Consolidations and Transfers of Financial Assets - Transfers of Financial Assets and Portfolio Securitizations (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Transfers of Financial Assets [Line Items]
Portfolio securitizations: unpaid principal balance	$ 31,200	$ 28,300
Unconsolidated VIEs
Transfers of Financial Assets [Line Items]
Retained interests: principal and interest received	64	$ 78
Unconsolidated VIEs | Single Class MBS, REMIC & Megas
Transfers of Financial Assets [Line Items]
Retained interests: unpaid principal balance	797		$ 821
Retained interests: fair value	$ 1,200		$ 1,300