Securitizations and Financings - Securitization Trusts (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Variable Interest Entities and Securitizations [Abstract]
Total collateral balances - UPB	$ 1,326	$ 1,503
Total certificate balances	1,329	1,512
Unconsolidated securitization trusts	$ 154	$ 193

Amount of financing receivable past due.

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant