Finance Receivables and Allowance for Credit Losses Allowance for credit losses (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023	Dec. 31, 2022
Allowance for Credit Losses [Line Items]
Financing Receivable, Allowance for Credit Loss	$ 880	$ 873	$ 880	$ 873	$ 880	$ 882	$ 870	$ 845
Finance receivables, net	117,346		117,346			112,823
Financing Receivable, Allowance for Credit Loss, Writeoff	(131)	(78)	(260)	(174)
Financing Receivable, Allowance for Credit Loss, Recovery	42	38	84	77
Financing Receivable, Credit Loss, Expense (Reversal)	95	40	183	117
Financing Receivable, Allowance for Credit Losses, Other	(6)	3	(9)	8
Financing Receivable, before Allowance for Credit Loss	$ 118,226		118,226			113,705
Financing Receivable, Allowance for Credit Loss, Period Increase (Decrease)			$ (2)
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	$ 4	7	$ 4	7	3	3	7	7
Financing Receivable, Allowance for Credit Loss, Writeoff	(7)	0	(7)	0
Financing Receivable, Allowance for Credit Loss, Recovery	0	0	3	1
Financing Receivable, Credit Loss, Expense (Reversal)	8	0	5	(1)
Financing Receivable, Allowance for Credit Losses, Other	0	0	0	0
Financing Receivable, before Allowance for Credit Loss	36,911		36,911			35,313
Consumer Portfolio Segment [Member]
Allowance for Credit Losses [Line Items]
Financing Receivable, Allowance for Credit Loss	876	866	876	866	$ 877	879	$ 863	$ 838
Financing Receivable, Allowance for Credit Loss, Writeoff	(124)	(78)	(253)	(174)
Financing Receivable, Allowance for Credit Loss, Recovery	42	38	81	76
Financing Receivable, Credit Loss, Expense (Reversal)	87	40	178	118
Financing Receivable, Allowance for Credit Losses, Other	(6)	$ 3	(9)	$ 8
Financing Receivable, before Allowance for Credit Loss	81,315		81,315			78,392
Retail Installment loans, dealer financing, and other financing [Member]
Allowance for Credit Losses [Line Items]
Finance receivables, net	$ 109,689		$ 109,689			$ 105,476