0	0
Gross unrealized gains	0	0
Gross unrealized losses	0	0
Total available-for-sale securities, at fair value		0	0
Commercial Mortgage Backed Securities [Member] \| Trading Securities [Member]
Schedule of Investments [Line Items]
Unamortized discount		(4)	(3)
Unamortized premium		6	7
Debt Securities, Trading, Unrealized Gain	19	28
Debt Securities, Trading, Unrealized Loss	(1)	(4)
Trading Securities, Cost		311	352
Trading Securities Par		309	348
Credit Risk Transfer Securities [Member]
Schedule of Investments [Line Items]
Debt Securities, Trading		653	976
Debt Securities, Trading and Available-for-sale		$ 653	$ 976
Weighted average coupon		3.31%	5.07%
Weighted average yield		3.47%	4.05%
Credit Risk Transfer Securities [Member] \| Available-for-sale Securities [Member]
Schedule of Investments [Line Items]
Par value		$ 0	$ 0
Unamortized discount		0	0
Unamortized premium		0	0
Amortized cost		0	0
Gross unrealized gains	0	0
Gross unrealized losses	0	0
Total available-for-sale securities, at fair value		0	0
Credit Risk Transfer Securities [Member] \| Trading Securities [Member]
Schedule of Investments [Line Items]
Unamortized discount		(12)	(2)
Unamortized premium		12	26
Debt Securities, Trading, Unrealized Gain	18	3
Debt Securities, Trading, Unrealized Loss	$ (3)	(28)
Trading Securities, Cost		678	961
Trading Securities Par		678	937
Credit Risk Transfer Securities [Member] \| Securities Remeasured at Fair Value [Member]
Schedule of Investments [Line Items]
Debt Securities, Trading and Available-for-sale		$ 653	$ 976

Investment Securities (Tables)

9 Months Ended

Sep. 30, 2020

Investments, Debt and Equity Securities [Abstract]

Securities by Credit Rating [Table Text Block]

As of September 30, 2020 and December 31, 2019, our investments in CRT and non-Agency securities had the following credit ratings:


	September 30, 2020						December 31, 2019
CRT and Non-Agency Security Credit Ratings 1	CRT		RMBS		CMBS		CRT		RMBS		CMBS
AAA	$	—	$	—	$	39	$	—	$	—	$	43
AA	—		20		181		—		81		214
A	—		33		22		13		25		34
BBB	42		82		55		67		71		69
BB	204		27		34		471		21		10
B	252		5		4		308		4		—
Not Rated	155		10		—		117		7		—
Total	$	653	$	177	$	335	$	976	$	209	$	370

________________________________

1.Represents the lowest of Standard and Poor's ("S&P"), Moody's, Fitch, DBRS, Kroll Bond Rating Agency ("KBRA") and Morningstar credit ratings, stated in terms of the S&P equivalent rating as of each date.

Available-for-sale Securities [Table Text Block]


	September 30, 2020
	Agency RMBS									Non-Agency
Investment Securities	Fannie Mae			Freddie Mac			Ginnie Mae			RMBS			CMBS			CRT			Total
Available-for-sale securities:
Par value	$	10,703		$	4,046		$	14		$	—		$	—		$	—		$	14,763
Unamortized discount	(6)			(1)			—			—			—			—			(7)
Unamortized premium	479			204			—			—			—			—			683
Amortized cost	11,176			4,249			14			—			—			—			15,439
Gross unrealized gains	618			215			1			—			—			—			834
Gross unrealized losses	—			—			—			—			—			—			—
Total available-for-sale securities, at fair value	11,794			4,464			15			—			—			—			16,273
Securities remeasured at fair value through earnings:
Par value	31,624			14,891			3			181			309			678			47,686
Unamortized discount	(20)			(1)			—			(11)			(4)			(12)			(48)
Unamortized premium	1,285			641			—			3			6			12			1,947
Amortized cost	32,889			15,531			3			173			311			678			49,585
Gross unrealized gains	1,411			782			—			8			28			3			2,232
Gross unrealized losses	(7)			(3)			—			(4)			(4)			(28)			(46)
Total securities remeasured at fair value through earnings	34,293			16,310			3			177			335			653			51,771
Total securities, at fair value	$	46,087		$	20,774		$	18		$	177		$	335		$	653		$	68,044
Weighted average coupon as of September 30, 2020	3.49		%	3.79		%	3.58		%	4.20		%	4.13		%	3.31		%	3.59		%
Weighted average yield as of September 30, 2020 1	2.49		%	2.66		%	2.22		%	0.53		%	4.40		%	3.47		%	2.56		%

________________________________

1.Incorporates a weighted average future constant prepayment rate assumption of 15.9% based on forward rates as of September 30, 2020.


	December 31, 2019
	Agency RMBS									Non-Agency
Investment Securities	Fannie Mae			Freddie Mac			Ginnie Mae			RMBS			CMBS			CRT			Total
Available-for-sale securities:
Par value	$	14,301		$	4,762		$	18		$	—		$	—		$	—		$	19,081
Unamortized discount	(10)			(2)			—			—			—			—			(12)
Unamortized premium	711			276			—			—			—			—			987
Amortized cost	15,002			5,036			18			—			—			—			20,056
Gross unrealized gains	142			29			1			—			—			—			172
Gross unrealized losses	(50)			(25)			—			—			—			—			(75)
Total available-for-sale securities, at fair value	15,094			5,040			19			—			—			—			20,153
Securities remeasured at fair value through earnings:
Par value	45,106			29,881			—			208			348			937			76,480
Unamortized discount	(68)			(2)			—			(10)			(3)			(2)			(85)
Unamortized premium	1,218			967			—			1			7			26			2,219
Amortized cost	46,256			30,846			—			199			352			961			78,614
Gross unrealized gains	991			691			—			10			19			18			1,729
Gross unrealized losses	(32)			(18)			—			—			(1)			(3)			(54)
Total securities remeasured at fair value through earnings	47,215			31,519			—			209			370			976			80,289
Total securities, at fair value	$	62,309		$	36,559		$	19		$	209		$	370		$	976		$	100,442
Weighted average coupon as of December 31, 2019	3.62		%	3.75		%	3.77		%	4.05		%	4.49		%	5.07		%	3.68		%
Weighted average yield as of December 31, 2019 1	3.03		%	3.09		%	2.08		%	4.39		%	4.38		%	4.05		%	3.07		%

________________________________

1.Incorporates a weighted average future constant prepayment rate assumption of 10.8% based on forward rates as of December 31, 2019.

Components of Investment Securities

The following tables summarize our investment securities as of September 30, 2020 and December 31, 2019, excluding TBA securities, (dollars in millions). Details of our TBA securities as of each of the respective dates are included in Note 6.


	September 30, 2020				December 31, 2019
Investment Securities	Amortized Cost		Fair Value		Amortized Cost		Fair Value
Agency RMBS:
Fixed rate	$	63,307	$	66,278	$	96,375	$	98,074
Adjustable rate	96		99		160		163
CMO	327		341		441		447
Interest-only and principal-only strips	117		142		146		164
Multifamily	17		19		37		39
Total Agency RMBS	63,864		66,879		97,159		98,887
Non-Agency RMBS	172		177		198		209
CMBS	310		335		352		370
CRT securities	678		653		961		976
Total investment securities	$	65,024	$	68,044	$	98,670	$	100,442

Summary Of Agency Securities Estimated Weighted Average Life Classifications

The following table summarizes our investments as of September 30, 2020 and December 31, 2019 according to their estimated weighted average life classification (dollars in millions):


	September 30, 2020						December 31, 2019
Estimated Weighted Average Life of Investment Securities	Fair Value		Amortized Cost		Weighted Average Coupon	Weighted Average Yield	Fair Value		Amortized Cost		Weighted Average Coupon	Weighted Average Yield
≤ 3 years	$	2,420	$	2,387	3.65%	2.01%	$	2,671	$	2,654	3.54%	2.61%
> 3 years and ≤ 5 years	37,564		35,873		3.76%	2.62%	10,822		10,563		3.85%	3.20%
> 5 years and ≤10 years	27,961		26,665		3.35%	2.51%	86,492		85,002		3.67%	3.07%
> 10 years	99		99		4.08%	3.71%	457		451		3.31%	3.06%
Total	$	68,044	$	65,024	3.59%	2.56%	$	100,442	$	98,670	3.68%	3.07%

Summary of Continuous Unrealized Loss Position of Available for Sale Securities

The following table presents the gross unrealized loss and fair values of securities classified as available-for-sale by length of time that such securities have been in a continuous unrealized loss position as of September 30, 2020 and December 31, 2019 (in millions):


	Unrealized Loss Position For
	Less than 12 Months				12 Months or More				Total
Securities Classified as Available-for-Sale	Fair Value		Unrealized Loss		Fair Value		Unrealized Loss		Fair Value		Unrealized Loss
September 30, 2020	$	13	$	—	$	—	$	—	$	13	$	—
December 31, 2019	$	1,653	$	(12)	$	6,984	$	(63)	$	8,637	$	(75)

Summary of Net Gain from Sale of Agency Securities

The following table is a summary of our net gain (loss) from the sale of investment securities for the three and nine months ended September 30, 2020 and 2019 by investment classification of accounting (in millions):


	Three Months Ended June 30,
	2020						2019
Investment Securities	Available-for-Sale Securities 2		Fair Value Option Securities		Total		Available-for-Sale Securities 2		Fair Value Option Securities		Total
Investment securities sold, at cost	$	—	$	(13,430)	$	(13,430)	$	—	$	(5,048)	$	(5,048)
Proceeds from investment securities sold 1	—		13,776		13,776		—		5,137		5,137
Net gain (loss) on sale of investment securities	$	—	$	346	$	346	$	—	$	89	$	89

Gross gain on sale of investment securities	$	—	$	354	$	354	$	—	$	90	$	90
Gross loss on sale of investment securities	—		(8)		(8)		—		(1)		(1)
Net gain (loss) on sale of investment securities	$	—	$	346	$	346	$	—	$	89	$	89


	Nine Months Ended September 30,
	2020						2019
Investment Securities	Available-for-Sale Securities 2		Fair Value Option Securities		Total		Available-for-Sale Securities 2		Fair Value Option Securities		Total
Investment securities sold, at cost	$	(1,433)	$	(67,342)	$	(68,775)	$	(705)	$	(17,379)	$	(18,084)
Proceeds from investment securities sold 1	1,473		68,295		69,768		696		17,669		18,365
Net gain (loss) on sale of investment securities	$	40	$	953	$	993	$	(9)	$	290	$	281

Gross gain on sale of investment securities	$	40	$	1,050	$	1,090	$	—	$	294	$	294
Gross loss on sale of investment securities	—		(97)		(97)		(9)		(4)		(13)
Net gain (loss) on sale of investment securities	$	40	$	953	$	993	$	(9)	$	290	$	281

________________________________

1.Proceeds include cash received during the period, plus receivable for investment securities sold during the period as of period end.

2.See Note 10 for a summary of changes in accumulated OCI.

Consolidated Balance Sheets (Parentheticals) - USD ($) shares in Thousands, $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Financial Instruments Owned and Pledged as Collateral [Line Items]
Security Owned and Pledged as Collateral, Fair Value	$ 56,014,000	$ 92,547,000
Preferred Stock, Liquidation Preference, Value	1,538,000	$ 963,000
Preferred Stock C, Liquidation Preference, Value	325,000
Preferred Stock D, Liquidation Preference, Value	$ 235,000
Common Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Common Stock, Shares Authorized	1,500,000	900,000
Common Stock, Shares, Issued	545,200	540,900
Common Stock, Shares, Outstanding		540,900
Agency Securities [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Security Owned and Pledged as Collateral, Fair Value	$ 55,711,000	$ 92,608,000
Credit Risk Transfer Securities [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Security Owned and Pledged as Collateral, Fair Value	423,000	309,000
Mortgage-backed Securities, Issued by Private Enterprises [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Security Owned and Pledged as Collateral, Fair Value	455,000	0
US Treasury Securities [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Security Owned and Pledged as Collateral, Fair Value	200,000	481,000
Receivable for securities sold [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Security Owned and Pledged as Collateral, Fair Value	10,000
Asset Pledged as Collateral [Member] \| Credit Risk Transfer Securities [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Security Owned and Pledged as Collateral, Fair Value	413,000	309,000
Asset Pledged as Collateral [Member] \| US Treasury Securities [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Security Owned and Pledged as Collateral, Fair Value	$ 0	$ 97,000

Unaudited Interim Consolidated Financial Statements	9 Months Ended
Unaudited Interim Consolidated Financial Statements	Sep. 30, 2019
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Information [Text Block]	Basis of Presentation The unaudited interim consolidated financial statements of AGNC Investment Corp. (referred throughout this report as the "Company," "we," "us" and "our") are prepared in accordance with U.S. generally accepted accounting principles ("GAAP") for interim financial information and pursuant to the requirements for reporting on Form 10-Q and Article 10 of Regulation S-X. The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of income and expenses during the reporting period. In the opinion of management, all adjustments, consisting solely of normal recurring accruals, necessary for the fair presentation of financial statements for the interim period have been included. The current period’s results of operations are not necessarily indicative of results that ultimately may be achieved for the year. Our unaudited interim consolidated financial statements include the accounts of all our wholly-owned subsidiaries and variable interest entities for which we are the primary beneficiary. Significant intercompany accounts and transactions have been eliminated

