Pledged Assets (Narrative) (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Pledged Assets [Abstract]
Retained Interests in Consolidated VIE's Pledged as Collateral Under Repurchase Agreements	$ 49	$ 81
Risk Of Repurchase Agreement To Stockholders Equity	4.00%

Retained Interests in Consolidated VIE's Pledged as Collateral Under Repurchase Agreements

No definition available.

Name:	agnc_RetainedInterestsinConsolidatedVIEsPledgedasCollateralUnderRepurchaseAgreements
Namespace Prefix:	agnc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant