Other Assets and Other Liabilities and Deferred Income (Details) - USD ($)	Dec. 31, 2020	Jan. 01, 2020	Dec. 31, 2019
Other Assets [Abstract]
Accrued interest and other non-finance receivables	$ 1,726,000,000		$ 898,000,000
Collateral held for resale, at net realizable value, and other inventory	675,000,000		843,000,000
Prepaid reinsurance premiums and other reinsurance recoverables	708,000,000		687,000,000
Deferred charges - income taxes	165,000,000		171,000,000
Property and equipment, net of accumulated depreciation	219,000,000		212,000,000
Restricted cash	647,000,000		139,000,000
Investment in non-consolidated affiliates	132,000,000		132,000,000
Operating Lease, Right-of-Use Asset	98,000,000		108,000,000
Other	223,000,000		208,000,000
Total other assets	4,593,000,000	$ 3,390,000,000	3,398,000,000
Accumulated depreciation	365,000,000		393,000,000
Other Liabilities and Deferred Income [Abstract]
Unearned insurance premiums and fees	822,000,000		806,000,000
Interest payable	857,000,000		888,000,000
Taxes Payable	147,000,000		433,000,000
Deferred revenue	87,000,000		110,000,000
Other	293,000,000		286,000,000
Other liabilities and deferred income	2,306,000,000		2,633,000,000
Related Party Transactions Income Taxes and Related Interest Payable	$ 16,000,000		$ 294,000,000
Operating Lease, Liability, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilities		us-gaap:OtherLiabilities
Other Liabilities
Other Liabilities and Deferred Income [Abstract]
Operating Lease, Liability	$ 100,000,000		$ 110,000,000
Accounting Standards Update 2016-13 [Member]
Other Assets [Abstract]
Investment in non-consolidated affiliates	8,000,000
Total other assets		$ (8,000,000)
Parent [Member]
Other Liabilities and Deferred Income [Abstract]
Income Taxes Receivable	$ 867		$ 0