Condensed Consolidated Balance Sheet & Mini Balance Sheet - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Assets [Abstract]
Cash and cash equivalents, noninterest-bearing	$ 946	$ 810
Cash and cash equivalents, interest-bearing	3,011	3,727
Total cash and cash equivalents	3,957	4,537
Equity securities	536	773
Available-for-sale securities	27,630	25,303
Held-to-maturity securities	2,387	2,362
Loans held-for-sale, net	107	314
Finance receivables and loans, net [Abstract]
Finance receivables and loans, net of unearned income	130,055	129,926
Allowance for loan losses	1,288	1,242
Total finance receivables and loans, net	128,767	128,684
Investment in operating leases, net	8,339	8,417
Premiums receivable and other insurance assets	2,401	2,326
Other assets	5,993	6,153
Total assets	180,117	178,869
Liabilities and Equity [Abstract]
Deposit liabilities, noninterest-bearing	141	142
Deposit liabilities, interest-bearing	113,158	106,036
Total deposit liabilities	113,299	106,178
Short-term borrowings	6,115	9,987
Long-term debt	41,490	44,193
Interest payable	696	523
Unearned insurance premiums and service revenue	3,096	3,044
Accrued expenses and other liabilities	1,722	1,676
Total liabilities	166,418	165,601
Equity [Abstract]
Common stock and paid-in capital	21,379	21,345
Accumulated deficit	(5,195)	(5,489)
Accumulated other comprehensive loss	(225)	(539)
Treasury stock, at cost	(2,260)	(2,049)
Total equity	13,699	13,268
Total liabilities and equity	180,117	178,869
Variable interest entity
Finance receivables and loans, net [Abstract]
Finance receivables and loans, net of unearned income	16,772	18,086
Allowance for loan losses	99	114
Total finance receivables and loans, net	16,673	17,972
Investment in operating leases, net	123	164
Other assets	636	767
Total assets	17,432	18,903
Liabilities and Equity [Abstract]
Long-term debt	9,742	10,482
Accrued expenses and other liabilities	11	12
Total liabilities	$ 9,753	$ 10,494