Transfers of Receivables - Assets and Liabilities of Securitizations (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020	Sep. 30, 2020
Securitization Transactions [Line Items]
Cash and cash equivalents	$ 12,963	$ 14,349
Finance Receivables and Net Investment In Operating Leases, After Allowance for Credit Losses	116,463		$ 131,481
Related Debt	118,956	137,677
Total assets	136,068	158,129	$ 153,574
Adjusted Pool Balance		2,300
Required pool balance	12,300	14,100
Consolidated Entities [Member] | Securitization Transactions [Member]
Securitization Transactions [Line Items]
Cash and cash equivalents	6,000	3,200
Finance Receivables and Net Investment in Operating Leases, Before Allowance for Credit Losses	58,400	72,900
Allowance for Credit Losses	400	500
Finance Receivables and Net Investment In Operating Leases, After Allowance for Credit Losses	58,000	72,400
Related Debt	45,100	54,600
Consolidated Entities [Member] | Securitization Transactions [Member] | Financing Receivable [Member]
Securitization Transactions [Line Items]
Cash and cash equivalents	5,500	2,600
Finance Receivables and Net Investment in Operating Leases, Before Allowance for Credit Losses	49,600	60,100
Allowance for Credit Losses	400	500
Finance Receivables and Net Investment In Operating Leases, After Allowance for Credit Losses	49,200	59,600
Related Debt	39,500	46,900
Consolidated Entities [Member] | Securitization Transactions [Member] | Retail [Member]
Securitization Transactions [Line Items]
Cash and cash equivalents	2,100	2,400
Finance Receivables and Net Investment in Operating Leases, Before Allowance for Credit Losses	37,300	43,700
Allowance for Credit Losses	400	500
Finance Receivables and Net Investment In Operating Leases, After Allowance for Credit Losses	36,900	43,200
Related Debt	29,700	36,000
Consolidated Entities [Member] | Securitization Transactions [Member] | Wholesale [Member]
Securitization Transactions [Line Items]
Cash and cash equivalents	3,400	200
Finance Receivables and Net Investment in Operating Leases, Before Allowance for Credit Losses	12,300	16,400
Allowance for Credit Losses	0	0
Finance Receivables and Net Investment In Operating Leases, After Allowance for Credit Losses	12,300	16,400
Related Debt	9,800	10,900
Consolidated Entities [Member] | Securitization Transactions [Member] | Net Investment in Operating Leases [Member]
Securitization Transactions [Line Items]
Cash and cash equivalents	500	600
Finance Receivables and Net Investment in Operating Leases, Before Allowance for Credit Losses	8,800	12,800
Allowance for Credit Losses	0	0
Finance Receivables and Net Investment In Operating Leases, After Allowance for Credit Losses	8,800	12,800
Related Debt	5,600	7,700
Variable Interest Entity, Primary Beneficiary [Member]
Securitization Transactions [Line Items]
Cash and cash equivalents	5,657	2,822
Related Debt	39,576	46,770
Variable Interest Entity, Primary Beneficiary [Member] | Securitization Transactions [Member]
Securitization Transactions [Line Items]
Cash and cash equivalents	5,700	2,800
Finance Receivables and Net Investment in Operating Leases, Before Allowance for Credit Losses	52,300	64,700
Allowance for Credit Losses	300	400
Finance Receivables and Net Investment In Operating Leases, After Allowance for Credit Losses	52,000	64,300
Related Debt	39,600	46,800
Variable Interest Entity, Primary Beneficiary [Member] | Securitization Transactions [Member] | Financing Receivable [Member]
Securitization Transactions [Line Items]
Cash and cash equivalents	5,200	2,200
Finance Receivables and Net Investment in Operating Leases, Before Allowance for Credit Losses	43,500	51,900
Allowance for Credit Losses	300	400
Finance Receivables and Net Investment In Operating Leases, After Allowance for Credit Losses	43,200	51,500
Related Debt	34,000	39,100
