Variable Interest Entities - Re-securitizations (Details) - USD ($)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Transfers of securities to VIEs
U.S. GSEs and government agencies	$ 8,406,000,000	$ 3,406,000,000
Securities Transferred To Private Label Resecuritization VIEs	0	$ 0
U.S. GSEs and government agencies | Nonconsolidated re-securitization VIEs
Variable Interest Entity [Line Items]
Interest in VIEs	$ 2,877,000,000		$ 3,371,000,000