Repurchase Agreements And Other Debt (Repurchase Arrangements And Weighted Average Interest Rates Classified By Original Maturities) (Details) $ in Millions	Sep. 30, 2020 USD ($) days	Dec. 31, 2019 USD ($) days
Receivable Under Reverse Repurchase Agreements	$ 8,625	$ 10,181
Repurchase Agreements	$ 54,566	$ 89,182
Weighted Average Interest Rate	0.37%	2.17%
Weighted Average Days to Maturity \| days	55	55
Maturity Overnight [Member]
Repurchase Agreements	$ 8,900	$ 17,000
30 Days or Less [Member]
Repurchase Agreements	$ 28,119	$ 56,664
Weighted Average Interest Rate	0.21%	2.19%
Weighted Average Days to Maturity \| days	10	10
1 to 3 Months
Repurchase Agreements	$ 12,906	$ 20,761
Weighted Average Interest Rate	0.21%	2.01%
Weighted Average Days to Maturity \| days	50	53
3 to 6 Months
Repurchase Agreements	$ 7,642	$ 5,683
Weighted Average Interest Rate	1.27%	2.19%
Weighted Average Days to Maturity \| days	104	100
6 to 9 Months
Repurchase Agreements	$ 5,041	$ 1,500
Weighted Average Interest Rate	0.32%	2.66%
Weighted Average Days to Maturity \| days	216	182
9 to 12 Months
Repurchase Agreements	$ 658	$ 2,152
Weighted Average Interest Rate	0.62%	2.41%
Weighted Average Days to Maturity \| days	282	351
12 to 24 Months
Repurchase Agreements	$ 0	$ 625
Weighted Average Interest Rate	0.00%	2.38%
Weighted Average Days to Maturity \| days	0	411
24 to 36 Months
Repurchase Agreements	$ 0	$ 1,700
Weighted Average Interest Rate	0.00%	2.45%
Weighted Average Days to Maturity \| days	0	833
US Treasury Securities [Member] \| 2 Days to 1 Month [Member]
Repurchase Agreements	$ 200	$ 97
Weighted Average Interest Rate	0.10%	1.63%
Weighted Average Days to Maturity \| days	1	2
FICC [Member]
Obligation to Return Securities Borrowed Under Reverse Repurchase Agreements at Fair Value	$ 3,600	$ 5,400
US Government Agencies Debt Securities [Member]
Repurchase Agreements	$ 54,366	$ 89,085
Weighted Average Interest Rate	0.37%	2.17%
Weighted Average Days to Maturity \| days	55	55

Stockholders' Equity (Tables)

9 Months Ended

Sep. 30, 2020

Equity [Abstract]

Preferred Stock [Table Text Block]


Fixed-to-Floating Rate Cumulative Redeemable Preferred Stock 1	Issuance Date	Depositary Shares Issued and Outstanding	Carrying Value		Aggregate Liquidation Preference		Fixed Rate	Optional Redemption Date 2	Fixed-to-Floating Rate Conversion Date	Floating Annual Rate
Series C	August 22, 2017	13.0	315		325		7.000%	October 15, 2022	October 15, 2022	3M LIBOR + 5.111%
Series D	March 6, 2019	9.4	227		235		6.875%	April 15, 2024	April 15, 2024	3M LIBOR + 4.332%
Series E	October 3, 2019	16.1	390		403		6.500%	October 15, 2024	October 15, 2024	3M LIBOR + 4.993%
Series F	February 11, 2020	23.0	557		575		6.125%	April 15, 2025	April 15, 2025	3M LIBOR + 4.697%
Total		61.5	$	1,489	$	1,538

________________________________

Schedule of Accumulated Other Comprehensive Income (Loss)

The following table summarizes changes to accumulated OCI for the three and nine months ended September 30, 2020 and 2019 (in millions):


	Three Months Ended September 30,				Nine Months Ended September 30,
Accumulated Other Comprehensive Income (Loss)	2020		2019		2020		2019
Beginning Balance	$	764	$	(164)	$	97	$	(943)
OCI before reclassifications	70		246		777		1,016
Net loss amounts for available-for-sale securities reclassified from accumulated OCI to realized gain (loss) on sale of investment securities, net	—		—		(40)		9
Ending Balance	$	834	$	82	$	834	$	82

Investment Securities (Summary Of Changes In Accumulated OCI For Available-For-Sale Security) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Unrealized Gains and (Losses), Net	$ 70	$ 246	$ 737	$ 1,025
Agency Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning OCI Balance	764	(164)	97	(943)
Unrealized Gains and (Losses), Net	70	246	777	1,016
Reversal of Unrealized (Gains) and Losses, Net on Realization	0	0	(40)	9
Ending OCI Balance	$ 834	$ 82	$ 834	$ 82

Subsequent Event	9 Months Ended
Subsequent Event	Sep. 30, 2020
Subsequent Events [Abstract]
Subsequent Event	Subsequent Events Common Stock Dividend Declaration On October 8, 2020, our Board of Directors declared a monthly dividend of $0.12 per common share payable on November 11, 2020 to common stockholders of record as of October 31, 2020. Common Stock Repurchase Program On October 22, 2020 our Board of Directors terminated our existing stock repurchase plan (see Note 10) that was due to expire on December 31, 2020 and replaced it with a new plan authorizing us to repurchase up to $1 billion of common stock through December 31, 2021. Under the new plan, we may repurchase shares in the open market or through privately negotiated transactions or pursuant to a trading plan that may be adopted in accordance with Rule 10b5-1 of the Securities Exchange Act of 1934, as amended. Our stock repurchase program may be limited or terminated at any time without prior notice. We intend to repurchase shares under the stock repurchase program only when the repurchase price is less than our then-current estimate of tangible net book value per common share.

Organization (Details)	9 Months Ended
Organization (Details)	Sep. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Required Annual Distribution of Taxable Net Income	90.00%
Intended annual distribution of taxable net income	100.00%

Stockholders' Equity

3 Months Ended

Sep. 30, 2020

Equity [Abstract]

Stockholders' Equity

Preferred Stock

We are authorized to designate and issue up to 10.0 million shares of preferred stock in one or more classes or series. As of September 30, 2020, 13,800, 10,350, 16,100 and 23,000 shares of preferred stock were designated as 7.00% Series C Fixed-to-Floating Rate Cumulative Redeemable Preferred Stock, 6.875% Series D Fixed-to-Floating Rate Cumulative Redeemable Preferred Stock, 6.50% Series E Fixed-to-Floating Rate Cumulative Redeemable Preferred Stock and 6.125% Series F Fixed-to-Floating Rate Cumulative Redeemable Preferred Stock, respectively, (referred to as "Series C, D, E and F Preferred Stock", respectively). During February 2020, we issued $575 million, or 23,000 shares, of 6.125% Series F Preferred Stock, for net proceeds of $557 million. As of September 30, 2020, 13,000, 9,400, 16,100 and 23,000 shares of Series C, D, E and F Preferred Stock, respectively, were issued and outstanding, with an aggregate carrying value of $1,489 million and aggregate liquidation preference of $1,538 million. Each share of preferred stock is represented by 1,000 depositary shares.

Our preferred stock ranks senior to our common stock with respect to the payment of dividends and the distribution of assets upon a voluntary or involuntary liquidation, dissolution or winding up of the Company. Our preferred stock has no stated maturity, is not subject to any sinking fund or mandatory redemption and each series of preferred stock ranks on parity with one another. Under certain circumstances upon a change of control, our preferred stock is convertible to shares of our common stock. Holders of our preferred stock and depositary shares underlying our preferred stock have no voting rights, except under limited conditions. Beginning on each series' optional redemption date, we may redeem shares at $25.00 per depositary share, plus accumulated and unpaid dividends (whether or not declared), exclusively at our option.

The following table includes a summary of preferred stock depositary shares issued and outstanding as of September 30, 2020 (dollars and shares in millions):


Fixed-to-Floating Rate Cumulative Redeemable Preferred Stock 1	Issuance Date	Depositary Shares Issued and Outstanding	Carrying Value		Aggregate Liquidation Preference		Fixed Rate	Optional Redemption Date 2	Fixed-to-Floating Rate Conversion Date	Floating Annual Rate
Series C	August 22, 2017	13.0	315		325		7.000%	October 15, 2022	October 15, 2022	3M LIBOR + 5.111%
Series D	March 6, 2019	9.4	227		235		6.875%	April 15, 2024	April 15, 2024	3M LIBOR + 4.332%
Series E	October 3, 2019	16.1	390		403		6.500%	October 15, 2024	October 15, 2024	3M LIBOR + 4.993%
Series F	February 11, 2020	23.0	557		575		6.125%	April 15, 2025	April 15, 2025	3M LIBOR + 4.697%
Total		61.5	$	1,489	$	1,538

________________________________

1.Fixed-to-floating rate redeemable preferred stock accrue dividends at an annual fixed rate of the $25.00 liquidation preference per depositary share from the issuance date up to, but not including, the fixed-to-floating rate conversion date; thereafter, dividends will accrue on a floating rate basis equal to 3-month LIBOR plus a fixed spread.

2.Shares may be redeemed prior to our optional redemption date under certain circumstances intended to preserve our qualification as a REIT for U.S federal income tax purposes.

At-the-Market Offering Program

We are authorized by our Board of Directors to enter into agreements with sales agents to publicly offer and sell shares of our common stock in privately negotiated and/or at-the-market transactions from time-to-time up to a maximum aggregate offering price of our common stock. During the nine months ended September 30, 2020, we sold 26.7 million shares of our common stock under the sales agreements for proceeds of $439 million, or $16.46 per common share, net of offering costs. As of September 30, 2020, shares of our common stock with an aggregate offering price of $26 million remained authorized for issuance under this program through June 14, 2021.

Common Stock Repurchase Program

From time-to-time we are authorized by our Board of Directors to repurchase shares of our common stock under certain conditions. In July 2019, our Board of Directors authorized the repurchase of up to $1 billion of our outstanding shares of common stock through December 31, 2020. During the three and nine months ended September 30, 2020, we repurchased 11.0 million and 23.3 million shares, or $154 million and $301 million, respectively, of our common stock for an average repurchase price of $13.95 and $12.92 per common share, respectively, including 0.7 million shares, or $10 million, of share repurchases settling in October 2020 and inclusive of transaction costs. As of September 30, 2020, we had $597 million of common stock remaining available for repurchase. See also Note 11. Subsequent Events for additional information pertaining to our common stock repurchase program.

Accumulated Other Comprehensive Income (Loss)

The following table summarizes changes to accumulated OCI for the three and nine months ended September 30, 2020 and 2019 (in millions):


	Three Months Ended September 30,				Nine Months Ended September 30,
Accumulated Other Comprehensive Income (Loss)	2020		2019		2020		2019
Beginning Balance	$	764	$	(164)	$	97	$	(943)
OCI before reclassifications	70		246		777		1,016
Net loss amounts for available-for-sale securities reclassified from accumulated OCI to realized gain (loss) on sale of investment securities, net	—		—		(40)		9
Ending Balance	$	834	$	82	$	834	$	82

Derivative and Other Hedging Instruments (Tables)

9 Months Ended

Sep. 30, 2020

Derivative [Line Items]

Schedule of Interest Rate Swap Agreement by Receive Index (as a percentage of Notional Amount) [Table Text Block]


Pay Fixed / Receive Variable Interest Rate Swaps by Receive Index (% of Notional Amount)	September 30, 2020		December 31, 2019
SOFR	69	%	3	%
OIS	31	%	86	%
3M LIBOR	—	%	11	%
Total	100	%	100	%

Schedule of Outstanding Derivatives Not Designated as Hedging Instruments

The table below summarizes fair value information about our derivative and other hedging instrument assets/(liabilities) as of September 30, 2020 and December 31, 2019 (in millions):


Derivative and Other Hedging Instruments	Balance Sheet Location	September 30, 2020		December 31, 2019
Interest rate swaps	Derivative assets, at fair value	$	41	$	21
Swaptions	Derivative assets, at fair value	5		126
TBA securities	Derivative assets, at fair value	84		29
U.S. Treasury futures - short	Derivative assets, at fair value	—		14
Total derivative assets, at fair value		$	130	$	190

Interest rate swaps	Derivative liabilities, at fair value	$	—	$	(2)
TBA securities	Derivative liabilities, at fair value	(8)		(4)
U.S. Treasury futures - short	Derivative liabilities, at fair value	(5)		—
Total derivative liabilities, at fair value		$	(13)	$	(6)

U.S. Treasury securities - long	U.S. Treasury securities, at fair value	$	—	$	97
U.S. Treasury securities - short	Obligation to return securities borrowed under reverse repurchase agreements, at fair value	(8,372)		(9,543)
Total U.S. Treasury securities, net at fair value		$	(8,372)	$	(9,446)

Schedule of Interest Rate Swaption Agreements Outstanding


Swaptions	Option					Underlying Payer Swap
Current Option Expiration Date	Cost Basis		Fair Value		Average Months to Current Option Expiration Date 1	Notional Amount		Average Fixed Pay Rate 2	Average Term (Years)
September 30, 2020
≤ 1 year	$	133	$	3	6	$	6,400	2.35%	9.2
> 1 year ≤ 2 years	8		2		17	500		1.87%	10.0
Total	$	141	$	5	7	$	6,900	2.32%	9.3

December 31, 2019
≤ 1 year	$	123	$	80	8	$	5,650	2.26%	9.3
> 1 year ≤ 2 years	53		46		16	3,200		2.50%	10.0
Total	$	176	$	126	11	$	8,850	2.34%	9.5

________________________________

1.As of September 30, 2020 and December 31, 2019, ≤ 1 year notional amount includes $700 million of Bermudan swaptions where the options may be exercised on predetermined dates up to their final exercise date, which is six months prior to the underlying swaps' maturity date.

2.As of September 30, 2020, 71% and 29% of the underlying swap receive rates were tied to 3-Month LIBOR and SOFR, respectively, and, as of December 31, 2019, 100% of the underlying payer swap receive rates were tied to 3-Month LIBOR.

US government securities


U.S. Treasury Securities	September 30, 2020						December 31, 2019
Maturity	Face Amount Long/(Short)		Cost Basis 1		Fair Value		Face Amount Long/(Short)		Cost Basis 1		Fair Value
5 years	$	(425)	$	(425)	$	(426)	$	95	$	95	$	97
7 years	(1,083)		(1,081)		(1,097)		—		—		—
10 years	(6,220)		(6,386)		(6,849)		(9,224)		(9,329)		(9,543)
Total U.S. Treasury securities	$	(7,728)	$	(7,892)	$	(8,372)	$	(9,129)	$	(9,234)	$	(9,446)

________________________________

1.As of September 30, 2020 and December 31, 2019, short U.S. Treasury securities had a weighted average yield of 1.32% and 2.19%, respectively, and, as of December 31, 2019, long U.S. Treasury securities had a weighted average yield of 2.21%.

