Finance Receivables - Schedule of Delinquency (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024
Gross charge-offs
2025			$ 75		$ 171
2024			447		556
2023			412		495
2022			277		305
2021			158		126
Prior			92		102
Total			1,461		1,754
Retail Finance Receivables
Financing Receivable, Past Due [Line Items]
2025	$ 24,333		24,333		31,101
2024	22,431		22,431		20,100
2023	13,900		13,900		12,802
2022	8,397		8,397		7,642
2021	4,704		4,704		3,575
Prior	2,093		2,093		847
Total	$ 75,857	$ 74,384	$ 75,857	$ 74,384	$ 76,066
Percent of portfolio	100.00%	100.00%	100.00%	100.00%	100.00%
Gross charge-offs
Total	$ 494	$ 439	$ 1,461	$ 1,255
Retail Finance Receivables | Performing Financial Instruments | 0 - 30 days
Financing Receivable, Past Due [Line Items]
2025	24,021		24,021		$ 30,581
2024	21,756		21,756		19,411
2023	13,324		13,324		12,207
2022	7,939		7,939		7,178
2021	4,378		4,378		3,350
Prior	1,900		1,900		710
Total	$ 73,318	$ 71,977	$ 73,318	$ 71,977	$ 73,438
Percent of portfolio	96.70%	96.80%	96.70%	96.80%	96.50%
Retail Finance Receivables | Nonperforming Financial Instruments | 31 - 60 days
Financing Receivable, Past Due [Line Items]
2025	$ 221		$ 221		$ 374
2024	466		466		481
2023	395		395		425
2022	324		324		340
2021	235		235		166
Prior	139		139		99
Total	$ 1,779	$ 1,718	$ 1,779	$ 1,718	$ 1,885
Percent of portfolio	2.30%	2.30%	2.30%	2.30%	2.50%
Retail Finance Receivables | Nonperforming Financial Instruments | Greater than 60 days
Financing Receivable, Past Due [Line Items]
2025	$ 79		$ 79		$ 128
2024	184		184		188
2023	160		160		155
2022	122		122		115
2021	85		85		55
Prior	52		52		36
Total	$ 682	$ 616	$ 682	$ 616	$ 677
Percent of portfolio	0.90%	0.80%	0.90%	0.80%	0.90%
Retail Finance Receivables | Nonperforming Financial Instruments | Finance receivables more than 30 days delinquent
Financing Receivable, Past Due [Line Items]
2025	$ 300		$ 300		$ 502
2024	649		649		669
2023	555		555		580
2022	446		446		455
2021	319		319		221
Prior	191		191		135
Total	$ 2,461	$ 2,333	$ 2,461	$ 2,333	$ 2,562
Percent of portfolio	3.20%	3.10%	3.20%	3.10%	3.40%
Retail Finance Receivables | Nonperforming Financial Instruments | In repossession
Financing Receivable, Past Due [Line Items]
2025	$ 11		$ 11		$ 17
2024	26		26		19
2023	20		20		14
2022	12		12		10
2021	6		6		3
Prior	2		2		2
Total	$ 78	$ 73	$ 78	$ 73	$ 66
Percent of portfolio	0.10%	0.10%	0.10%	0.10%	0.10%
Retail Finance Receivables | Nonperforming Financial Instruments | Finance receivables more than 30 days delinquent or in repossession
Financing Receivable, Past Due [Line Items]
2025	$ 312		$ 312		$ 519
2024	676		676		689
2023	575		575		595
2022	458		458		464
2021	325		325		225
Prior	194		194		136
Total	$ 2,540	$ 2,407	$ 2,540	$ 2,407	$ 2,628
Percent of portfolio	3.30%	3.20%	3.30%	3.20%	3.50%