Variable Interest Entities - Re-securitizations (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Transfers of securities to VIEs
U.S. GSEs and government agencies	$ 12,353,000,000	$ 4,521,000,000	$ 33,531,000,000	$ 14,188,000,000
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	$ 5,361,000,000		$ 5,361,000,000		$ 3,371,000,000