Pledged Assets (Offsetting Assets and Liabilities) (Details) - USD ($) $ in Millions	Mar. 31, 2026	Dec. 31, 2025
Offsetting Assets and Liabilities [Line Items]
Collateral Received	$ (4,656)
Assets [Member]
Offsetting Assets and Liabilities [Line Items]
Gross Amounts of Recognized Assets	17,715	$ 16,773
Gross Amount Offset in the Consolidated Balance Sheets	0
Net Amounts of Assets Presented in the Consolidated Balance Sheets	17,715	16,773
Financial Instruments	(13,043)	(12,509)
Collateral Received		(4,207)
Net Amount	16	57
Assets [Member] \| ERROR in label resolution.
Offsetting Assets and Liabilities [Line Items]
Gross Amounts of Recognized Assets	18	81
Net Amounts of Assets Presented in the Consolidated Balance Sheets	18	81
Financial Instruments	0	0
Collateral Received	(18)	(24)
Net Amount	0	57
Assets [Member] \| TBA and Forward Settling Agency Securities [Member]
Offsetting Assets and Liabilities [Line Items]
Gross Amounts of Recognized Assets	53	77
Net Amounts of Assets Presented in the Consolidated Balance Sheets	53	77
Financial Instruments	(53)	(6)
Collateral Received	0	(71)
Net Amount	0	0
Assets [Member] \| Reverse Repurchase Agreements [Member]
Offsetting Assets and Liabilities [Line Items]
Net Amount	16	0
Liability [Member]
Offsetting Assets and Liabilities [Line Items]
Gross Amounts of Recognized Assets	87,863	85,292
Gross Amount Offset in the Consolidated Balance Sheets	0
Net Amounts of Assets Presented in the Consolidated Balance Sheets	87,863	85,292
Financial Instruments	(13,043)	(12,509)
Collateral Received	(74,820)	(72,783)
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]
Net Amount		0
Liability [Member] \| TBA and Forward Settling Agency Securities [Member]
Offsetting Assets and Liabilities [Line Items]
Gross Amounts of Recognized Assets	247	6
Net Amounts of Assets Presented in the Consolidated Balance Sheets	247	6
Financial Instruments	(53)	(6)
Collateral Received	(194)	0
Net Amount	0	0
Reverse Repurchase Agreements [Member] \| Assets [Member]
Offsetting Assets and Liabilities [Line Items]
Gross Amounts of Recognized Assets	17,644	16,615
Gross Amount Offset in the Consolidated Balance Sheets	0
Net Amounts of Assets Presented in the Consolidated Balance Sheets	17,644	16,615
Financial Instruments	(12,990)	(12,503)
Collateral Received	(4,638)	(4,112)
Repurchase Agreements [Member] \| Liability [Member]
Offsetting Assets and Liabilities [Line Items]
Gross Amounts of Recognized Assets	87,616	85,286
Gross Amount Offset in the Consolidated Balance Sheets	0
Net Amounts of Assets Presented in the Consolidated Balance Sheets	87,616	85,286
Financial Instruments	(12,990)	(12,503)
Collateral Received	$ (74,626)	$ (72,783)

AGNC Investment Corp. 10-Q