Consolidated Balance Sheet & Mini Balance Sheet - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Assets [Abstract]
Cash and cash equivalents, noninterest-bearing	$ 724	$ 619
Cash and cash equivalents, interest-bearing	14,897	2,936
Total cash and cash equivalents	15,621	3,555
Equity securities	1,071	616
Available-for-sale securities	29,830	30,284
Held-to-maturity securities, fair value	1,331	1,600
Held-to-maturity securities	1,253	1,568
Loans held-for-sale, net	406	158
Finance receivables and loans, net [Abstract]
Finance receivables and loans, net	118,534	128,231
Allowance for loan losses	3,283	1,263
Total finance receivables and loans, net	115,251	126,968
Investment in operating leases, net	9,639	8,864
Premiums receivable and other insurance assets	2,679	2,558
Other assets	6,415	6,073
Total assets	182,165	180,644
Liabilities and Equity [Abstract]
Deposit liabilities, noninterest-bearing	128	119
Deposit liabilities, interest-bearing	136,908	120,633
Total deposit liabilities	137,036	120,752
Short-term borrowings	2,136	5,531
Long-term debt	22,006	34,027
Interest payable	412	641
Unearned insurance premiums and service revenue	3,438	3,305
Accrued expenses and other liabilities	2,434	1,972
Total liabilities	$ 167,462	$ 166,228
Equity [Abstract]
Common stock, par value per share	$ 0.01	$ 0.01
Common stock, shares authorized	1,100,000,000	1,100,000,000
Total common stock shares issued	501,237,055	496,957,805
Common stock, shares outstanding	374,674,415	374,331,998
Common Stocks, Including Additional Paid in Capital	$ 21,544	$ 21,438
Accumulated deficit	(4,278)	(4,057)
Accumulated other comprehensive income (loss)	$ 631	$ 123
Treasury stock, shares	126,562,640	122,625,807
Treasury stock, at cost	$ (3,194)	$ (3,088)
Total equity	14,703	14,416
Total liabilities and equity	182,165	180,644
Available-for-sale debt securities | Available-for-sale securities
Assets [Abstract]
Debt securities, available-for-sale, amortized cost	28,936	29,967
Available-for-sale securities	29,830	30,284
On-balance sheet variable interest entities
Finance receivables and loans, net [Abstract]
Allowance for loan losses	285	153
Total finance receivables and loans, net	13,213	18,557
Other assets	983	787
Total assets	14,196	19,344
Liabilities and Equity [Abstract]
Long-term debt	4,158	9,087
Accrued expenses and other liabilities	3	11
Total liabilities	4,161	9,098
On-balance sheet variable interest entities | Consumer portfolio segment
Finance receivables and loans, net [Abstract]
Finance receivables and loans, net	7,630	10,791
On-balance sheet variable interest entities | Commercial portfolio segment
Finance receivables and loans, net [Abstract]
Finance receivables and loans, net	$ 5,868	$ 7,919