Finance Receivables - Finance Receivables, net (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total finance receivables, net	$ 58,390	$ 53,473
Retail Finance Receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total finance receivables	51,288	42,268
Less: allowance for loan losses	(1,915)	(866)	$ (844)	$ (889)
Finance receivables, net	49,373	41,402
Commercial Finance Receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total finance receivables	9,080	12,149
Less: allowance for loan losses	(63)	(78)
Finance receivables, net	9,017	12,071
Dealer cash management balances	1,400	1,200
Fair Value, Inputs, Level 2 [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Fair value utilizing inputs	9,017	12,071
Fair Value, Inputs, Level 3 [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Fair value utilizing inputs	$ 51,645	$ 42,012