Finance Receivables and Allowance for Credit Losses Allowance for credit losses (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024	Dec. 31, 2024	Dec. 31, 2023
Allowance for Credit Losses [Line Items]
Financing Receivable, Allowance for Credit Loss	$ 881	$ 880	$ 864	$ 882
Finance receivables, net	119,171		121,950
Financing Receivable, Allowance for Credit Loss, Writeoff	(167)	(129)
Financing Receivable, Allowance for Credit Loss, Recovery	40	42
Financing Receivable, Credit Loss, Expense (Reversal)	140	88
Financing Receivable, Allowance for Credit Losses, Other	4	(3)
Financing Receivable, before Allowance for Credit Loss	120,052		122,814
Financing Receivable, Allowance for Credit Loss, Period Increase (Decrease)	$ 17
Financing Receivable, Threshold Period Past Due, Writeoff	120 days
Commercial Portfolio Segment [Member]
Allowance for Credit Losses [Line Items]
Financing Receivable, Allowance for Credit Loss	$ 9	3	4	3
Financing Receivable, Allowance for Credit Loss, Writeoff	(1)	0
Financing Receivable, Allowance for Credit Loss, Recovery	0	3
Financing Receivable, Credit Loss, Expense (Reversal)	5	(3)
Financing Receivable, Allowance for Credit Losses, Other	1	0
Financing Receivable, before Allowance for Credit Loss	37,406		39,482
Consumer Portfolio Segment [Member]
Allowance for Credit Losses [Line Items]
Financing Receivable, Allowance for Credit Loss	872	877	860	$ 879
Financing Receivable, Allowance for Credit Loss, Writeoff	(166)	(129)
Financing Receivable, Allowance for Credit Loss, Recovery	40	39
Financing Receivable, Credit Loss, Expense (Reversal)	135	91
Financing Receivable, Allowance for Credit Losses, Other	3	$ (3)
Financing Receivable, before Allowance for Credit Loss	82,646		83,332
Retail Installment loans, dealer financing, and other financing [Member]
Allowance for Credit Losses [Line Items]
Finance receivables, net	$ 110,846		$ 114,069