Finance Receivables - Credit Quality and Impaired Receivables (Details) - USD ($)	6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Dec. 31, 2024
Financing Receivable, Credit Quality Indicator [Line Items]
Non-Accrual of Revenue	90
Financing Receivables	$ 121,254,000,000		$ 122,814,000,000
Wholesale and Dealer Loans [Member] | Financing Receivable [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivables	4,000,000		8,000,000
Commercial Portfolio Segment [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivables	37,528,000,000		39,482,000,000
Financing Receivable, Revolving	34,130,000,000		36,347,000,000
Financing Receivable, Revolving, Writeoff	11,000,000	$ 6,000,000
Commercial Portfolio Segment [Member] | Group I
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivables	31,302,000,000		34,298,000,000
Financing Receivable, Revolving	30,431,000,000		33,345,000,000
Commercial Portfolio Segment [Member] | Group I | Percent of Total
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivables	0.891		0.917
Commercial Portfolio Segment [Member] | Group II
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivables	3,164,000,000		2,570,000,000
Financing Receivable, Revolving	3,044,000,000		2,494,000,000
Commercial Portfolio Segment [Member] | Group II | Percent of Total
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivables	0.090		0.069
Commercial Portfolio Segment [Member] | Group III
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivables	599,000,000		469,000,000
Financing Receivable, Revolving	590,000,000		462,000,000
Commercial Portfolio Segment [Member] | Group III | Percent of Total
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivables	0.017		0.013
Commercial Portfolio Segment [Member] | Group IV
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivables	66,000,000		47,000,000
Financing Receivable, Revolving	65,000,000		46,000,000
Commercial Portfolio Segment [Member] | Group IV | Percent of Total
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivables	0.002		0.001
Commercial Portfolio Segment [Member] | Dealer Loan
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	340,000,000		283,000,000
Financing Receivable, Originated Four Years before Latest Fiscal Year	87,000,000		63,000,000
Financing Receivable, Originated Three Years before Latest Fiscal Year	37,000,000		102,000,000
Financing Receivable, Originated Two Years before Latest Fiscal Year	231,000,000		48,000,000
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	129,000,000		260,000,000
Financing Receivable, Originated in Current Fiscal Year	177,000,000		281,000,000
Financing Receivable Originations Total	1,001,000,000		1,037,000,000
Commercial Portfolio Segment [Member] | Dealer Loan | Group I
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	315,000,000		270,000,000
Financing Receivable, Originated Four Years before Latest Fiscal Year	78,000,000		63,000,000
Financing Receivable, Originated Three Years before Latest Fiscal Year	34,000,000		97,000,000
Financing Receivable, Originated Two Years before Latest Fiscal Year	196,000,000		47,000,000
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	118,000,000		231,000,000
Financing Receivable, Originated in Current Fiscal Year	130,000,000		245,000,000
Financing Receivable Originations Total	871,000,000		953,000,000
Commercial Portfolio Segment [Member] | Dealer Loan | Group II
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	24,000,000		13,000,000
Financing Receivable, Originated Four Years before Latest Fiscal Year	9,000,000		0
Financing Receivable, Originated Three Years before Latest Fiscal Year	3,000,000		3,000,000
Financing Receivable, Originated Two Years before Latest Fiscal Year	35,000,000		1,000,000
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	10,000,000		28,000,000
Financing Receivable, Originated in Current Fiscal Year	39,000,000		31,000,000
Financing Receivable Originations Total	120,000,000		76,000,000
Commercial Portfolio Segment [Member] | Dealer Loan | Group III
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	1,000,000		0
Financing Receivable, Originated Four Years before Latest Fiscal Year	0		0
Financing Receivable, Originated Three Years before Latest Fiscal Year	0		2,000,000
Financing Receivable, Originated Two Years before Latest Fiscal Year	0		0
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	1,000,000		1,000,000
Financing Receivable, Originated in Current Fiscal Year	7,000,000		4,000,000
Financing Receivable Originations Total	9,000,000		7,000,000
Commercial Portfolio Segment [Member] | Dealer Loan | Group IV
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	0		0
Financing Receivable, Originated Four Years before Latest Fiscal Year	0		0
Financing Receivable, Originated Three Years before Latest Fiscal Year	0		0
Financing Receivable, Originated Two Years before Latest Fiscal Year	0		0
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	0		0
Financing Receivable, Originated in Current Fiscal Year	1,000,000		1,000,000
Financing Receivable Originations Total	1,000,000		1,000,000
Commercial Portfolio Segment [Member] | Commercial Portfolio Segment [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivables	35,131,000,000		37,384,000,000
Commercial Portfolio Segment [Member] | Commercial Portfolio Segment [Member] | Percent of Total
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivables	1.000		1.000
Commercial Portfolio Segment [Member] | Wholesale and Dealer Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivables	35,131,000,000		37,384,000,000
Financing Receivable, Allowance for Credit Loss, Writeoff	14,000,000		7,000,000
