Finance Receivables - Contractual Maturities (Details) - USD ($)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Finance Receivables Maturity [Abstract]
Financing Receivable, Gross	$ 122,814,000,000	$ 113,705,000,000
Finance receivables before unearned interest supplements	8,357,000,000	7,793,000,000
Financing Receivable, Allowance for Credit Losses, Write-downs	575,000,000	405,000,000
Consumer Segment [Member]
Finance Receivables Maturity [Abstract]
Financing Receivable, Gross	83,332,000,000	78,392,000,000
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	3,282,000,000	2,424,000,000
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	5,604,000,000	7,562,000,000
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	12,542,000,000	11,497,000,000
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	24,513,000,000	20,536,000,000
Financing Receivable, Year One, Originated, Current Fiscal Year	36,545,000,000	35,426,000,000
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	846,000,000	947,000,000
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year, Writeoff	71,000,000	75,000,000
Financing Receivable, Allowance for Credit Losses, Write-downs	568,000,000	401,000,000
Financing Receivable, Originated, More than Five Years before Current Fiscal Year, Writeoff	46,000,000	47,000,000
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year, Writeoff	58,000,000	40,000,000
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year, Writeoff	152,000,000	85,000,000
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year, Writeoff	191,000,000	117,000,000
Financing Receivable, Year One, Originated, Current Fiscal Year, Writeoff	50,000,000	37,000,000
Consumer Segment [Member] | Percent of Total
Finance Receivables Maturity [Abstract]
Financing Receivable, Gross	1.000	1.000
Consumer Segment [Member] | 31-60 Days Past Due [Member]
Finance Receivables Maturity [Abstract]
Financing Receivable, Gross	872,000,000	690,000,000
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	93,000,000	49,000,000
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	104,000,000	130,000,000
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	187,000,000	125,000,000
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	242,000,000	187,000,000
Financing Receivable, Year One, Originated, Current Fiscal Year	203,000,000	159,000,000
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	43,000,000	40,000,000
Consumer Segment [Member] | 31-60 Days Past Due [Member] | Percent of Total
Finance Receivables Maturity [Abstract]
Financing Receivable, Gross	0.010	0.009
Consumer Segment [Member] | Financing Receivables, 61-120 Days past due [Member]
Finance Receivables Maturity [Abstract]
Financing Receivable, Gross	225,000,000	195,000,000
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	20,000,000	11,000,000
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	27,000,000	30,000,000
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	46,000,000	37,000,000
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	70,000,000	58,000,000
Financing Receivable, Year One, Originated, Current Fiscal Year	54,000,000	50,000,000
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	8,000,000	9,000,000
Consumer Segment [Member] | Financing Receivables, 61-120 Days past due [Member] | Percent of Total
Finance Receivables Maturity [Abstract]
Financing Receivable, Gross	0.003	0.002
Consumer Segment [Member] | Greater Than 120 Days Past Due [Member]
Finance Receivables Maturity [Abstract]
Financing Receivable, Gross	50,000,000	43,000,000
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	7,000,000	4,000,000
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	8,000,000	7,000,000
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	11,000,000	10,000,000
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	12,000,000	10,000,000
Financing Receivable, Year One, Originated, Current Fiscal Year	5,000,000	5,000,000
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	7,000,000	7,000,000
Consumer Segment [Member] | Greater Than 120 Days Past Due [Member] | Percent of Total
Finance Receivables Maturity [Abstract]
Financing Receivable, Gross	0.001	0.001
Consumer Segment [Member] | Total past due [Member]
Finance Receivables Maturity [Abstract]
Financing Receivable, Gross	1,147,000,000	928,000,000
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	120,000,000	64,000,000
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	139,000,000	167,000,000
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	244,000,000	172,000,000
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	324,000,000	255,000,000
Financing Receivable, Year One, Originated, Current Fiscal Year	262,000,000	214,000,000
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	58,000,000	56,000,000
Consumer Segment [Member] | Total past due [Member] | Percent of Total
Finance Receivables Maturity [Abstract]
Financing Receivable, Gross	0.014	0.012
Consumer Segment [Member] | Financial Asset, 1 to 29 Days Past Due [Member]
Finance Receivables Maturity [Abstract]
Financing Receivable, Gross	82,185,000,000	77,464,000,000
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	3,162,000,000	2,360,000,000
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	5,465,000,000	7,395,000,000
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	12,298,000,000	11,325,000,000
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	24,189,000,000	20,281,000,000
Financing Receivable, Year One, Originated, Current Fiscal Year	36,283,000,000	35,212,000,000
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	788,000,000	891,000,000
Consumer Segment [Member] | Financial Asset, 1 to 29 Days Past Due [Member] | Percent of Total
Finance Receivables Maturity [Abstract]
Financing Receivable, Gross	0.986	0.988
Consumer Segment [Member] | Retail [Member]
Finance Receivables Maturity [Abstract]
Financing Receivable, Gross	83,332,000,000	78,392,000,000
Finance receivables before unearned interest supplements	87,930,000,000	81,736,000,000
Non-Consumer Segment [Member]
Finance Receivables Maturity [Abstract]
Financing Receivable, Gross	39,482,000,000	35,313,000,000
Financing Receivable, Allowance for Credit Losses, Write-downs	7,000,000	4,000,000
Non-Consumer Segment [Member] | Wholesale and Dealer Loans [Member]
Finance Receivables Maturity [Abstract]
Financing Receivable, Gross	37,384,000,000	33,377,000,000
Non-Consumer Segment [Member] | Other Finance Receivables [Member]
Finance Receivables Maturity [Abstract]
Financing Receivable, Gross	$ 2,098,000,000	$ 1,936,000,000