Consolidations and Transfers of Financial Assets - Transfers of Financial Assets (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Transfers of Financial Assets [Line Items]
Portfolio securitizations: unpaid principal balance	$ 56,100	$ 140,100	$ 235,900	$ 554,000
Unconsolidated VIEs
Transfers of Financial Assets [Line Items]
Retained interests: principal and interest received	86	$ 139	308	$ 426
Unconsolidated VIEs | Single Class MBS, REMIC & Megas
Transfers of Financial Assets [Line Items]
Retained interests: unpaid principal balance	1,000		1,000		$ 1,100
Retained interests: fair value	$ 1,500		$ 1,500		$ 2,000