Variable Interest Entity, Primary Beneficiary [Member] | Securitization Transactions [Member] | Retail [Member]
Securitization Transactions [Line Items]
Cash and cash equivalents	1,800	2,000
Finance Receivables and Net Investment in Operating Leases, Before Allowance for Credit Losses	31,500	35,800
Allowance for Credit Losses	300	400
Finance Receivables and Net Investment In Operating Leases, After Allowance for Credit Losses	31,200	35,400
Related Debt	24,400	28,400
Variable Interest Entity, Primary Beneficiary [Member] | Securitization Transactions [Member] | Wholesale [Member]
Securitization Transactions [Line Items]
Cash and cash equivalents	3,400	200
Finance Receivables and Net Investment in Operating Leases, Before Allowance for Credit Losses	12,000	16,100
Allowance for Credit Losses	0	0
Finance Receivables and Net Investment In Operating Leases, After Allowance for Credit Losses	12,000	16,100
Related Debt	9,600	10,700
Variable Interest Entity, Primary Beneficiary [Member] | Securitization Transactions [Member] | Net Investment in Operating Leases [Member]
Securitization Transactions [Line Items]
Cash and cash equivalents	500	600
Finance Receivables and Net Investment in Operating Leases, Before Allowance for Credit Losses	8,800	12,800
Allowance for Credit Losses	0	0
Finance Receivables and Net Investment In Operating Leases, After Allowance for Credit Losses	8,800	12,800
Related Debt	5,600	7,700
Consolidated Entity Excluding Variable Interest Entities (VIE) [Member] | Securitization Transactions [Member]
Securitization Transactions [Line Items]
Cash and cash equivalents	300	400
Finance Receivables and Net Investment in Operating Leases, Before Allowance for Credit Losses	6,100	8,200
Allowance for Credit Losses	100	100
Finance Receivables and Net Investment In Operating Leases, After Allowance for Credit Losses	6,000	8,100
Related Debt	5,500	7,800
Consolidated Entity Excluding Variable Interest Entities (VIE) [Member] | Securitization Transactions [Member] | Financing Receivable [Member]
Securitization Transactions [Line Items]
Cash and cash equivalents	300	400
Finance Receivables and Net Investment in Operating Leases, Before Allowance for Credit Losses	6,100	8,200
Allowance for Credit Losses	100	100
Finance Receivables and Net Investment In Operating Leases, After Allowance for Credit Losses	6,000	8,100
Related Debt	5,500	7,800
Consolidated Entity Excluding Variable Interest Entities (VIE) [Member] | Securitization Transactions [Member] | Retail [Member]
Securitization Transactions [Line Items]
Cash and cash equivalents	300	400
Finance Receivables and Net Investment in Operating Leases, Before Allowance for Credit Losses	5,800	7,900
Allowance for Credit Losses	100	100
Finance Receivables and Net Investment In Operating Leases, After Allowance for Credit Losses	5,700	7,800
Related Debt	5,300	7,600
Consolidated Entity Excluding Variable Interest Entities (VIE) [Member] | Securitization Transactions [Member] | Wholesale [Member]
Securitization Transactions [Line Items]
Cash and cash equivalents	0	0
Finance Receivables and Net Investment in Operating Leases, Before Allowance for Credit Losses	300	300
Allowance for Credit Losses	0	0
Finance Receivables and Net Investment In Operating Leases, After Allowance for Credit Losses	300	300
Related Debt	200	200
Consolidated Entity Excluding Variable Interest Entities (VIE) [Member] | Securitization Transactions [Member] | Net Investment in Operating Leases [Member]
Securitization Transactions [Line Items]
Cash and cash equivalents	0	0
Finance Receivables and Net Investment in Operating Leases, Before Allowance for Credit Losses	0	0
Allowance for Credit Losses	0	0
Finance Receivables and Net Investment In Operating Leases, After Allowance for Credit Losses	0	0
Related Debt	$ 0	$ 0