Finance Receivables - Credit Quality and Impaired Receivables (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivables	$ 106,375,000,000	$ 114,830,000,000
Finance receivables before unearned interest supplements	8,431,000,000	8,566,000,000
Related Party Transaction, Expenses from Transactions with Related Party	(337,000,000)	(363,000,000)
Finance receivables, net	8,027,000,000	8,186,000,000
Sales-type Lease, Interest Income, Unguaranteed Residual Asset	2,893,000,000	2,795,000,000
Deferred Costs, Leasing, Gross	102,000,000	120,000,000
Sales-Type and Direct Financing Lease, Gross	5,436,000,000	5,651,000,000
Sales Type and Direct Financing Lease Revenue	357,000,000	380,000,000
Dealer Financing [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Past Due	99	62
Finance Leases Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Allowance for Credit Loss	(67,000,000)	(17,000,000)
Consumer Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivables	78,170,000,000
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	845,000,000
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	2,599,000,000
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	6,790,000,000
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	13,939,000,000
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	21,074,000,000
Financing Receivable, Year One, Originated, Current Fiscal Year	$ 32,923,000,000
Financing Receivable, Credit Quality, Range of Dates Ratings Updated	61 to 120 days
Consumer Segment [Member] | 31-60 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivables	$ 681,000,000
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	45,000,000
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	62,000,000
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	103,000,000
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	162,000,000
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	166,000,000
Financing Receivable, Year One, Originated, Current Fiscal Year	143,000,000
Consumer Segment [Member] | Financing Receivables, 61-120 Days past due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivables	163,000,000
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	7,000,000
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	12,000,000
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	24,000,000
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	44,000,000
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	45,000,000
Financing Receivable, Year One, Originated, Current Fiscal Year	31,000,000
Consumer Segment [Member] | Greater Than 120 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivables	41,000,000
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	11,000,000
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	6,000,000
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	7,000,000
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	8,000,000
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	7,000,000
Financing Receivable, Year One, Originated, Current Fiscal Year	2,000,000
Consumer Segment [Member] | Total past due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivables	885,000,000
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	63,000,000
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	80,000,000
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	134,000,000
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	214,000,000
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	218,000,000
Financing Receivable, Year One, Originated, Current Fiscal Year	176,000,000
Consumer Segment [Member] | Financial Asset, 1 to 29 Days Past Due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivables	77,285,000,000
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	782,000,000
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	2,519,000,000
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	6,656,000,000
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	13,725,000,000
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	20,856,000,000
Financing Receivable, Year One, Originated, Current Fiscal Year	$ 32,747,000,000
Consumer Segment [Member] | Pass [Member] | Maximum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance Receivables Credit Quality Ratings Term Range	60 days
Consumer Segment [Member] | Substandard [Member] | Minimum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Finance Receivables Credit Quality Ratings Term Range	120 days
Non-Consumer Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivables	$ 28,205,000,000	40,855,000,000
Financing Receivable, Revolving	24,996,000,000
Non-Consumer Segment [Member] | Group I [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivables	20,017,000,000
Financing Receivable, Revolving	18,769,000,000
Non-Consumer Segment [Member] | Group II [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivables	4,874,000,000
Financing Receivable, Revolving	4,680,000,000
Non-Consumer Segment [Member] | Group III [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivables	1,533,000,000
Financing Receivable, Revolving	1,464,000,000
Non-Consumer Segment [Member] | Group IV [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivables	93,000,000
Financing Receivable, Revolving	83,000,000
Non-Consumer Segment [Member] | Wholesale and Dealer Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivables	26,517,000,000	38,910,000,000
Non-Consumer Segment [Member] | Wholesale and Dealer Loans [Member] | Group I [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivables		31,206,000,000
Non-Consumer Segment [Member] | Wholesale and Dealer Loans [Member] | Group II [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivables		5,407,000,000
Non-Consumer Segment [Member] | Wholesale and Dealer Loans [Member] | Group III [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivables		2,108,000,000
Non-Consumer Segment [Member] | Wholesale and Dealer Loans [Member] | Group IV [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivables		$ 189,000,000
Non-Consumer Segment [Member] | Dealer Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	552,000,000
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	149,000,000
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	124,000,000
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	242,000,000
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	78,000,000
Financing Receivable, Year One, Originated, Current Fiscal Year	376,000,000
Financing Receivable Total	1,521,000,000
Non-Consumer Segment [Member] | Dealer Loan | Group I [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	503,000,000
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	129,000,000
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	110,000,000
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	188,000,000
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	70,000,000
Financing Receivable, Year One, Originated, Current Fiscal Year	248,000,000
Financing Receivable Total	1,248,000,000
Non-Consumer Segment [Member] | Dealer Loan | Group II [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	38,000,000
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	20,000,000
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	11,000,000
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	35,000,000
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	3,000,000
Financing Receivable, Year One, Originated, Current Fiscal Year	87,000,000
Financing Receivable Total	194,000,000
Non-Consumer Segment [Member] | Dealer Loan | Group III [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	9,000,000
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	3,000,000
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	19,000,000
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	3,000,000
Financing Receivable, Year One, Originated, Current Fiscal Year	35,000,000
Financing Receivable Total	69,000,000
Non-Consumer Segment [Member] | Dealer Loan | Group IV [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	2,000,000
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	0
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	0
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	2,000,000
Financing Receivable, Year One, Originated, Current Fiscal Year	6,000,000
Financing Receivable Total	10,000,000
Non-Consumer Segment [Member] | Non-Consumer Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivables	$ 26,517,000,000