US Government Futures Securities [Table Text Block]


U.S. Treasury Futures	September 30, 2020								December 31, 2019
Maturity	Notional Amount Long (Short)		Cost Basis		Fair Value		Net Carrying Value 1		Notional Amount Long (Short)		Cost Basis		Fair Value		Net Carrying Value 1
10 years	$	(1,000)	$	(1,390)	$	(1,395)	$	(5)	$	(1,000)	$	(1,298)	$	(1,284)	$	14

________________________________

1.Net carrying value represents the difference between the fair market value and the cost basis (or the forward price to be paid/(received) for the underlying U.S. Treasury security) of the U.S. Treasury futures contract as of period-end and is reported in derivative assets/(liabilities), at fair value in our consolidated balance sheets.

Summary of Long and Short Position of Derivative Instruments


	September 30, 2020								December 31, 2019
TBA Securities by Coupon	Notional Amount Long (Short)		Cost Basis		Fair Value		Net Carrying Value 1		Notional Amount Long (Short)		Cost Basis		Fair Value		Net Carrying Value 1
15-Year TBA securities:
≤ 2.0%	$	10,228	$	10,514	$	10,552	38		$	—	$	—	$	—	$	—
2.5%	866		907		904		(3)		805		811		812		1
3.0%	—		—		—		—		1,059		1,083		1,086		3
3.5%	—		—		—		—		241		250		250		—
4.0%	—		—		—		—		75		78		78		—
Total 15-Year TBA securities	11,094		11,421		11,456		35		2,180		2,222		2,226		4
30-Year TBA securities:
2.0%	11,375		11,694		11,736		42		—		—		—		—
2.5%	5,489		5,752		5,753		1		—		—		—		—
3.0%	395		415		413		(2)		5,008		5,052		5,073		21
3.5%	168		178		178		—		1,226		1,259		1,261		2
4.0%	—		—		—		—		(1,507)		(1,565)		(1,568)		(3)
≥ 4.5%	—		—		—		—		415		436		437		1
Total 30-Year TBA securities, net	17,427		18,039		18,080		41		5,142		5,182		5,203		21
Total TBA securities, net	$	28,521	$	29,460	$	29,536	$	76	$	7,322	$	7,404	$	7,429	$	25

________________________________

1.Net carrying value represents the difference between the fair market value and the cost basis (or the forward price to be paid/(received) for the underlying Agency security) of the TBA contract as of period-end and is reported in derivative assets/(liabilities), at fair value in our consolidated balance sheets.

Schedule Of Outstanding Not Designated As Hedging Instruments

The following table summarizes changes in our derivative and other hedge portfolio and their effect on our consolidated statements of comprehensive income for the three and nine months ended September 30, 2020 and 2019 (in millions):


Derivative and Other Hedging Instruments	Beginning Notional Amount		Additions	Settlement, Termination, Expiration or Exercise	Ending Notional Amount		Gain/(Loss) on Derivative Instruments and Other Securities, Net 1
Three months ended September 30, 2020:
TBA securities, net	$	19,760	80,599	(71,838)	$	28,521	$	283
Interest rate swaps - payer	$	42,075	24,975	(24,075)	$	42,975	140
Payer swaptions	$	9,350	—	(2,450)	$	6,900	(1)
U.S. Treasury securities - short position	$	(7,247)	(2,735)	2,255	$	(7,727)	(15)
U.S. Treasury securities - long position	$	1,132	—	(1,133)	$	(1)	1
U.S. Treasury futures contracts - short position	$	(1,000)	(1,000)	1,000	$	(1,000)	(5)
							$	403
Three months ended September 30, 2019:
TBA securities, net	$	11,043	24,305	(33,381)	$	1,967	$	144
Interest rate swaps - payer	$	74,950	82,625	(75,800)	$	81,775	(482)
Interest rate swaps - receiver	$	—	(175)	175	$	—	—
Payer swaptions	$	4,400	4,500	(250)	$	8,650	(19)
U.S. Treasury securities - short position	$	(7,245)	(98)	2,710	$	(4,633)	(154)
U.S. Treasury securities - long position	$	1,134	353	(1,278)	$	209	5
U.S. Treasury futures contracts - short position	$	(1,650)	(1,000)	1,650	$	(1,000)	(40)
							$	(546)



Nine months ended September 30, 2020:
TBA securities, net	$	7,322	193,535	(172,336)	$	28,521	$	1,196
Interest rate swaps - payer	$	79,075	100,700	(136,800)	$	42,975	(3,034)
Payer swaptions	$	8,850	2,000	(3,950)	$	6,900	(149)
U.S. Treasury securities - short position	$	(9,224)	(12,967)	14,464	$	(7,727)	(1,012)
U.S. Treasury securities - long position	$	95	7,011	(7,107)	$	(1)	102
U.S. Treasury futures contracts - short position	$	(1,000)	(3,000)	3,000	$	(1,000)	(117)
							$	(3,014)
Nine months ended September 30, 2019:
TBA securities, net	$	7,152	70,606	(75,791)	$	1,967	$	390
Interest rate swaps - payer	$	51,625	152,975	(122,825)	$	81,775	(2,097)
Interest rate swaps - receiver	$	—	(175)	175	$	—	—
Payer swaptions	$	3,500	7,150	(2,000)	$	8,650	(71)
U.S. Treasury securities - short position	$	(21,345)	(7,404)	24,116	$	(4,633)	(1,084)
U.S. Treasury securities - long position	$	45	1,776	(1,612)	$	209	11
U.S. Treasury futures contracts - short position	$	(1,650)	(4,300)	4,950	$	(1,000)	(128)
							$	(2,979)

________________________________

1.Amounts exclude $146 million of losses on debt extinguishment for the nine months ended September 30, 2020 (see Note 5) and other miscellaneous gains and losses for all periods presented recognized in gain (loss) on derivative instruments and other securities, net in our consolidated statements of comprehensive income.

Not Designated as Hedging Instrument [Member]

Derivative [Line Items]

Schedule Of Interest Rate Swap Agreement By Remaining Maturity

The following tables summarize certain characteristics of our derivative and other hedging instruments outstanding as of September 30, 2020 and December 31, 2019 (dollars in millions):


	September 30, 2020					December 31, 2019
Pay Fixed / Receive Variable Interest Rate Swaps	Notional Amount		Average Fixed Pay Rate	Average Receive Rate	Average Maturity (Years)	Notional Amount		Average Fixed Pay Rate	Average Receive Rate	Average Maturity (Years)
≤ 3 years	$	8,750	0.04%	0.08%	2.6	$	59,700	1.30%	1.58%	1.6
> 3 to ≤ 5 years	16,750		0.10%	0.08%	4.3	9,850		1.17%	1.55%	3.8
> 5 to ≤ 7 years	9,800		0.21%	0.08%	6.0	5,650		1.34%	1.70%	6.4
> 7 to ≤ 10 years	6,200		0.28%	0.08%	8.8	2,850		1.36%	1.58%	8.9
> 10 years	1,475		0.47%	0.08%	14.4	1,025		1.64%	1.78%	15.4
Total	$	42,975	0.15%	0.08%	5.3	$	79,075	1.29%	1.59%	2.7

Consolidated Statements Of Comprehensive Income - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Dividends declared per common share	$ 0.36	$ 0.48	$ 1.20	$ 1.52
Net gain (loss) on sale of investment securities	$ 346	$ 89	$ 993	$ 281
Unrealized gain (loss) on investment securities measured at fair value through net income, net	(365)	355	511	2,174
(Loss) gain on derivative instruments and other securities, net	400	(548)	(3,139)	(2,986)
Total other (loss) income, net	381	(104)	(1,635)	(531)
Interest income:
Interest income	364	676	1,284	2,074
Interest expense	62	557	622	1,668
Net interest income	302	119	662	406
Other gain (loss), net:
Gain on sale of investment securities, net	346	89	993	281
Unrealized gain (loss) on investment securities measured at fair value through net income, net	(365)	355	511	2,174
Gain (loss) on derivative instruments and other securities, net	400	(548)	(3,139)	(2,986)
Expenses:
Compensation and benefits	13	10	39	31
Other operating expense	8	9	29	27
Total operating expense	21	19	68	58
Net income (loss)	662	(4)	(1,041)	(183)
Dividend on preferred stock	25	13	71	36
Net income (loss) available (attributable) to common stockholders	637	(17)	(1,112)	(219)
Other comprehensive income (loss):
Unrealized gain on investment securities measured at fair value through other comprehensive income, net	(70)	(246)	(737)	(1,025)
Comprehensive income (loss)	732	242	(304)	842
Comprehensive income (loss) available (attributable) to common stockholders	$ 707	$ 229	$ (375)	$ 806
Weighted average number of common shares outstanding - basic	553.2	546.4	553.8	540.3
Weighted average number of common shares outstanding - diluted	554.3	546.4	553.8	540.3
Net income (loss) per common share - basic	$ 1.15	$ (0.03)	$ (2.01)	$ (0.41)
Net income (loss) per common share - diluted	$ 1.15	$ (0.03)	$ (2.01)	$ (0.41)

Stockholders' Equity (Follow-On Equity Offerings) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Class of Stock [Line Items]
Sale of Stock, Price Per Share		$ 16.46
Stock Issued During Period, Shares, New Issues		26.7
Stock Issued During Period, Value, New Issues	$ (103)	$ 439	$ 190

Summary of Significant Accounting Policies Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2020
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Derivatives, Policy [Policy Text Block]	Derivative Instruments We use a variety of derivative instruments to hedge a portion of our exposure to market risks, including interest rate, prepayment, extension and liquidity risks. The objective of our risk management strategy is to reduce fluctuations in net book value over a range of interest rate scenarios. In particular, we attempt to mitigate the risk of the cost of our variable rate liabilities increasing during a period of rising interest rates. The primary instruments that we use are interest rate swaps, options to enter into interest rate swaps ("swaptions"), U.S. Treasury securities and U.S. Treasury futures contracts. We also use forward contracts in the Agency RMBS "to-be-announced" market, or TBA securities, to invest in and finance Agency securities and to periodically reduce our exposure to Agency RMBS. We account for derivative instruments in accordance with ASC Topic 815, Derivatives and Hedging ("ASC 815"). ASC 815 requires an entity to recognize all derivatives as either assets or liabilities in our accompanying consolidated balance sheets and to measure those instruments at fair value. None of our derivative instruments have been designated as hedging instruments for accounting purposes under the provisions of ASC 815, consequently changes in the fair value of our derivative instruments are reported in gain (loss) on derivative instruments and other securities, net in our consolidated statements of comprehensive income. Our derivative agreements generally contain provisions that allow for netting or setting off derivative assets and liabilities with the counterparty; however, we report related assets and liabilities on a gross basis in our consolidated balance sheets. Derivative instruments in a gain position are reported as derivative assets at fair value and derivative instruments in a loss position are reported as derivative liabilities at fair value in our consolidated balance sheets. Changes in fair value of derivative instruments and periodic settlements related to our derivative instruments are recorded in gain (loss) on derivative instruments and other securities, net in our consolidated statements of comprehensive income. Cash receipts and payments related to derivative instruments are classified in our consolidated statements of cash flows according to the underlying nature or purpose of the derivative transaction, generally in the investing section. Interest rate swap agreements We use interest rate swaps to economically hedge the variable cash flows associated with our borrowings made under repurchase agreements. Under our interest rate swap agreements, we typically pay a fixed rate and receive a floating rate ("payer swaps") based on a short-term benchmark rate, such as the Secured Overnight Financing Rate ("SOFR"), Overnight Index Swap Rate ("OIS") or three-month London Interbank Offered Rate ("LIBOR"). Our interest rate swaps typically have terms from one to 10 years but may extend up to 20 years or more. Our interest rate swaps are centrally cleared through a registered commodities exchange. The clearing exchange requires that we post an "initial margin" amount determined by the exchange, which is generally intended to be set at a level sufficient to protect the exchange from the interest rate swap's maximum estimated single-day price movement. We also exchange daily settlements of "variation margin" based upon changes in fair value, as measured by the exchange. Pursuant to rules governing central clearing activities, we recognize variation margin settlements as a direct reduction of the carrying value of the interest rate swap asset or liability. Interest rate swaptions We purchase interest rate swaptions to help mitigate the potential impact of larger, more rapid changes in interest rates on the performance of our investment portfolio. Interest rate swaptions provide us the option to enter into an interest rate swap agreement for a predetermined notional amount, stated term and pay and receive interest rates in the future. Our interest rate swaption agreements are not subject to central clearing. The premium paid for interest rate swaptions is reported as an asset in our consolidated balance sheets. The difference between the premium paid and the fair value of the swaption is reported in gain (loss) on derivative instruments and other securities, net in our consolidated statements of comprehensive income. If a swaption expires unexercised, the realized loss on the swaption would be equal to the premium paid. If we sell or exercise a swaption, the realized gain or loss on the swaption would be equal to the difference between the cash or the fair value of the underlying interest rate swap and the premium paid. TBA securities A TBA security is a forward contract for the purchase or sale of Agency RMBS at a predetermined price, face amount, issuer, coupon and stated maturity on an agreed-upon future date. The specific Agency RMBS to be delivered into the contract are not known until shortly before the settlement date. We may choose, prior to settlement, to move the settlement of these securities out to a later date by entering into an offsetting TBA position, net settling the offsetting positions for cash, and simultaneously purchasing or selling a similar TBA contract for a later settlement date (together referred to as a "dollar roll transaction"). The Agency securities purchased or sold for a forward settlement date are typically priced at a discount to equivalent securities settling in the current month. This difference, or "price drop," is the economic equivalent of interest income on the underlying Agency securities, less an implied funding cost, over the forward settlement period (referred to as "dollar roll income"). Consequently, forward purchases of Agency securities and dollar roll transactions represent a form of off-balance sheet financing. We account for TBA contracts as derivative instruments since either the TBA contracts do not settle in the shortest period of time possible or we cannot assert that it is probable at inception and throughout the term of the TBA contract that we will physically settle the contract on the settlement date. We account for TBA dollar roll transactions as a series of derivative transactions. U.S. Treasury securities We use U.S. Treasury securities and U.S. Treasury futures contracts to mitigate the potential impact of changes in interest rates on the performance of our portfolio. We borrow U.S. Treasury securities under reverse repurchase agreements to cover short sales of U.S. Treasury securities. We account for these as securities borrowing transactions and recognize an obligation to return the borrowed securities at fair value on our accompanying consolidated balance sheets based on the value of the underlying U.S. Treasury security as of the reporting date. Gains and losses associated with U.S. Treasury securities and U.S. Treasury futures contracts are recognized in gain (loss) on derivative instruments and other securities, net in our consolidated statements of comprehensive income.
Investment, Policy [Policy Text Block]	Investment Securities Agency RMBS consist of residential mortgage pass-through securities and collateralized mortgage obligations ("CMOs") guaranteed by the Federal National Mortgage Association ("Fannie Mae"), Federal Home Loan Mortgage Corporation ("Freddie Mac," and together with Fannie Mae, the "GSEs") or the Government National Mortgage Association ("Ginnie Mae"). CRT securities are risk sharing instruments issued by the GSEs, and similarly structured transactions issued by third-party market participants, that synthetically transfer a portion of the risk associated with credit losses within pools of conventional residential mortgage loans from the GSEs and/or third parties to private investors. Unlike Agency RMBS, full repayment of the original principal balance of CRT securities is not guaranteed by a GSE or U.S. Government agency; rather, "credit risk transfer" is achieved by writing down the outstanding principal balance of the CRT securities if credit losses on a related pool of loans exceed certain thresholds. By reducing the amount that they are obligated to repay to holders of CRT securities, the GSEs and/or other third parties offset credit losses on the related loans. Non-Agency RMBS and CMBS (together, "Non-Agency MBS") are backed by residential and commercial mortgage loans, respectively, packaged and securitized by a private institution, such as a commercial bank. Non-Agency MBS typically benefit from credit enhancements derived from structural elements, such as subordination, overcollateralization or insurance, but nonetheless carry a higher level of credit exposure than Agency RMBS. All of our securities are reported at fair value on our consolidated balance sheet. Accounting Standards Codification ("ASC") Topic 320, Investments—Debt and Equity Securities, requires that at the time of purchase, we designate a security as held-to-maturity, available-for-sale or trading, depending on our ability and intent to hold such security to maturity. Alternatively, we may elect the fair value option of accounting for securities pursuant to ASC Topic 825, Financial Instruments. Prior to fiscal year 2017, we primarily designated our investment securities as available-for-sale. On January 1, 2017, we began electing the fair value option of accounting for all investment securities newly acquired after such date. Unrealized gains and losses on securities classified as available-for-sale are reported in accumulated other comprehensive income ("OCI"), whereas unrealized gains and losses on securities for which we elected the fair value option, or are classified as trading, are reported in net income through other gain (loss). Upon the sale of a security designated as available-for-sale, we determine the cost of the security and the amount of unrealized gain or loss to reclassify out of accumulated OCI into earnings based on the specific identification method. In our view, the election of the fair value option simplifies the accounting for investment securities and more appropriately reflects the results of our operations for a reporting period by presenting the fair value changes for these assets in a manner consistent with the presentation and timing of the fair value changes for our derivative instruments. We generally recognize gains or losses through net income on available-for-sale securities only if the security is sold; however, if the fair value of a security declines below its amortized cost and we determine that it is more likely than not that we will incur a realized loss on the security when we sell the asset, we will recognize the difference between the amortized cost and the fair in net income as a component of other gain (loss). Since all of our available-for-sale designated securities consist of Agency RMBS, we do not have an allowance for credit losses. We have not recognized impairment losses on our available-for-sale securities through net income for the periods presented in our consolidated financial statements.
Interest Income [Policy Text Block]	Interest Income Interest income is accrued based on the outstanding principal amount of the investment securities and their contractual terms. Premiums or discounts associated with the purchase of Agency RMBS and non-Agency MBS of high credit quality are amortized or accreted into interest income, respectively, over the projected lives of the securities, including contractual payments and estimated prepayments, using the effective interest method in accordance with ASC Subtopic 310-20, Receivables—Nonrefundable Fees and Other Costs. We estimate long-term prepayment speeds of our mortgage securities using a third-party service and market data. The third-party service provider estimates prepayment speeds using models that incorporate the forward yield curve, primary to secondary mortgage rate spreads, current mortgage rates, mortgage rates of the outstanding loans, age and size of the outstanding loans, loan-to-value ratios, interest rate volatility and other factors. We review the prepayment speeds estimated by the third-party service for reasonableness with consideration given to both historical prepayment speeds and current market conditions. If based on our assessment, we believe that the third-party model does not fully reflect our expectations of the current prepayment landscape, such as during periods of elevated market uncertainty or unique market conditions, we may make adjustments to the models. We review our actual and anticipated prepayment experience on at least a quarterly basis and effective yields are recalculated when differences arise between (i) our previous estimate of future prepayments and (ii) actual prepayments to date and our current estimate of future prepayments. We are required to record an adjustment in the current period to premium amortization / discount accretion for the cumulative effect of the difference in the effective yields as if the recalculated yield had been in place as of the security's acquisition date through the reporting date. At the time we purchase CRT securities and non-Agency MBS that are not of high credit quality, we determine an effective yield based on our estimate of the timing and amount of future cash flows and our cost basis. Our initial cash flow estimates for these investments are based on our observations of current information and events and include assumptions related to interest rates, prepayment rates and the impact of default and severity rates on the timing and amount of credit losses. On at least a quarterly basis, we review the estimated cash flows and make appropriate adjustments based on inputs and analysis received from external sources, internal models, and our judgment regarding such inputs and other factors. Any resulting changes in effective yield are recognized prospectively based on the current amortized cost of the investment adjusted for credit impairments, if any.