Commercial Portfolio Segment [Member] | Dealer Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Allowance for Credit Loss, Writeoff	3,000,000		1,000,000
Financing Receivable, Year One, Originated, Current Fiscal Year, Writeoff	0	0
Financing Receivable, Year Three, Originated, Two Years Before Current Fiscal Year, Writeoff	3,000,000	0
Financing Receivable, Year Four, Originated, Three Years Before Current Fiscal Year, Writeoff	0	0
Financing Receivable, Year Five, Originated, Four Years Before Current Fiscal Year, Writeoff	0	0
Financing Receivable, Originated, More Than Five Years before Current Fiscal Year, Writeoff	0	1,000,000
Financing Receivable, Year Two, Originated, Fiscal Year Before Current Fiscal Year, Writeoff	0	0
Consumer Portfolio Segment [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivables	83,726,000,000		83,332,000,000
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	2,382,000,000		846,000,000
Financing Receivable, Originated Four Years before Latest Fiscal Year	3,800,000,000		3,282,000,000
Financing Receivable, Originated Three Years before Latest Fiscal Year	9,403,000,000		5,604,000,000
Financing Receivable, Originated Two Years before Latest Fiscal Year	20,173,000,000		12,542,000,000
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	32,445,000,000		24,513,000,000
Financing Receivable, Originated in Current Fiscal Year	15,523,000,000		36,545,000,000
Financing Receivable, Allowance for Credit Loss, Writeoff	313,000,000		568,000,000
Financing Receivable, Year One, Originated, Current Fiscal Year, Writeoff	4,000,000	50,000,000
Financing Receivable, Year Three, Originated, Two Years Before Current Fiscal Year, Writeoff	92,000,000	152,000,000
Financing Receivable, Year Four, Originated, Three Years Before Current Fiscal Year, Writeoff	64,000,000	71,000,000
Financing Receivable, Year Five, Originated, Four Years Before Current Fiscal Year, Writeoff	30,000,000	58,000,000
Financing Receivable, Originated, More Than Five Years before Current Fiscal Year, Writeoff	31,000,000	46,000,000
Financing Receivable, Year Two, Originated, Fiscal Year Before Current Fiscal Year, Writeoff	92,000,000	$ 191,000,000
Consumer Portfolio Segment [Member] | Financing Receivables, 31-60 Days Past Due [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivables	808,000,000		872,000,000
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	84,000,000		43,000,000
Financing Receivable, Originated Four Years before Latest Fiscal Year	79,000,000		93,000,000
Financing Receivable, Originated Three Years before Latest Fiscal Year	148,000,000		104,000,000
Financing Receivable, Originated Two Years before Latest Fiscal Year	219,000,000		187,000,000
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	233,000,000		242,000,000
Financing Receivable, Originated in Current Fiscal Year	45,000,000		203,000,000
Consumer Portfolio Segment [Member] | Financing Receivables, Greater Than 120 Days Past Due [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivables	291,000,000		275,000,000
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	30,000,000		15,000,000
Financing Receivable, Originated Four Years before Latest Fiscal Year	31,000,000		27,000,000
Financing Receivable, Originated Three Years before Latest Fiscal Year	53,000,000		35,000,000
Financing Receivable, Originated Two Years before Latest Fiscal Year	76,000,000		57,000,000
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	78,000,000		82,000,000
Financing Receivable, Originated in Current Fiscal Year	23,000,000		59,000,000
Consumer Portfolio Segment [Member] | Total past due [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivables	1,099,000,000		1,147,000,000
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	114,000,000		58,000,000
Financing Receivable, Originated Four Years before Latest Fiscal Year	110,000,000		120,000,000
Financing Receivable, Originated Three Years before Latest Fiscal Year	201,000,000		139,000,000
Financing Receivable, Originated Two Years before Latest Fiscal Year	295,000,000		244,000,000
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	311,000,000		324,000,000
Financing Receivable, Originated in Current Fiscal Year	68,000,000		262,000,000
Consumer Portfolio Segment [Member] | Financial Asset, 1 to 29 Days Past Due [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivables	82,627,000,000		82,185,000,000
Financing Receivable, Originated Five or More Years before Latest Fiscal Year	2,268,000,000		788,000,000
Financing Receivable, Originated Four Years before Latest Fiscal Year	3,690,000,000		3,162,000,000
Financing Receivable, Originated Three Years before Latest Fiscal Year	9,202,000,000		5,465,000,000
Financing Receivable, Originated Two Years before Latest Fiscal Year	19,878,000,000		12,298,000,000
Financing Receivable, Originated in Fiscal Year before Latest Fiscal Year	32,134,000,000		24,189,000,000
Financing Receivable, Originated in Current Fiscal Year	15,455,000,000		36,283,000,000
Consumer Portfolio Segment [Member] | Percent of Total
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivables	1.000		1.000
Consumer Portfolio Segment [Member] | Percent of Total | Financing Receivables, 31-60 Days Past Due [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivables	0.010		0.010
Consumer Portfolio Segment [Member] | Percent of Total | Financing Receivables, Greater Than 120 Days Past Due [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivables	0.003		0.004
Consumer Portfolio Segment [Member] | Percent of Total | Total past due [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivables	0.013		0.014
Consumer Portfolio Segment [Member] | Percent of Total | Financial Asset, 1 to 29 Days Past Due [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivables	$ 0.987		$ 0.986