Consolidations and Transfers of Financial Assets - Transfers of Financial Assets (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Transfers of Financial Assets [Line Items]
Portfolio securitizations: unpaid principal balance	$ 77,000	$ 197,100	$ 179,800	$ 413,900
Unconsolidated VIEs
Transfers of Financial Assets [Line Items]
Retained interests: principal and interest received	108	$ 144	222	$ 287
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	$ 1,700		$ 1,700		$ 2,000