Derivative and Other Hedging Instruments (Effect Of Derivative Instruments Not Designated As Hedges On Comprehensive Income Statement) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024	Mar. 31, 2025	Dec. 31, 2024	Mar. 31, 2024	Dec. 31, 2023
Changes in Derivative and Other Hedge Portfolio [Roll Forward]
Amount Gain/(Loss) Recognized in Income on Derivatives	$ (369)	$ 390	$ (1,380)	$ 1,492
Interest Rate Swaption [Member]
Changes in Derivative and Other Hedge Portfolio [Roll Forward]
Notional Amount	(2,000)	0	(2,000)	0	$ (2,000)	$ (2,000)
Additions	0		(1,500)	0
Settlement, Expirations or Exercise	0		1,500	1,250
Amount Gain/(Loss) Recognized in Income on Derivatives	(9)		(28)	33
TBA and Forward Settling Agency Securities [Member]
Changes in Derivative and Other Hedge Portfolio [Roll Forward]
Notional Amount	(8,407)	(5,511)	(8,407)	(5,511)	(7,811)	(6,955)	$ (8,651)	$ (5,332)
Additions	(35,699)	(36,523)	(63,666)	(61,913)
Settlement, Expirations or Exercise				61,734
Amount Gain/(Loss) Recognized in Income on Derivatives	11	(29)	88	(87)
Purchases Of TBAs And Forward Settling Agency Securities [Member]
Changes in Derivative and Other Hedge Portfolio [Roll Forward]
Settlement, Expirations or Exercise	35,103	39,663	62,214
Interest Rate Swap [Member]
Changes in Derivative and Other Hedge Portfolio [Roll Forward]
Additions	(2,600)	(6,400)	(10,750)	(11,570)
Settlement, Expirations or Exercise	5,300	2,100	5,300	7,350
Notional Amount	(45,096)		(45,096)
Amount Gain/(Loss) Recognized in Income on Derivatives	(236)	179	(805)	837
US Treasury Securities [Member]
Changes in Derivative and Other Hedge Portfolio [Roll Forward]
Amount Gain/(Loss) Recognized in Income on Derivatives	4	89	(96)	275
Receiver Swaption [Member]
Changes in Derivative and Other Hedge Portfolio [Roll Forward]
Notional Amount	(150)	(150)	(150)	(150)	(150)	(150)	(150)	(150)
Additions	0	0	0	0
Settlement, Expirations or Exercise	0	0	0	0
Amount Gain/(Loss) Recognized in Income on Derivatives	0	0	0	0
Credit Default Swap, Buying Protection
Changes in Derivative and Other Hedge Portfolio [Roll Forward]
Additions		(96)		(96)
Settlement, Expirations or Exercise		96		96
Amount Gain/(Loss) Recognized in Income on Derivatives		0		(3)
SOFR Futures Contracts
Changes in Derivative and Other Hedge Portfolio [Roll Forward]
Notional Amount	(1,200)		(1,200)			(1,200)
Interest Rate Receive Swap
Changes in Derivative and Other Hedge Portfolio [Roll Forward]
Additions		0		0
Settlement, Expirations or Exercise		1,000		1,000
Amount Gain/(Loss) Recognized in Income on Derivatives		0		(9)
Not Designated as Hedging Instrument [Member] \| Interest Rate Swaption [Member]
Changes in Derivative and Other Hedge Portfolio [Roll Forward]
Notional Amount								(1,250)
Not Designated as Hedging Instrument [Member] \| Interest Rate Swap [Member]
Changes in Derivative and Other Hedge Portfolio [Roll Forward]
Notional Amount	(45,096)	(48,696)	(45,096)	(48,696)	(47,796)	(39,646)	(44,396)	(44,476)
Not Designated as Hedging Instrument [Member] \| Credit Default Swap, Buying Protection
Changes in Derivative and Other Hedge Portfolio [Roll Forward]
Notional Amount		(96)		(96)			(96)	(96)
Not Designated as Hedging Instrument [Member] \| Interest Rate Receive Swap
Changes in Derivative and Other Hedge Portfolio [Roll Forward]
Notional Amount		0		0			(1,000)	(1,000)
Short [Member] \| US Treasury Securities [Member]
Changes in Derivative and Other Hedge Portfolio [Roll Forward]
Notional Amount	(21,396)	(13,999)	(21,396)	(13,999)	(17,636)	(17,792)	(12,807)	(11,347)
Additions	(7,971)	(3,163)	(11,792)	(6,264)
Settlement, Expirations or Exercise	4,211	1,971	8,188	3,612
Amount Gain/(Loss) Recognized in Income on Derivatives	(139)	163	(599)	501
Long [Member] \| US Treasury Securities [Member]
Changes in Derivative and Other Hedge Portfolio [Roll Forward]
Amount Gain/(Loss) Recognized in Income on Derivatives	0	(12)	60	(55)
Debt Securities, Trading, and Equity Securities, FV-NI	3,545	2,427	3,545	2,427	3,216	1,585	1,815	1,492
Trading Securities Added During the Period	3,968	1,672	9,356	3,341
Notional Amount Of Trading Securities Settlement Expiration During The Period	(3,639)	(1,060)	(7,396)	(2,406)
Long [Member] \| SOFR Futures Contracts
Changes in Derivative and Other Hedge Portfolio [Roll Forward]
Amount Gain/(Loss) Recognized in Income on Derivatives	3	(3)	13	(13)
Future [Member] \| Short [Member] \| US Treasury Securities [Member]
Changes in Derivative and Other Hedge Portfolio [Roll Forward]
Notional Amount	(1,964)	(41)	(1,964)	(41)	$ (1,523)	$ (4,373)	$ (3,039)	$ (6,429)
Additions	(4,014)	(582)	5,455	(3,966)
Settlement, Expirations or Exercise	$ 3,573	$ 3,580	$ (7,864)	$ 10,354

AGNC Investment Corp. 10-Q