Finance Receivables - Finance Receivables, net (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables, net	$ 52,820	$ 53,473
Level 2 [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Fair value utilizing inputs	12,195	12,071
Level 3 [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Fair value utilizing inputs	41,963	42,012
Retail Finance Receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables, net of fees	42,504	42,268
Less: allowance for loan losses	(1,879)	(866)	$ (862)	$ (844)
Total finance receivables, net	40,625	41,402
Deferred income	125	83
Commercial Finance Receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance receivables, net of fees	12,282	12,149
Less: allowance for loan losses	(87)	(78)
Total finance receivables, net	12,195	12,071
Dealer cash management balances	$ 1,200	$ 1,200