Subsequent Event (Details) - USD ($)			3 Months Ended		9 Months Ended
Subsequent Event (Details) - USD ($)	Oct. 08, 2020	Feb. 11, 2020	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Oct. 22, 2020	Dec. 31, 2019	Oct. 03, 2019	Jul. 31, 2019
Subsequent Event [Line Items]
Preferred Stock, Liquidation Preference, Value			$ 1,538,000,000		$ 1,538,000,000			$ 963,000,000
Preferred Stock D, Value, Issued			227,000,000		227,000,000
Preferred Stock E, Value, Issued									$ 390,000,000
Preferred Stock E, Liquidation Preference, Value									$ 403,000,000
Dividends, Preferred Stock, Cash			$ 25,000,000	$ 13,000,000	$ 71,000,000	$ 36,000,000
Common Stock, Dividends, Per Share, Declared			$ 0.36	$ 0.48	$ 1.20	$ 1.52
Stock Issued During Period, Shares, New Issues					26,700,000
Stock Issued During Period, Value, New Issues				$ (103,000,000)	$ 439,000,000	$ 190,000,000
Sale of Stock, Price Per Share			$ 16.46		$ 16.46
Stock Repurchase Program, Authorized Amount										$ 1,000,000,000
Stock Repurchased During Period, Shares			10,300,000		22,500,000
Stock Repurchased During Period, Value			$ 144,000,000		$ 291,000,000
Stock Repurchased During Period, Average Repurchase Price (in dollars per share)			13.95		$ 12.92
Subsequent Event [Member]
Subsequent Event [Line Items]
Common Stock, Dividends, Per Share, Declared	$ 0.12
Stock Repurchase Program, Authorized Amount							$ 1,000,000,000
Common Stock [Member]
Subsequent Event [Line Items]
Stock Issued During Period, Shares, New Issues					26,700,000	11,400,000
Stock Issued During Period, Value, New Issues					$ 1,000,000
Stock Repurchased During Period, Shares						6,900,000
Stock Repurchased During Period, Value			$ 1,000,000		$ 1,000,000
Series F Preferred Stock [Member]
Subsequent Event [Line Items]
Preferred Stock, Liquidation Preference, Value		$ 575,000,000
Preferred Stock, Dividend Rate, Percentage		6.125%
Preferred Stock, Shares Issued			23,000		23,000
Preferred Stock, Capital Shares Reserved for Future Issuance			23,000		23,000
Depositary Share [Member]
Subsequent Event [Line Items]
Preferred Stock, Shares Issued			61,500,000		61,500,000
Depositary Share [Member] \| Series F Preferred Stock [Member]
Subsequent Event [Line Items]
Preferred Stock, Shares Issued		23,000,000.0

Summary of Significant Accounting Policies Variable Interest Entities (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Variable Interest Entity [Line Items]
Other Long-term Debt	$ 192	$ 228

Summary of Significant Accounting Policies	9 Months Ended
Summary of Significant Accounting Policies	Sep. 30, 2020
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Investment Securities Agency RMBS consist of residential mortgage pass-through securities and collateralized mortgage obligations ("CMOs") guaranteed by the Federal National Mortgage Association ("Fannie Mae"), Federal Home Loan Mortgage Corporation ("Freddie Mac," and together with Fannie Mae, the "GSEs") or the Government National Mortgage Association ("Ginnie Mae"). CRT securities are risk sharing instruments issued by the GSEs, and similarly structured transactions issued by third-party market participants, that synthetically transfer a portion of the risk associated with credit losses within pools of conventional residential mortgage loans from the GSEs and/or third parties to private investors. Unlike Agency RMBS, full repayment of the original principal balance of CRT securities is not guaranteed by a GSE or U.S. Government agency; rather, "credit risk transfer" is achieved by writing down the outstanding principal balance of the CRT securities if credit losses on a related pool of loans exceed certain thresholds. By reducing the amount that they are obligated to repay to holders of CRT securities, the GSEs and/or other third parties offset credit losses on the related loans. Non-Agency RMBS and CMBS (together, "Non-Agency MBS") are backed by residential and commercial mortgage loans, respectively, packaged and securitized by a private institution, such as a commercial bank. Non-Agency MBS typically benefit from credit enhancements derived from structural elements, such as subordination, overcollateralization or insurance, but nonetheless carry a higher level of credit exposure than Agency RMBS. All of our securities are reported at fair value on our consolidated balance sheet. Accounting Standards Codification ("ASC") Topic 320, Investments—Debt and Equity Securities, requires that at the time of purchase, we designate a security as held-to-maturity, available-for-sale or trading, depending on our ability and intent to hold such security to maturity. Alternatively, we may elect the fair value option of accounting for securities pursuant to ASC Topic 825, Financial Instruments. Prior to fiscal year 2017, we primarily designated our investment securities as available-for-sale. On January 1, 2017, we began electing the fair value option of accounting for all investment securities newly acquired after such date. Unrealized gains and losses on securities classified as available-for-sale are reported in accumulated other comprehensive income ("OCI"), whereas unrealized gains and losses on securities for which we elected the fair value option, or are classified as trading, are reported in net income through other gain (loss). Upon the sale of a security designated as available-for-sale, we determine the cost of the security and the amount of unrealized gain or loss to reclassify out of accumulated OCI into earnings based on the specific identification method. In our view, the election of the fair value option simplifies the accounting for investment securities and more appropriately reflects the results of our operations for a reporting period by presenting the fair value changes for these assets in a manner consistent with the presentation and timing of the fair value changes for our derivative instruments. We generally recognize gains or losses through net income on available-for-sale securities only if the security is sold; however, if the fair value of a security declines below its amortized cost and we determine that it is more likely than not that we will incur a realized loss on the security when we sell the asset, we will recognize the difference between the amortized cost and the fair in net income as a component of other gain (loss). Since all of our available-for-sale designated securities consist of Agency RMBS, we do not have an allowance for credit losses. We have not recognized impairment losses on our available-for-sale securities through net income for the periods presented in our consolidated financial statements. Interest Income Interest income is accrued based on the outstanding principal amount of the investment securities and their contractual terms. Premiums or discounts associated with the purchase of Agency RMBS and non-Agency MBS of high credit quality are amortized or accreted into interest income, respectively, over the projected lives of the securities, including contractual payments and estimated prepayments, using the effective interest method in accordance with ASC Subtopic 310-20, Receivables—Nonrefundable Fees and Other Costs. We estimate long-term prepayment speeds of our mortgage securities using a third-party service and market data. The third-party service provider estimates prepayment speeds using models that incorporate the forward yield curve, primary to secondary mortgage rate spreads, current mortgage rates, mortgage rates of the outstanding loans, age and size of the outstanding loans, loan-to-value ratios, interest rate volatility and other factors. We review the prepayment speeds estimated by the third-party service for reasonableness with consideration given to both historical prepayment speeds and current market conditions. If based on our assessment, we believe that the third-party model does not fully reflect our expectations of the current prepayment landscape, such as during periods of elevated market uncertainty or unique market conditions, we may make adjustments to the models. We review our actual and anticipated prepayment experience on at least a quarterly basis and effective yields are recalculated when differences arise between (i) our previous estimate of future prepayments and (ii) actual prepayments to date and our current estimate of future prepayments. We are required to record an adjustment in the current period to premium amortization / discount accretion for the cumulative effect of the difference in the effective yields as if the recalculated yield had been in place as of the security's acquisition date through the reporting date. At the time we purchase CRT securities and non-Agency MBS that are not of high credit quality, we determine an effective yield based on our estimate of the timing and amount of future cash flows and our cost basis. Our initial cash flow estimates for these investments are based on our observations of current information and events and include assumptions related to interest rates, prepayment rates and the impact of default and severity rates on the timing and amount of credit losses. On at least a quarterly basis, we review the estimated cash flows and make appropriate adjustments based on inputs and analysis received from external sources, internal models, and our judgment regarding such inputs and other factors. Any resulting changes in effective yield are recognized prospectively based on the current amortized cost of the investment adjusted for credit impairments, if any. Repurchase Agreements We finance the acquisition of securities for our investment portfolio primarily through repurchase transactions under master repurchase agreements. Pursuant to ASC Topic 860, Transfers and Servicing, we account for repurchase transactions as collateralized financing transactions, which are carried at their contractual amounts (cost), plus accrued interest. Our repurchase agreements typically have maturities of less than one year but may extend up to five years or more. Reverse Repurchase Agreements and Obligation to Return Securities Borrowed under Reverse Repurchase Agreements We borrow securities to cover short sales of U.S. Treasury securities through reverse repurchase transactions under our master repurchase agreements (see Derivative Instruments below). We account for these as securities borrowing transactions and recognize an obligation to return the borrowed securities at fair value on the balance sheet based on the value of the underlying borrowed securities as of the reporting date. We may also enter into reverse repurchase agreements to earn a yield on excess cash balances. The securities received as collateral in connection with our reverse repurchase agreements mitigate our credit risk exposure to counterparties. Our reverse repurchase agreements typically have maturities of 30 days or less. Derivative Instruments We use a variety of derivative instruments to hedge a portion of our exposure to market risks, including interest rate, prepayment, extension and liquidity risks. The objective of our risk management strategy is to reduce fluctuations in net book value over a range of interest rate scenarios. In particular, we attempt to mitigate the risk of the cost of our variable rate liabilities increasing during a period of rising interest rates. The primary instruments that we use are interest rate swaps, options to enter into interest rate swaps ("swaptions"), U.S. Treasury securities and U.S. Treasury futures contracts. We also use forward contracts in the Agency RMBS "to-be-announced" market, or TBA securities, to invest in and finance Agency securities and to periodically reduce our exposure to Agency RMBS. We account for derivative instruments in accordance with ASC Topic 815, Derivatives and Hedging ("ASC 815"). ASC 815 requires an entity to recognize all derivatives as either assets or liabilities in our accompanying consolidated balance sheets and to measure those instruments at fair value. None of our derivative instruments have been designated as hedging instruments for accounting purposes under the provisions of ASC 815, consequently changes in the fair value of our derivative instruments are reported in gain (loss) on derivative instruments and other securities, net in our consolidated statements of comprehensive income. Our derivative agreements generally contain provisions that allow for netting or setting off derivative assets and liabilities with the counterparty; however, we report related assets and liabilities on a gross basis in our consolidated balance sheets. Derivative instruments in a gain position are reported as derivative assets at fair value and derivative instruments in a loss position are reported as derivative liabilities at fair value in our consolidated balance sheets. Changes in fair value of derivative instruments and periodic settlements related to our derivative instruments are recorded in gain (loss) on derivative instruments and other securities, net in our consolidated statements of comprehensive income. Cash receipts and payments related to derivative instruments are classified in our consolidated statements of cash flows according to the underlying nature or purpose of the derivative transaction, generally in the investing section. Interest rate swap agreements We use interest rate swaps to economically hedge the variable cash flows associated with our borrowings made under repurchase agreements. Under our interest rate swap agreements, we typically pay a fixed rate and receive a floating rate ("payer swaps") based on a short-term benchmark rate, such as the Secured Overnight Financing Rate ("SOFR"), Overnight Index Swap Rate ("OIS") or three-month London Interbank Offered Rate ("LIBOR"). Our interest rate swaps typically have terms from one to 10 years but may extend up to 20 years or more. Our interest rate swaps are centrally cleared through a registered commodities exchange. The clearing exchange requires that we post an "initial margin" amount determined by the exchange, which is generally intended to be set at a level sufficient to protect the exchange from the interest rate swap's maximum estimated single-day price movement. We also exchange daily settlements of "variation margin" based upon changes in fair value, as measured by the exchange. Pursuant to rules governing central clearing activities, we recognize variation margin settlements as a direct reduction of the carrying value of the interest rate swap asset or liability. Interest rate swaptions We purchase interest rate swaptions to help mitigate the potential impact of larger, more rapid changes in interest rates on the performance of our investment portfolio. Interest rate swaptions provide us the option to enter into an interest rate swap agreement for a predetermined notional amount, stated term and pay and receive interest rates in the future. Our interest rate swaption agreements are not subject to central clearing. The premium paid for interest rate swaptions is reported as an asset in our consolidated balance sheets. The difference between the premium paid and the fair value of the swaption is reported in gain (loss) on derivative instruments and other securities, net in our consolidated statements of comprehensive income. If a swaption expires unexercised, the realized loss on the swaption would be equal to the premium paid. If we sell or exercise a swaption, the realized gain or loss on the swaption would be equal to the difference between the cash or the fair value of the underlying interest rate swap and the premium paid. TBA securities A TBA security is a forward contract for the purchase or sale of Agency RMBS at a predetermined price, face amount, issuer, coupon and stated maturity on an agreed-upon future date. The specific Agency RMBS to be delivered into the contract are not known until shortly before the settlement date. We may choose, prior to settlement, to move the settlement of these securities out to a later date by entering into an offsetting TBA position, net settling the offsetting positions for cash, and simultaneously purchasing or selling a similar TBA contract for a later settlement date (together referred to as a "dollar roll transaction"). The Agency securities purchased or sold for a forward settlement date are typically priced at a discount to equivalent securities settling in the current month. This difference, or "price drop," is the economic equivalent of interest income on the underlying Agency securities, less an implied funding cost, over the forward settlement period (referred to as "dollar roll income"). Consequently, forward purchases of Agency securities and dollar roll transactions represent a form of off-balance sheet financing. We account for TBA contracts as derivative instruments since either the TBA contracts do not settle in the shortest period of time possible or we cannot assert that it is probable at inception and throughout the term of the TBA contract that we will physically settle the contract on the settlement date. We account for TBA dollar roll transactions as a series of derivative transactions. U.S. Treasury securities We use U.S. Treasury securities and U.S. Treasury futures contracts to mitigate the potential impact of changes in interest rates on the performance of our portfolio. We borrow U.S. Treasury securities under reverse repurchase agreements to cover short sales of U.S. Treasury securities. We account for these as securities borrowing transactions and recognize an obligation to return the borrowed securities at fair value on our accompanying consolidated balance sheets based on the value of the underlying U.S. Treasury security as of the reporting date. Gains and losses associated with U.S. Treasury securities and U.S. Treasury futures contracts are recognized in gain (loss) on derivative instruments and other securities, net in our consolidated statements of comprehensive income. Recent Accounting Pronouncements In June 2016 the Financial Account Standards Board ("FASB") issued Accounting Standards Update 2016-13, Financial Instruments - Credit Losses (Topic 326), which replaces the incurred loss impairment methodology in prior GAAP with a methodology that better reflects expected credit losses. For financial instruments carried at amortized cost, impairment will be measured as a current estimate of expected lifetime credit losses. For available-for-sale investment securities with changes in fair value recorded in accumulated other comprehensive income, the FASB made targeted improvements eliminating the write-down of available-for-sale securities under the "other-than-temporary" impairment model replacing it with an allowance for credit loss model. We adopted ASU 2016-13 effective January 1, 2020, which had no material effect on our financial results. We consider the applicability and impact of all ASUs issued by the FASB. There are no unadopted ASUs that are expected to have a significant impact on our consolidated financial statements when adopted or other recently adopted ASUs that had a significant impact on our consolidated financial statements upon adoption.

