Transfers of Receivables - Assets and Liabilities of Securitizations (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019	Sep. 30, 2019
Securitization Transactions [Line Items]
Cash and cash equivalents	$ 11,078	$ 9,067
Finance Receivables and Net Investment In Operating Leases, After Allowance for Credit Losses	131,481		$ 140,301
Related Debt	133,073	140,029
Total assets	154,518	161,426	$ 160,883
Adjusted Pool Balance	3,900	8,700
Required pool balance	13,500	18,100
Consolidated Entities [Member] | Securitization Transactions [Member]
Securitization Transactions [Line Items]
Cash and cash equivalents	3,300	3,500
Finance Receivables and Net Investment in Operating Leases, Before Allowance for Credit Losses	73,100	80,000
Allowance for Credit Losses	500	200
Finance Receivables and Net Investment In Operating Leases, After Allowance for Credit Losses	72,600	79,800
Related Debt	53,200	56,600
Consolidated Entities [Member] | Securitization Transactions [Member] | Financing Receivable [Member]
Securitization Transactions [Line Items]
Cash and cash equivalents	2,500	3,000
Finance Receivables and Net Investment in Operating Leases, Before Allowance for Credit Losses	58,500	65,100
Allowance for Credit Losses	500	200
Finance Receivables and Net Investment In Operating Leases, After Allowance for Credit Losses	58,000	64,900
Related Debt	44,000	47,100
Consolidated Entities [Member] | Securitization Transactions [Member] | Retail [Member]
Securitization Transactions [Line Items]
Cash and cash equivalents	2,300	2,100
Finance Receivables and Net Investment in Operating Leases, Before Allowance for Credit Losses	41,100	38,300
Allowance for Credit Losses	500	200
Finance Receivables and Net Investment In Operating Leases, After Allowance for Credit Losses	40,600	38,100
Related Debt	33,500	33,100
Consolidated Entities [Member] | Securitization Transactions [Member] | Wholesale [Member]
Securitization Transactions [Line Items]
Cash and cash equivalents	200	900
Finance Receivables and Net Investment in Operating Leases, Before Allowance for Credit Losses	17,400	26,800
Allowance for Credit Losses	0	0
Finance Receivables and Net Investment In Operating Leases, After Allowance for Credit Losses	17,400	26,800
Related Debt	10,500	14,000
Consolidated Entities [Member] | Securitization Transactions [Member] | Net Investment in Operating Leases [Member]
Securitization Transactions [Line Items]
Cash and cash equivalents	800	500
Finance Receivables and Net Investment in Operating Leases, Before Allowance for Credit Losses	14,600	14,900
Allowance for Credit Losses	0	0
Finance Receivables and Net Investment In Operating Leases, After Allowance for Credit Losses	14,600	14,900
Related Debt	9,200	9,500
Variable Interest Entity, Primary Beneficiary [Member]
Securitization Transactions [Line Items]
Cash and cash equivalents	2,905	3,202
Related Debt	44,766	50,865
Variable Interest Entity, Primary Beneficiary [Member] | Securitization Transactions [Member]
Securitization Transactions [Line Items]
Cash and cash equivalents	2,900	3,200
Finance Receivables and Net Investment in Operating Leases, Before Allowance for Credit Losses	63,500	73,600
Allowance for Credit Losses	400	200
Finance Receivables and Net Investment In Operating Leases, After Allowance for Credit Losses	63,100	73,400
Related Debt	44,800	50,900
Variable Interest Entity, Primary Beneficiary [Member] | Securitization Transactions [Member] | Financing Receivable [Member]
Securitization Transactions [Line Items]
Cash and cash equivalents	2,100	2,700
Finance Receivables and Net Investment in Operating Leases, Before Allowance for Credit Losses	48,900	58,700
Allowance for Credit Losses	400	200
Finance Receivables and Net Investment In Operating Leases, After Allowance for Credit Losses	48,500	58,500
Related Debt	35,600	41,400
Variable Interest Entity, Primary Beneficiary [Member] | Securitization Transactions [Member] | Retail [Member]
Securitization Transactions [Line Items]
Cash and cash equivalents	1,900	1,800
Finance Receivables and Net Investment in Operating Leases, Before Allowance for Credit Losses	32,000	32,600
Allowance for Credit Losses	400	200
Finance Receivables and Net Investment In Operating Leases, After Allowance for Credit Losses	31,600	32,400
Related Debt	25,200	28,000
Variable Interest Entity, Primary Beneficiary [Member] | Securitization Transactions [Member] | Wholesale [Member]
Securitization Transactions [Line Items]
Cash and cash equivalents	200	900
Finance Receivables and Net Investment in Operating Leases, Before Allowance for Credit Losses	16,900	26,100
Allowance for Credit Losses	0	0
Finance Receivables and Net Investment In Operating Leases, After Allowance for Credit Losses	16,900	26,100
Related Debt	10,400	13,400
Variable Interest Entity, Primary Beneficiary [Member] | Securitization Transactions [Member] | Net Investment in Operating Leases [Member]
Securitization Transactions [Line Items]
Cash and cash equivalents	800	500
Finance Receivables and Net Investment in Operating Leases, Before Allowance for Credit Losses	14,600	14,900
Allowance for Credit Losses	0	0
Finance Receivables and Net Investment In Operating Leases, After Allowance for Credit Losses	14,600	14,900
Related Debt	9,200	9,500
Consolidated Entity Excluding Variable Interest Entities (VIE) [Member] | Securitization Transactions [Member]
Securitization Transactions [Line Items]
Cash and cash equivalents	400	300
Finance Receivables and Net Investment in Operating Leases, Before Allowance for Credit Losses	9,600	6,400
Allowance for Credit Losses	100	0
Finance Receivables and Net Investment In Operating Leases, After Allowance for Credit Losses	9,500	6,400
Related Debt	8,400	5,700
Consolidated Entity Excluding Variable Interest Entities (VIE) [Member] | Securitization Transactions [Member] | Financing Receivable [Member]
Securitization Transactions [Line Items]
Cash and cash equivalents	400	300
Finance Receivables and Net Investment in Operating Leases, Before Allowance for Credit Losses	9,600	6,400
Allowance for Credit Losses	100	0
Finance Receivables and Net Investment In Operating Leases, After Allowance for Credit Losses	9,500	6,400
Related Debt	8,400	5,700
Consolidated Entity Excluding Variable Interest Entities (VIE) [Member] | Securitization Transactions [Member] | Retail [Member]
Securitization Transactions [Line Items]
Cash and cash equivalents	400	300
Finance Receivables and Net Investment in Operating Leases, Before Allowance for Credit Losses	9,100	5,700
Allowance for Credit Losses	100	0
Finance Receivables and Net Investment In Operating Leases, After Allowance for Credit Losses	9,000	5,700
Related Debt	8,300	5,100
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	500	700
Allowance for Credit Losses	0	0
Finance Receivables and Net Investment In Operating Leases, After Allowance for Credit Losses	500	700
Related Debt	100	600
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