Securitizations and Financings - Securitization Trusts (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Variable Interest Entities and Securitizations [Abstract]
Total collateral balances - UPB	$ 1,122	$ 1,326
Total certificate balances	1,112	1,329
Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Unconsolidated securitization trusts	$ 138	$ 154

Amount, before allowance for credit loss, of financing receivable.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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