Repurchase Agreements And Reverse Repurchase Agreements

9 Months Ended

Sep. 30, 2020

Disclosure of Repurchase Agreements [Abstract]

Repurchase Agreements And Other Debt

Repurchase Agreements and Reverse Repurchase Agreements

Repurchase Agreements

We pledge our securities as collateral under our borrowings structured as repurchase agreements with financial institutions. Amounts available to be borrowed are dependent upon the fair value of the securities pledged as collateral, which

fluctuates with changes in interest rates, type of security and liquidity conditions within the banking, mortgage finance and real estate industries. If the fair value of our pledged securities declines, lenders will typically require us to post additional collateral or pay down borrowings to re-establish agreed upon collateral requirements, referred to as "margin calls." Similarly, if the fair value of our pledged securities increases, lenders may release collateral back to us. As of September 30, 2020, we had met all margin call requirements. For additional information regarding our pledged assets, please refer to Note 7.

As of September 30, 2020 and December 31, 2019, we had $54.6 billion and $89.2 billion, respectively, of repurchase agreements outstanding used to fund our investment portfolio and temporary holdings of U.S. Treasury securities. The terms and conditions of our repurchase agreements are typically negotiated on a transaction-by-transaction basis. Our repurchase agreements with original maturities greater than one year may have floating interest rates based on an index plus or minus a fixed spread. The following table summarizes our borrowings under repurchase agreements by their remaining maturities as of September 30, 2020 and December 31, 2019 (dollars in millions):


	September 30, 2020					December 31, 2019
Remaining Maturity	Repurchase Agreements		Weighted Average Interest Rate		Weighted Average Days to Maturity	Repurchase Agreements		Weighted Average Interest Rate		Weighted Average Days to Maturity
Agency repo:
≤ 1 month	$	28,119	0.21	%	10	$	56,664	2.19	%	10
> 1 to ≤ 3 months	12,906		0.21	%	50	20,761		2.01	%	53
> 3 to ≤ 6 months	7,642		1.27	%	104	5,683		2.19	%	100
> 6 to ≤ 9 months	5,041		0.32	%	216	1,500		2.66	%	182
> 9 to ≤ 12 months	658		0.62	%	282	2,152		2.41	%	351
> 12 to ≤ 24 months	—		—	%	—	625		2.38	%	411
> 24 to ≤ 36 months	—		—	%	—	1,700		2.45	%	833
Total Agency repo	54,366		0.37	%	55	89,085		2.17	%	55
U.S. Treasury repo:
> 1 day to ≤ 1 month	200		0.10	%	1	97		1.63	%	2
Total	$	54,566	0.37	%	55	$	89,182	2.17	%	55

As of September 30, 2020 and December 31, 2019, $8.9 billion and $17.0 billion, respectively, of our repurchase agreements had a remaining maturity of one business day and none of our repurchase agreements were due on demand. As of September 30, 2020, we had $1.5 billion of forward commitments to enter into repurchase agreements, with a weighted average forward start date of 93 days and a weighted average interest rate of 0.25%. As of December 31, 2019, we had $4.5 billion of forward commitments to enter into repurchase agreements, with a weighted average forward start date of 12 days and a weighted average interest rate of 1.60%. As of September 30, 2020 and December 31, 2019, 48% and 40%, respectively, of our repurchase agreement funding was sourced through our wholly-owned captive broker-dealer subsidiary, Bethesda Securities, LLC ("BES"). Amounts sourced through BES include funding from the General Collateral Finance Repo service ("GCF Repo") offered by the Fixed Income Clearing Corporation ("FICC"), which totaled 48% and 38% of our repurchase agreement funding outstanding as of September 30, 2020 and December 31, 2019, respectively.

During the nine months ended September 30, 2020, we terminated $3.7 billion of repurchase agreements with a weighted average interest rate of 2.11% and a weighted average remaining maturity of 2.2 years. The terminated agreements were replaced with shorter duration repurchase agreements at lower prevailing market rates. We recognized losses on debt extinguishment of $146 million in other gain (loss), net for the nine months ended September 30, 2020 associated with the terminated repurchase agreements. We did not terminate any repurchase agreements during the three months ended September 30, 2020 or the prior year periods.

Reverse Repurchase Agreements

As of September 30, 2020 and December 31, 2019, we had $8.6 billion and $10.2 billion, respectively, of reverse repurchase agreements outstanding used primarily to borrow securities to cover short sales of U.S. Treasury securities, for which we had associated obligations to return borrowed securities at fair value of $8.4 billion and $9.5 billion, respectively. As of September 30, 2020 and December 31, 2019, $3.6 billion and $5.4 billion, respectively, of our reverse repurchase agreements were with the FICC sourced through BES.

Stockholders' Equity (At-the-Market Offering Program) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common Stock, Shares Authorized		$ 26
Stock Issued During Period, Shares, New Issues		26.7
Stock Issued During Period, Value, New Issues	$ (103)	$ 439	$ 190
Sale of Stock, Price Per Share		$ 16.46
Common Stock At The Market Sale Agreement [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock Issued During Period, Value, New Issues		$ 439

Derivative and Other Hedging Instruments (Effect Of Derivative Instruments Not Designated As Hedges On Comprehensive Income Statement) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Jun. 30, 2020	Dec. 31, 2019	Jun. 30, 2019	Dec. 31, 2018
Changes in Derivative and Other Hedge Portfolio [Roll Forward]
Amount Gain/(Loss) Recognized in Income on Derivatives	$ 403	$ (546)	$ (3,014)	$ (2,979)
Interest rate swap - receiver [Member]
Changes in Derivative and Other Hedge Portfolio [Roll Forward]
Additions		175		175
Settlement, Expirations or Exercise		(175)		(175)
Amount Gain/(Loss) Recognized in Income on Derivatives		0		0
Interest Rate Swaption [Member]
Changes in Derivative and Other Hedge Portfolio [Roll Forward]
Notional Amount	(6,900)	(8,650)	(6,900)	(8,650)	$ (9,350)	$ (8,850)	$ (4,400)
Additions	0	(4,500)	(2,000)	(7,150)
Settlement, Expirations or Exercise	2,450	250	3,950	2,000
Notional Amount	(6,900)		(6,900)
Amount Gain/(Loss) Recognized in Income on Derivatives	(1)	(19)	(149)	(71)
TBA and Forward Settling Agency Securities [Member]
Changes in Derivative and Other Hedge Portfolio [Roll Forward]
Notional Amount	(28,521)	(1,967)	(28,521)	(1,967)	(19,760)	(7,322)	(11,043)	$ (7,152)
Additions	(80,599)	(24,305)	(193,535)	(70,606)
Settlement, Expirations or Exercise				75,791
Amount Gain/(Loss) Recognized in Income on Derivatives	283	144	1,196	390
Purchases Of TBAs And Forward Settling Agency Securities [Member]
Changes in Derivative and Other Hedge Portfolio [Roll Forward]
Settlement, Expirations or Exercise	71,838	33,381	172,336
Interest Rate Swap [Member]
Changes in Derivative and Other Hedge Portfolio [Roll Forward]
Additions	(24,975)	(82,625)	(100,700)	(152,975)
Settlement, Expirations or Exercise	24,075	75,800	136,800	122,825
Notional Amount	(42,975)		(42,975)
Amount Gain/(Loss) Recognized in Income on Derivatives	140	(482)	(3,034)	(2,097)
US Treasury Securities [Member]
Changes in Derivative and Other Hedge Portfolio [Roll Forward]
Amount Gain/(Loss) Recognized in Income on Derivatives	(5)	(40)	(117)	(128)
Not Designated as Hedging Instrument [Member] \| Interest rate swap - receiver [Member]
Changes in Derivative and Other Hedge Portfolio [Roll Forward]
Notional Amount		0		0			0	0
Not Designated as Hedging Instrument [Member] \| Interest Rate Swaption [Member]
Changes in Derivative and Other Hedge Portfolio [Roll Forward]
Notional Amount								(3,500)
Not Designated as Hedging Instrument [Member] \| Interest Rate Swap [Member]
Changes in Derivative and Other Hedge Portfolio [Roll Forward]
Notional Amount	(42,975)	(81,775)	(42,975)	(81,775)	(42,075)	(79,075)	(74,950)	(51,625)
Short [Member] \| US Treasury Securities [Member]
Changes in Derivative and Other Hedge Portfolio [Roll Forward]
Notional Amount	(7,727)	(4,633)	(7,727)	(4,633)	(7,247)	(9,224)	(7,245)	(21,345)
Additions	(2,735)	(98)	(12,967)	(7,404)
Settlement, Expirations or Exercise	(2,255)	(2,710)	(14,464)	24,116
Amount Gain/(Loss) Recognized in Income on Derivatives	(15)	(154)	(1,012)	(1,084)
Long [Member] \| US Treasury Securities [Member]
Changes in Derivative and Other Hedge Portfolio [Roll Forward]
Amount Gain/(Loss) Recognized in Income on Derivatives	1	5	102	11
Debt Securities, Trading, and Equity Securities, FV-NI	(1)	(209)	(1)	(209)	(1,132)	(95)	(1,134)	(45)
Trading Securities Added During the Period	0	353	7,011	1,776
Notional Amount Of Trading Securities Settlement Expiration During The Period	(1,133)	(1,278)	(7,107)	(1,612)
Future [Member] \| Short [Member] \| US Treasury Securities [Member]
Changes in Derivative and Other Hedge Portfolio [Roll Forward]
Notional Amount	(1,000)	(1,000)	(1,000)	(1,000)	$ (1,000)	$ (1,000)	$ (1,650)	$ (1,650)
Additions	1,000	1,000	3,000	(4,300)
Settlement, Expirations or Exercise	$ (1,000)	$ (1,650)	$ (3,000)	$ 4,950

