Finance Receivables and Allowance for Credit Losses Allowance for credit losses (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Jun. 30, 2023	Dec. 31, 2022	Jun. 30, 2022	Dec. 31, 2021
Allowance for Credit Losses [Line Items]
Financing Receivable, Allowance for Credit Loss	$ 876	$ 760	$ 876	$ 760	$ 873	$ 845	$ 763	$ 925
Finance receivables, net	105,969		105,969			100,513
Financing Receivable, Allowance for Credit Loss, Writeoff	(105)	(73)	(279)	(197)
Financing Receivable, Allowance for Credit Loss, Recovery	37	40	114	129
Financing Receivable, Credit Loss, Expense (Reversal)	74	39	191	(81)
Financing Receivable, Allowance for Credit Losses, Other	(3)	(9)	5	(16)
Financing Receivable, before Allowance for Credit Loss	106,845		106,845			101,358
Financing Receivable, Allowance for Credit Loss, Period Increase (Decrease)	$ 3		$ 31
Financing Receivable, Threshold Period Past Due, Writeoff	120 days		120 days
Commercial Portfolio Segment [Member]
Allowance for Credit Losses [Line Items]
Financing Receivable, Allowance for Credit Loss	$ 6	9	$ 6	9	7	7	9	22
Financing Receivable, Allowance for Credit Loss, Writeoff	0	0	0	(1)
Financing Receivable, Allowance for Credit Loss, Recovery	0	1	1	3
Financing Receivable, Credit Loss, Expense (Reversal)	(1)	(1)	(2)	(14)
Financing Receivable, Allowance for Credit Losses, Other	0	0	0	(1)
Financing Receivable, before Allowance for Credit Loss	31,233		31,233			29,855
Consumer Portfolio Segment [Member]
Allowance for Credit Losses [Line Items]
Financing Receivable, Allowance for Credit Loss	870	751	870	751	$ 866	838	$ 754	$ 903
Financing Receivable, Allowance for Credit Loss, Writeoff	(105)	(73)	(279)	(196)
Financing Receivable, Allowance for Credit Loss, Recovery	37	39	113	126
Financing Receivable, Credit Loss, Expense (Reversal)	75	40	193	(67)
Financing Receivable, Allowance for Credit Losses, Other	(3)	$ (9)	5	$ (15)
Financing Receivable, before Allowance for Credit Loss	75,612		75,612			71,503
Retail Installment loans, dealer financing, and other financing [Member]
Allowance for Credit Losses [Line Items]
Finance receivables, net	$ 99,041		$ 99,041			$ 94,090