Variable Interest Entities - Re-securitizations (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024
Transfers of securities to VIEs
U.S. GSEs and government agencies	$ 9,625,000,000	$ 12,353,000,000	$ 19,823,000,000	$ 33,531,000,000
Securities Transferred To Private Label Resecuritization VIEs	0	$ 0	0	$ 0
U.S. GSEs and government agencies | Nonconsolidated re-securitization VIEs
Variable Interest Entity [Line Items]
Interest in VIEs	$ 2,778,000,000		$ 2,778,000,000		$ 3,219,000,000