Investment Securities (Narrative) (Details) - USD ($) $ in Millions	6 Months Ended	9 Months Ended
	Jun. 30, 2020	Sep. 30, 2020	Dec. 31, 2019
Debt Securities, Available-for-sale [Line Items]
Mortgage-backed Securities Available-for-sale, Fair Value Disclosure		$ 68,000	$ 100,400
Weighted average expected constant prepayment rate	10.80%	15.90%
Debt, at fair value		$ (192)	(228)
Agency Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Unamortized premium balance		2,600	3,100
TBA securities Fifteen Year and Thirty Year Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Net long TBA position, at fair value		29,500	7,400
TBA, net carrying value		$ 76	$ 25

Stockholders' Equity (Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Other Comprehensive Income (Loss), Securities, Available-for-Sale, Unrealized Holding Gain (Loss) Arising During Period, after Tax	$ 70	$ 246	$ 737	$ 1,025
Agency Securities [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning OCI Balance	764	(164)	97	(943)
Other Comprehensive Income (Loss), Securities, Available-for-Sale, Unrealized Holding Gain (Loss) Arising During Period, after Tax	70	246	777	1,016
Amounts reclassified from accumulated OCI	0	0	(40)	9
Ending OCI Balance	$ 834	$ 82	$ 834	$ 82

Summary of Significant Accounting Policies (Details)	9 Months Ended
Summary of Significant Accounting Policies (Details)	Sep. 30, 2020
Derivative [Line Items]
Required Annual Distribution of Taxable Net Income	90.00%

Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Statement of Cash Flows [Abstract]
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	$ 2,414,000	$ 1,640,000
Operating activities:
Net income (loss)	(1,041,000)	(183,000)
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization of premiums and discounts on mortgage-backed securities, net	816,000	517,000
Stock based compensation	12,000	8,000
Gain on sale of investment securities, net	(993,000)	(281,000)
Unrealized gain on investment securities measured at fair value through net income, net	(511,000)	(2,174,000)
Loss on derivative instruments and other securities, net	3,139,000	2,986,000
(Increase) decrease in other assets	104,000	(35,000)
Decrease in accounts payable and other accrued liabilities	(189,000)	(31,000)
Net cash provided by operating activities	1,337,000	807,000
Investing activities:
Purchases of Agency mortgage-backed securities	(44,753,000)	(37,199,000)
Purchases of credit risk transfer and non-Agency securities	(609,000)	(1,233,000)
Proceeds from sale of Agency mortgage-backed securities	68,920,000	17,620,000
Proceeds from sale of credit risk transfer and non-Agency securities	838,000	1,130,000
Principal collections on Agency mortgage-backed securities	12,635,000	8,508,000
Principal collections on credit risk transfer and non-Agency securities	115,000	15,000
Payments on U.S. Treasury securities	(22,090,000)	(26,169,000)
Proceeds from U.S. Treasury securities	20,112,000	8,313,000
Net proceeds from reverse repurchase agreements	1,590,000	16,014,000
Net payments on derivative instruments	(2,260,000)	(1,990,000)
Net cash provided by (used in) investing activities	34,498,000	(14,991,000)
Financing activities:
Proceeds from repurchase arrangements	2,651,280,000	3,251,916,000
Payments on repurchase agreements	(2,685,896,000)	(3,237,021,000)
Payments on debt of consolidated variable interest entities	(44,000)	(42,000)
Net proceeds from preferred stock issuance	(557,000)	(227,000)
Net proceeds from common stock issuance	439,000	190,000
Payments for common stock repurchases	(291,000)	(103,000)
Cash dividends paid	(748,000)	(863,000)
Net cash provided by (used in) financing activities	(34,703,000)	14,304,000
Net change in cash and cash equivalents	1,132,000	$ 120,000
Cash and cash equivalents at end of period	$ 857,000

Derivative and Other Hedging Instruments (Fair Value Information) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Jun. 30, 2020	Dec. 31, 2019	Jun. 30, 2019	Dec. 31, 2018
Derivative [Line Items]
Derivative asset, fair value	$ 130		$ 130			$ 190
Derivative liability, fair value	(13)		(13)			(6)
Derivative assets, at fair value	(130)		(130)			(190)
Derivative Liability	(13)		(13)			(6)
U.S. Treasury securities	0		0			97
U.S. Treasury Securities - short	(8,372)		(8,372)			(9,543)
Total - (short)/long, net	(8,372)		(8,372)			(9,446)
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	403	$ (546)	(3,014)	$ (2,979)
TBA and Forward Settling Agency Securities [Member]
Derivative [Line Items]
Notional Amount Of Derivatives Not Designated As Hedging Instruments Additions During The Period	80,599	24,305	193,535	70,606
Notional Amount Of Derivatives Not Designated As Hedging Instruments Settlement Expiration During The Period				(75,791)
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	283	144	1,196	390
Interest Rate Swap [Member]
Derivative [Line Items]
Derivative Liability, Notional Amount	42,975		42,975			79,075
Derivative liability, fair value	0		0			(2)
Notional Amount Of Derivatives Not Designated As Hedging Instruments Additions During The Period	24,975	82,625	100,700	152,975
Notional Amount Of Derivatives Not Designated As Hedging Instruments Settlement Expiration During The Period	(24,075)	(75,800)	(136,800)	(122,825)
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	140	(482)	(3,034)	(2,097)
Interest Rate Swap [Member] \| Fair Value, Inputs, Level 2 [Member]
Derivative [Line Items]
Derivative asset, fair value	41		41			21
Interest Rate Swaption [Member]
Derivative [Line Items]
Derivative Liability, Notional Amount	6,900		6,900			8,850
Notional Amount Of Derivatives Not Designated As Hedging Instruments Additions During The Period	0	4,500	2,000	7,150
Notional Amount Of Derivatives Not Designated As Hedging Instruments Settlement Expiration During The Period	(2,450)	(250)	(3,950)	(2,000)
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	(1)	(19)	(149)	(71)
Interest Rate Swaption [Member] \| Fair Value, Inputs, Level 2 [Member]
Derivative [Line Items]
Derivative asset, fair value	5		5			126
Purchases Of TBAs And Forward Settling Agency Securities [Member]
Derivative [Line Items]
Derivative liability, fair value	(8)		(8)			(4)
Notional Amount Of Derivatives Not Designated As Hedging Instruments Settlement Expiration During The Period	(71,838)	(33,381)	(172,336)
US Treasury Securities [Member]
Derivative [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	(5)	(40)	(117)	(128)
US Treasury Securities [Member] \| Fair Value, Recurring [Member] \| Future [Member] \| Fair Value, Inputs, Level 1 [Member]
Derivative [Line Items]
Derivative assets, at fair value	0		0			14
Derivative Liability	(5)		(5)			0
TBA and Forward Settling Agency Securities [Member] \| Fair Value, Recurring [Member] \| Purchases Of TBAs And Forward Settling Agency Securities [Member] \| Fair Value, Inputs, Level 2 [Member]
Derivative [Line Items]
Derivative assets, at fair value	(84)		(84)			(29)
Short [Member] \| US Treasury Securities [Member]
Derivative [Line Items]
Notional Amount Of Derivatives Not Designated As Hedging Instruments Additions During The Period	2,735	98	12,967	7,404
Notional Amount Of Derivatives Not Designated As Hedging Instruments Settlement Expiration During The Period	2,255	2,710	14,464	(24,116)
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	(15)	(154)	(1,012)	(1,084)
Long [Member] \| US Treasury Securities [Member]
Derivative [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	1	5	102	11
Debt Securities, Trading, and Equity Securities, FV-NI	1	209	1	209	$ 1,132	$ 95	$ 1,134	$ 45
Trading Securities Added During the Period	0	353	7,011	1,776
Notional Amount Of Trading Securities Settlement Expiration During The Period	$ (1,133)	$ (1,278)	$ (7,107)	$ (1,612)

Investment Securities (Summary Of Agency Securities Estimated Weighted Average Life Classifications) (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Agency securities classified as available for sale, Fair value	$ 68,044	$ 100,442
Agency securities classified as available for sale, Amortized cost	$ 65,024	$ 98,670
Weighted Average Coupon	3.59%	3.68%
Weighted Average Yield	2.56%	3.07%
Less Than or Equal to Three Years [Member]
Fair Value	$ 2,420	$ 2,671
Amortized Cost	$ 2,387	$ 2,654
Weighted Average Coupon	3.65%	3.54%
Weighted Average Yield	2.01%	2.61%
Greater Than Three Years and Less Than or Equal to Five Years [Member]
Fair Value	$ 37,564	$ 10,822
Amortized Cost	$ 35,873	$ 10,563
Weighted Average Coupon	3.76%	3.85%
Weighted Average Yield	2.62%	3.20%
Greater Than Five Years [Member]
Fair Value	$ 27,961	$ 86,492
Amortized Cost	$ 26,665	$ 85,002
Weighted Average Coupon	3.35%	3.67%
Weighted Average Yield	2.51%	3.07%
Greater Than Ten Years [Member]
Fair Value	$ 99	$ 457
Amortized Cost	$ 99	$ 451
Weighted Average Coupon	4.08%	3.31%
Weighted Average Yield	3.71%	3.06%

Derivative and Other Hedging Instruments (Remaining Interest Rate Swap Term) (Details) $ in Millions	3 Months Ended		6 Months Ended	9 Months Ended
	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2020 USD ($) month	Sep. 30, 2020 USD ($) month	Sep. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)
Interest Rate Swaps Linked to 3-Month LIBOR	0.00%			0.00%		11.00%
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	$ 403	$ (546)		$ (3,014)	$ (2,979)
Interest Rate Swaps Linked to Overnight Index Swap Rate	31.00%			31.00%		86.00%
Interest Rate Swaption [Member]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	$ (1)	(19)		$ (149)	(71)
Cost			$ 176	141
Fair Value	5			$ 5		$ 126
Average Months to Expiration \| month			11	7
Derivative Liability, Notional Amount	$ 6,900			$ 6,900		$ 8,850
Average Fixed Pay Rate	2.32%			2.32%		2.34%
Average Maturity (Years)			9 years 6 months	9 years 3 months 18 days
Interest Rate Swap [Member]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	$ 140	$ (482)		$ (3,034)	$ (2,097)
Derivative Liability, Notional Amount	$ 42,975			$ 42,975		$ 79,075
Average Fixed Pay Rate	0.15%			0.15%		1.29%
Average Maturity (Years)			2 years 8 months 12 days	5 years 3 months 18 days
Less Than or Equal to One Year [Member] \| Interest Rate Swaption [Member]
Cost			$ 123	$ 133
Fair Value	$ 3			$ 3		$ 80
Average Months to Expiration \| month			8	6
Derivative Liability, Notional Amount	$ 6,400			$ 6,400		$ 5,650
Average Fixed Pay Rate	2.35%			2.35%		2.26%
Average Maturity (Years)			9 years 3 months 18 days	9 years 2 months 12 days
Greater Than One Year and Less Than or Equal to Three Years [Member] \| Interest Rate Swap [Member]
Derivative Liability, Notional Amount	$ 8,750			$ 8,750		$ 59,700
Average Fixed Pay Rate	0.04%			0.04%		1.30%
Average Maturity (Years)			1 year 7 months 6 days	2 years 7 months 6 days
Bermudan [Member] \| Interest Rate Swaption [Member]
Derivative Liability, Notional Amount	$ 700			$ 700

Pledged Assets (Assets Pledged from Counterparties) (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Offsetting Assets and Liabilities [Line Items]
Restricted Cash and Cash Equivalents	$ 1,557	$ 451
Assets Pledged to Us [Member]
Offsetting Assets and Liabilities [Line Items]
Restricted Cash and Cash Equivalents	9	116
Restricted Cash and Securities Pledged	8,799	10,216
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] \| Assets Pledged to Us [Member]
Offsetting Assets and Liabilities [Line Items]
Pledged Financial Instruments, Not Separately Reported, Mortgage-Related Securities Available-for-sale or Held-for-investment	(211)	(1)
Restricted Cash and Cash Equivalents	4
Securities Sold under Agreements to Repurchase [Member] \| Assets Pledged to Us [Member]
Offsetting Assets and Liabilities [Line Items]
Pledged Financial Instruments, Not Separately Reported, Mortgage-Related Securities Available-for-sale or Held-for-investment	(215)	(1)
Derivative [Member] \| Assets Pledged to Us [Member]
Offsetting Assets and Liabilities [Line Items]
Restricted Cash and Securities Pledged	5	116
US Treasury Securities [Member] \| Assets Pledged to Us [Member]
Offsetting Assets and Liabilities [Line Items]
Pledged Financial Instruments, Not Separately Reported, Mortgage-Related Securities Available-for-sale or Held-for-investment	(8,790)	(10,100)
Reverse Repurchase Agreements [Member] \| Assets Pledged to Us [Member]
Offsetting Assets and Liabilities [Line Items]
Pledged Financial Instruments, Not Separately Reported, Mortgage-Related Securities Available-for-sale or Held-for-investment	(8,579)	(10,099)
Reverse Repurchase Agreements [Member] \| US Treasury Securities [Member] \| Assets Pledged to Us [Member]
Offsetting Assets and Liabilities [Line Items]
Pledged Financial Instruments, Not Separately Reported, Mortgage-Related Securities Available-for-sale or Held-for-investment	(8,579)	(10,099)
Derivative [Member]
Offsetting Assets and Liabilities [Line Items]
Restricted Cash and Cash Equivalents	909	340
Derivative [Member] \| US Treasury Securities [Member] \| Assets Pledged to Us [Member]
Offsetting Assets and Liabilities [Line Items]
Pledged Financial Instruments, Not Separately Reported, Mortgage-Related Securities Available-for-sale or Held-for-investment	0	0
Derivative [Member] \| Assets Pledged to Us [Member]
Offsetting Assets and Liabilities [Line Items]
Restricted Cash and Cash Equivalents	$ 5	$ 116

Investment Securities

9 Months Ended

Sep. 30, 2020

Investments, Debt and Equity Securities [Abstract]

Investment Securities

As of September 30, 2020 and December 31, 2019, our investment portfolio consisted of $68.0 billion and $100.4 billion of investment securities, at fair value, respectively, and $29.5 billion and $7.4 billion of net TBA securities, at fair value, respectively. Our net TBA position is reported at its net carrying value of $76 million and $25 million as of September 30, 2020 and December 31, 2019, respectively, in derivative assets / (liabilities) on our accompanying consolidated balance sheets. The net carrying value of our TBA position represents the difference between the fair value of the underlying Agency security in the TBA contract and the cost basis or the forward price to be paid or received for the underlying Agency security.

As of September 30, 2020 and December 31, 2019, our investment securities had a net unamortized premium balance of $2.6 billion and $3.1 billion, respectively.


	September 30, 2020				December 31, 2019
Investment Securities	Amortized Cost		Fair Value		Amortized Cost		Fair Value
Agency RMBS:
Fixed rate	$	63,307	$	66,278	$	96,375	$	98,074
Adjustable rate	96		99		160		163
CMO	327		341		441		447
Interest-only and principal-only strips	117		142		146		164
Multifamily	17		19		37		39
Total Agency RMBS	63,864		66,879		97,159		98,887
Non-Agency RMBS	172		177		198		209
CMBS	310		335		352		370
CRT securities	678		653		961		976
Total investment securities	$	65,024	$	68,044	$	98,670	$	100,442


	September 30, 2020
	Agency RMBS									Non-Agency
Investment Securities	Fannie Mae			Freddie Mac			Ginnie Mae			RMBS			CMBS			CRT			Total
Available-for-sale securities:
Par value	$	10,703		$	4,046		$	14		$	—		$	—		$	—		$	14,763
Unamortized discount	(6)			(1)			—			—			—			—			(7)
Unamortized premium	479			204			—			—			—			—			683
Amortized cost	11,176			4,249			14			—			—			—			15,439
Gross unrealized gains	618			215			1			—			—			—			834
Gross unrealized losses	—			—			—			—			—			—			—
Total available-for-sale securities, at fair value	11,794			4,464			15			—			—			—			16,273
Securities remeasured at fair value through earnings:
Par value	31,624			14,891			3			181			309			678			47,686
Unamortized discount	(20)			(1)			—			(11)			(4)			(12)			(48)
Unamortized premium	1,285			641			—			3			6			12			1,947
Amortized cost	32,889			15,531			3			173			311			678			49,585
Gross unrealized gains	1,411			782			—			8			28			3			2,232
Gross unrealized losses	(7)			(3)			—			(4)			(4)			(28)			(46)
Total securities remeasured at fair value through earnings	34,293			16,310			3			177			335			653			51,771
Total securities, at fair value	$	46,087		$	20,774		$	18		$	177		$	335		$	653		$	68,044
Weighted average coupon as of September 30, 2020	3.49		%	3.79		%	3.58		%	4.20		%	4.13		%	3.31		%	3.59		%
Weighted average yield as of September 30, 2020 1	2.49		%	2.66		%	2.22		%	0.53		%	4.40		%	3.47		%	2.56		%

________________________________

1.Incorporates a weighted average future constant prepayment rate assumption of 15.9% based on forward rates as of September 30, 2020.


	December 31, 2019
	Agency RMBS									Non-Agency
Investment Securities	Fannie Mae			Freddie Mac			Ginnie Mae			RMBS			CMBS			CRT			Total
Available-for-sale securities:
Par value	$	14,301		$	4,762		$	18		$	—		$	—		$	—		$	19,081
Unamortized discount	(10)			(2)			—			—			—			—			(12)
Unamortized premium	711			276			—			—			—			—			987
Amortized cost	15,002			5,036			18			—			—			—			20,056
Gross unrealized gains	142			29			1			—			—			—			172
Gross unrealized losses	(50)			(25)			—			—			—			—			(75)
Total available-for-sale securities, at fair value	15,094			5,040			19			—			—			—			20,153
Securities remeasured at fair value through earnings:
Par value	45,106			29,881			—			208			348			937			76,480
Unamortized discount	(68)			(2)			—			(10)			(3)			(2)			(85)
Unamortized premium	1,218			967			—			1			7			26			2,219
Amortized cost	46,256			30,846			—			199			352			961			78,614
Gross unrealized gains	991			691			—			10			19			18			1,729
Gross unrealized losses	(32)			(18)			—			—			(1)			(3)			(54)
Total securities remeasured at fair value through earnings	47,215			31,519			—			209			370			976			80,289
Total securities, at fair value	$	62,309		$	36,559		$	19		$	209		$	370		$	976		$	100,442
Weighted average coupon as of December 31, 2019	3.62		%	3.75		%	3.77		%	4.05		%	4.49		%	5.07		%	3.68		%
Weighted average yield as of December 31, 2019 1	3.03		%	3.09		%	2.08		%	4.39		%	4.38		%	4.05		%	3.07		%

________________________________

1.Incorporates a weighted average future constant prepayment rate assumption of 10.8% based on forward rates as of December 31, 2019.

As of September 30, 2020 and December 31, 2019, our investments in CRT and non-Agency securities had the following credit ratings:


	September 30, 2020						December 31, 2019
CRT and Non-Agency Security Credit Ratings 1	CRT		RMBS		CMBS		CRT		RMBS		CMBS
AAA	$	—	$	—	$	39	$	—	$	—	$	43
AA	—		20		181		—		81		214
A	—		33		22		13		25		34
BBB	42		82		55		67		71		69
BB	204		27		34		471		21		10
B	252		5		4		308		4		—
Not Rated	155		10		—		117		7		—
Total	$	653	$	177	$	335	$	976	$	209	$	370

________________________________

Our CRT securities reference the performance of loans underlying Agency RMBS issued by Fannie Mae or Freddie Mac, which were subject to their underwriting standards.

The actual maturities of our investment securities are generally shorter than their stated contractual maturities. The actual maturities of our Agency and high credit quality non-Agency RMBS are primarily affected by principal prepayments and to a lesser degree the contractual lives of the underlying mortgages and periodic contractual principal repayments. The actual maturities of our credit-oriented investments are primarily impacted by their contractual lives and default and loss recovery rates. As of September 30, 2020 and December 31, 2019, the weighted average expected constant prepayment rate ("CPR") over the remaining life of our Agency and high credit quality non-Agency RMBS investment portfolio was 15.9% and 10.8%, respectively. Our estimates can differ materially for different securities and thus our individual holdings have a wide range of projected CPRs. The following table summarizes our investments as of September 30, 2020 and December 31, 2019 according to their estimated weighted average life classification (dollars in millions):


	September 30, 2020						December 31, 2019
Estimated Weighted Average Life of Investment Securities	Fair Value		Amortized Cost		Weighted Average Coupon	Weighted Average Yield	Fair Value		Amortized Cost		Weighted Average Coupon	Weighted Average Yield
≤ 3 years	$	2,420	$	2,387	3.65%	2.01%	$	2,671	$	2,654	3.54%	2.61%
> 3 years and ≤ 5 years	37,564		35,873		3.76%	2.62%	10,822		10,563		3.85%	3.20%
> 5 years and ≤10 years	27,961		26,665		3.35%	2.51%	86,492		85,002		3.67%	3.07%
> 10 years	99		99		4.08%	3.71%	457		451		3.31%	3.06%
Total	$	68,044	$	65,024	3.59%	2.56%	$	100,442	$	98,670	3.68%	3.07%


	Unrealized Loss Position For
	Less than 12 Months				12 Months or More				Total
Securities Classified as Available-for-Sale	Fair Value		Unrealized Loss		Fair Value		Unrealized Loss		Fair Value		Unrealized Loss
September 30, 2020	$	13	$	—	$	—	$	—	$	13	$	—
December 31, 2019	$	1,653	$	(12)	$	6,984	$	(63)	$	8,637	$	(75)

Gains and Losses on Sale of Investment Securities


	Three Months Ended June 30,
	2020						2019
Investment Securities	Available-for-Sale Securities 2		Fair Value Option Securities		Total		Available-for-Sale Securities 2		Fair Value Option Securities		Total
Investment securities sold, at cost	$	—	$	(13,430)	$	(13,430)	$	—	$	(5,048)	$	(5,048)
Proceeds from investment securities sold 1	—		13,776		13,776		—		5,137		5,137
Net gain (loss) on sale of investment securities	$	—	$	346	$	346	$	—	$	89	$	89

Gross gain on sale of investment securities	$	—	$	354	$	354	$	—	$	90	$	90
Gross loss on sale of investment securities	—		(8)		(8)		—		(1)		(1)
Net gain (loss) on sale of investment securities	$	—	$	346	$	346	$	—	$	89	$	89


	Nine Months Ended September 30,
	2020						2019
Investment Securities	Available-for-Sale Securities 2		Fair Value Option Securities		Total		Available-for-Sale Securities 2		Fair Value Option Securities		Total
Investment securities sold, at cost	$	(1,433)	$	(67,342)	$	(68,775)	$	(705)	$	(17,379)	$	(18,084)
Proceeds from investment securities sold 1	1,473		68,295		69,768		696		17,669		18,365
Net gain (loss) on sale of investment securities	$	40	$	953	$	993	$	(9)	$	290	$	281

Gross gain on sale of investment securities	$	40	$	1,050	$	1,090	$	—	$	294	$	294
Gross loss on sale of investment securities	—		(97)		(97)		(9)		(4)		(13)
Net gain (loss) on sale of investment securities	$	40	$	953	$	993	$	(9)	$	290	$	281

________________________________

1.Proceeds include cash received during the period, plus receivable for investment securities sold during the period as of period end.

2.See Note 10 for a summary of changes in accumulated OCI.

Repurchase Agreements And Reverse Repurchase Agreements (Narrative) (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2020 USD ($) days	Dec. 31, 2019 USD ($) days
Assets Sold under Agreements to Repurchase [Line Items]
Receivable Under Reverse Repurchase Agreements	$ 8,625,000	$ 10,181,000
Securities Sold under Agreements to Repurchase	$ 54,566,000	$ 89,182,000
Short-term Debt, Weighted Average Interest Rate, at Point in Time	0.37%	2.17%
Debt of consolidated variable interest entities, at fair value	$ (192,000)	$ (228,000)
Repurchase Agreements Extinguished - Extinguishment of Debt	$ 3,700,000
Weighted Average Remaining Maturity of Repurchase Agreements Extinguished - Extinguished Debt	2 years 2 months 12 days
Gain (Loss) on Extinguishment of Debt	$ (146,000)
Weighted Average Interest Rate of Repurchase Agreements Extinguished - Extinguished Debt	2.11%
Short-term Debt, Weighted Average Interest Rate, over Time	2.11%
TBA securities Fifteen Year and Thirty Year Securities [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Derivative, Fair Value, Net	$ 76,000	25,000
TBA and Forward Settling Agency Securities [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Derivative, Forward Settlement Value	29,460,000	7,404,000
Derivative, Fair Value, Net	76,000	25,000
Maturity Overnight [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase	8,900,000	17,000,000
Forward Contracts [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Securities Sold under Agreements to Repurchase	$ 1,500,000	$ 4,500,000
Weighted Average Forward Start Days \| days	93	12
Short-term Debt, Weighted Average Interest Rate, at Point in Time	0.25%	1.60%
Bethesda Securities [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Percentage of Repurchase Agreement Funding	48.00%	40.00%
FICC [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Percentage of Repurchase Agreement Funding	48.00%	38.00%
Obligation to Return Securities Borrowed Under Reverse Repurchase Agreements at Fair Value	$ 3,600,000	$ 5,400,000

Investment Securities Investment Securities (Summary of Investment in Agency Security) (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Debt and Equity Securities, FV-NI [Line Items]
Debt Securities, Trading and Available-for-sale, Amortized Cost Basis	$ 65,024	$ 98,670
Debt Securities, Trading and Available-for-sale	68,044	100,442
Total agency MBS, at fair value	66,879	98,887
Mortgage-backed Securities, Issued by Private Enterprises [Member]
Debt and Equity Securities, FV-NI [Line Items]
Debt Securities, Trading and Available-for-sale, Amortized Cost Basis	172	198
Debt Securities, Trading and Available-for-sale	177	209
Commercial Mortgage Backed Securities [Member]
Debt and Equity Securities, FV-NI [Line Items]
Debt Securities, Trading and Available-for-sale, Amortized Cost Basis	310	352
Debt Securities, Trading and Available-for-sale	335	370
Credit Risk Transfer Securities [Member]
Debt and Equity Securities, FV-NI [Line Items]
Debt Securities, Trading and Available-for-sale, Amortized Cost Basis	678	961
Debt Securities, Trading and Available-for-sale	653	976
Fixed Income Securities [Member] \| Agency Securities [Member]
Debt and Equity Securities, FV-NI [Line Items]
Debt Securities, Trading and Available-for-sale, Amortized Cost Basis	63,307	96,375
Debt Securities, Trading and Available-for-sale	66,278	98,074
Adjustable-Rate [Member] \| Agency Securities [Member]
Debt and Equity Securities, FV-NI [Line Items]
Debt Securities, Trading and Available-for-sale, Amortized Cost Basis	96	160
Debt Securities, Trading and Available-for-sale	99	163
Collateralized Mortgage Obligations [Member] \| Agency Securities [Member]
Debt and Equity Securities, FV-NI [Line Items]
Debt Securities, Trading and Available-for-sale, Amortized Cost Basis	327	441
Debt Securities, Trading and Available-for-sale	341	447
Multifamily [Member] \| Agency Securities [Member]
Debt and Equity Securities, FV-NI [Line Items]
Debt Securities, Trading and Available-for-sale, Amortized Cost Basis	17	37
Debt Securities, Trading and Available-for-sale	19	39
Interest Only And Principal Only Strip [Member] \| Agency Securities [Member]
Debt and Equity Securities, FV-NI [Line Items]
Debt Securities, Trading and Available-for-sale, Amortized Cost Basis	117	146
Debt Securities, Trading and Available-for-sale	142	164
Agency Securities [Member]
Debt and Equity Securities, FV-NI [Line Items]
Debt Securities, Trading and Available-for-sale, Amortized Cost Basis	$ 63,864	$ 97,159

Derivative and Other Hedging Instruments

9 Months Ended

Sep. 30, 2020

Derivative Instruments and Hedging Activities Disclosure [Abstract]

US Government Futures Securities [Table Text Block]


U.S. Treasury Futures	September 30, 2020								December 31, 2019
Maturity	Notional Amount Long (Short)		Cost Basis		Fair Value		Net Carrying Value 1		Notional Amount Long (Short)		Cost Basis		Fair Value		Net Carrying Value 1
10 years	$	(1,000)	$	(1,390)	$	(1,395)	$	(5)	$	(1,000)	$	(1,298)	$	(1,284)	$	14

________________________________

Derivative and Other Hedging Instruments

We hedge a portion of our interest rate risk primarily utilizing interest rate swaps, interest rate swaptions, U.S. Treasury securities and U.S. Treasury futures contracts. We utilize TBA securities primarily as a means of investing in the Agency securities market. For additional information regarding our derivative instruments and our overall risk management strategy, please refer to the discussion of derivative and other hedging instruments in Note 3.

Derivative and Other Hedging Instrument Assets (Liabilities), at Fair Value

The table below summarizes fair value information about our derivative and other hedging instrument assets/(liabilities) as of September 30, 2020 and December 31, 2019 (in millions):


Derivative and Other Hedging Instruments	Balance Sheet Location	September 30, 2020		December 31, 2019
Interest rate swaps	Derivative assets, at fair value	$	41	$	21
Swaptions	Derivative assets, at fair value	5		126
TBA securities	Derivative assets, at fair value	84		29
U.S. Treasury futures - short	Derivative assets, at fair value	—		14
Total derivative assets, at fair value		$	130	$	190

Interest rate swaps	Derivative liabilities, at fair value	$	—	$	(2)
TBA securities	Derivative liabilities, at fair value	(8)		(4)
U.S. Treasury futures - short	Derivative liabilities, at fair value	(5)		—
Total derivative liabilities, at fair value		$	(13)	$	(6)

U.S. Treasury securities - long	U.S. Treasury securities, at fair value	$	—	$	97
U.S. Treasury securities - short	Obligation to return securities borrowed under reverse repurchase agreements, at fair value	(8,372)		(9,543)
Total U.S. Treasury securities, net at fair value		$	(8,372)	$	(9,446)

The following tables summarize certain characteristics of our derivative and other hedging instruments outstanding as of September 30, 2020 and December 31, 2019 (dollars in millions):


	September 30, 2020					December 31, 2019
Pay Fixed / Receive Variable Interest Rate Swaps	Notional Amount		Average Fixed Pay Rate	Average Receive Rate	Average Maturity (Years)	Notional Amount		Average Fixed Pay Rate	Average Receive Rate	Average Maturity (Years)
≤ 3 years	$	8,750	0.04%	0.08%	2.6	$	59,700	1.30%	1.58%	1.6
> 3 to ≤ 5 years	16,750		0.10%	0.08%	4.3	9,850		1.17%	1.55%	3.8
> 5 to ≤ 7 years	9,800		0.21%	0.08%	6.0	5,650		1.34%	1.70%	6.4
> 7 to ≤ 10 years	6,200		0.28%	0.08%	8.8	2,850		1.36%	1.58%	8.9
> 10 years	1,475		0.47%	0.08%	14.4	1,025		1.64%	1.78%	15.4
Total	$	42,975	0.15%	0.08%	5.3	$	79,075	1.29%	1.59%	2.7


Pay Fixed / Receive Variable Interest Rate Swaps by Receive Index (% of Notional Amount)	September 30, 2020		December 31, 2019
SOFR	69	%	3	%
OIS	31	%	86	%
3M LIBOR	—	%	11	%
Total	100	%	100	%


Swaptions	Option					Underlying Payer Swap
Current Option Expiration Date	Cost Basis		Fair Value		Average Months to Current Option Expiration Date 1	Notional Amount		Average Fixed Pay Rate 2	Average Term (Years)
September 30, 2020
≤ 1 year	$	133	$	3	6	$	6,400	2.35%	9.2
> 1 year ≤ 2 years	8		2		17	500		1.87%	10.0
Total	$	141	$	5	7	$	6,900	2.32%	9.3

December 31, 2019
≤ 1 year	$	123	$	80	8	$	5,650	2.26%	9.3
> 1 year ≤ 2 years	53		46		16	3,200		2.50%	10.0
Total	$	176	$	126	11	$	8,850	2.34%	9.5

________________________________


U.S. Treasury Securities	September 30, 2020						December 31, 2019
Maturity	Face Amount Long/(Short)		Cost Basis 1		Fair Value		Face Amount Long/(Short)		Cost Basis 1		Fair Value
5 years	$	(425)	$	(425)	$	(426)	$	95	$	95	$	97
7 years	(1,083)		(1,081)		(1,097)		—		—		—
10 years	(6,220)		(6,386)		(6,849)		(9,224)		(9,329)		(9,543)
Total U.S. Treasury securities	$	(7,728)	$	(7,892)	$	(8,372)	$	(9,129)	$	(9,234)	$	(9,446)

________________________________


U.S. Treasury Futures	September 30, 2020								December 31, 2019
Maturity	Notional Amount Long (Short)		Cost Basis		Fair Value		Net Carrying Value 1		Notional Amount Long (Short)		Cost Basis		Fair Value		Net Carrying Value 1
10 years	$	(1,000)	$	(1,390)	$	(1,395)	$	(5)	$	(1,000)	$	(1,298)	$	(1,284)	$	14

________________________________


	September 30, 2020								December 31, 2019
TBA Securities by Coupon	Notional Amount Long (Short)		Cost Basis		Fair Value		Net Carrying Value 1		Notional Amount Long (Short)		Cost Basis		Fair Value		Net Carrying Value 1
15-Year TBA securities:
≤ 2.0%	$	10,228	$	10,514	$	10,552	38		$	—	$	—	$	—	$	—
2.5%	866		907		904		(3)		805		811		812		1
3.0%	—		—		—		—		1,059		1,083		1,086		3
3.5%	—		—		—		—		241		250		250		—
4.0%	—		—		—		—		75		78		78		—
Total 15-Year TBA securities	11,094		11,421		11,456		35		2,180		2,222		2,226		4
30-Year TBA securities:
2.0%	11,375		11,694		11,736		42		—		—		—		—
2.5%	5,489		5,752		5,753		1		—		—		—		—
3.0%	395		415		413		(2)		5,008		5,052		5,073		21
3.5%	168		178		178		—		1,226		1,259		1,261		2
4.0%	—		—		—		—		(1,507)		(1,565)		(1,568)		(3)
≥ 4.5%	—		—		—		—		415		436		437		1
Total 30-Year TBA securities, net	17,427		18,039		18,080		41		5,142		5,182		5,203		21
Total TBA securities, net	$	28,521	$	29,460	$	29,536	$	76	$	7,322	$	7,404	$	7,429	$	25

________________________________

Gain (Loss) From Derivative Instruments and Other Securities, Net


Derivative and Other Hedging Instruments	Beginning Notional Amount		Additions	Settlement, Termination, Expiration or Exercise	Ending Notional Amount		Gain/(Loss) on Derivative Instruments and Other Securities, Net 1
Three months ended September 30, 2020:
TBA securities, net	$	19,760	80,599	(71,838)	$	28,521	$	283
Interest rate swaps - payer	$	42,075	24,975	(24,075)	$	42,975	140
Payer swaptions	$	9,350	—	(2,450)	$	6,900	(1)
U.S. Treasury securities - short position	$	(7,247)	(2,735)	2,255	$	(7,727)	(15)
U.S. Treasury securities - long position	$	1,132	—	(1,133)	$	(1)	1
U.S. Treasury futures contracts - short position	$	(1,000)	(1,000)	1,000	$	(1,000)	(5)
							$	403
Three months ended September 30, 2019:
TBA securities, net	$	11,043	24,305	(33,381)	$	1,967	$	144
Interest rate swaps - payer	$	74,950	82,625	(75,800)	$	81,775	(482)
Interest rate swaps - receiver	$	—	(175)	175	$	—	—
Payer swaptions	$	4,400	4,500	(250)	$	8,650	(19)
U.S. Treasury securities - short position	$	(7,245)	(98)	2,710	$	(4,633)	(154)
U.S. Treasury securities - long position	$	1,134	353	(1,278)	$	209	5
U.S. Treasury futures contracts - short position	$	(1,650)	(1,000)	1,650	$	(1,000)	(40)
							$	(546)



Nine months ended September 30, 2020:
TBA securities, net	$	7,322	193,535	(172,336)	$	28,521	$	1,196
Interest rate swaps - payer	$	79,075	100,700	(136,800)	$	42,975	(3,034)
Payer swaptions	$	8,850	2,000	(3,950)	$	6,900	(149)
U.S. Treasury securities - short position	$	(9,224)	(12,967)	14,464	$	(7,727)	(1,012)
U.S. Treasury securities - long position	$	95	7,011	(7,107)	$	(1)	102
U.S. Treasury futures contracts - short position	$	(1,000)	(3,000)	3,000	$	(1,000)	(117)
							$	(3,014)
Nine months ended September 30, 2019:
TBA securities, net	$	7,152	70,606	(75,791)	$	1,967	$	390
Interest rate swaps - payer	$	51,625	152,975	(122,825)	$	81,775	(2,097)
Interest rate swaps - receiver	$	—	(175)	175	$	—	—
Payer swaptions	$	3,500	7,150	(2,000)	$	8,650	(71)
U.S. Treasury securities - short position	$	(21,345)	(7,404)	24,116	$	(4,633)	(1,084)
U.S. Treasury securities - long position	$	45	1,776	(1,612)	$	209	11
U.S. Treasury futures contracts - short position	$	(1,650)	(4,300)	4,950	$	(1,000)	(128)
							$	(2,979)

________________________________

Derivative and Other Hedging Instruments (US Treasury Securities) (Details) - USD ($) $ in Millions	Sep. 30, 2020	Jun. 30, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Dec. 31, 2018
Derivative [Line Items]
U.S. Treasury securities, net	$ (8,372)		$ (9,446)
Weighted Average Yield Percentage	2.56%		3.07%
7 Years Maturity [Member]
Derivative [Line Items]
U.S. Treasury securities, net	$ (1,083)		$ 0
At Par Value [Member]
Derivative [Line Items]
U.S. Treasury securities, net	(7,728)		(9,129)
TBA and Forward Settling Agency Securities [Member]
Derivative [Line Items]
Derivative, Notional Amount	(28,521)	$ (19,760)	(7,322)	$ (1,967)	$ (11,043)	$ (7,152)
Derivative, Forward Settlement Value	(29,460)		(7,404)
Derivative Asset, Fair Value, Gross Asset	(29,536)		(7,429)
Derivative, Fair Value, Net	76		25
5 Year Maturity [Member]
Derivative [Line Items]
U.S. Treasury securities, net	(425)		95
10 Year Maturity [Member]
Derivative [Line Items]
U.S. Treasury securities, net	(6,220)		(9,224)
10 Year Maturity [Member] \| US Treasury Securities [Member]
Derivative [Line Items]
Derivative, Fair Value, Net	(5)		14
Short [Member] \| US Treasury Securities [Member]
Derivative [Line Items]
Derivative, Notional Amount	(7,727)	$ (7,247)	(9,224)	$ (4,633)	$ (7,245)	$ (21,345)
Short [Member] \| 10 Year Maturity [Member] \| US Treasury Securities [Member]
Derivative [Line Items]
Derivative, Notional Amount	(1,000)		(1,000)
Derivative, Forward Settlement Value	(1,390)		(1,298)
Derivative Asset, Fair Value, Gross Asset	(1,395)		(1,284)
Fair Value Hedging [Member]
Derivative [Line Items]
U.S. Treasury securities, net	(8,372)		(9,446)
Fair Value Hedging [Member] \| 7 Years Maturity [Member]
Derivative [Line Items]
U.S. Treasury securities, net	(1,097)		0
Fair Value Hedging [Member] \| 5 Year Maturity [Member]
Derivative [Line Items]
U.S. Treasury securities, net	(426)		97
Fair Value Hedging [Member] \| 10 Year Maturity [Member]
Derivative [Line Items]
U.S. Treasury securities, net	(6,849)		(9,543)
At Cost Basis [Member]
Derivative [Line Items]
U.S. Treasury securities, net	(7,892)		(9,234)
At Cost Basis [Member] \| 7 Years Maturity [Member]
Derivative [Line Items]
U.S. Treasury securities, net	(1,081)		0
At Cost Basis [Member] \| 5 Year Maturity [Member]
Derivative [Line Items]
U.S. Treasury securities, net	(425)		95
At Cost Basis [Member] \| 10 Year Maturity [Member]
Derivative [Line Items]
U.S. Treasury securities, net	$ (6,386)		$ (9,329)
US Treasury Securities [Member] \| Short [Member]
Derivative [Line Items]
Weighted Average Yield Percentage	1.32%		2.19%
US Treasury Securities [Member] \| Long [Member]
Derivative [Line Items]
Weighted Average Yield Percentage			2.21%