Finance Receivables and Loans, Net - Schedule of Financing Receivable Credit Quality Indicators Commercial (Details) - USD ($) $ in Millions	Mar. 31, 2025	Dec. 31, 2024
Financing Receivable, Credit Quality Indicator [Line Items]
Total finance receivables and loans	$ 133,485	$ 136,030
Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	749	2,197
Year two, originated, fiscal year before current fiscal year	2,267	1,652
Year three, originated, two years before current fiscal year	1,524	2,305
Year four, originated, three years before current fiscal year	2,143	1,739
Year five, originated, four years before current fiscal year	1,667	1,109
Originated, more than five years before current fiscal year	2,593	1,555
Revolving loans	21,533	22,032
Revolving loans converted to term	178	156
Total finance receivables and loans	32,654	32,745
Automotive | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	49	525
Year two, originated, fiscal year before current fiscal year	512	374
Year three, originated, two years before current fiscal year	338	352
Year four, originated, three years before current fiscal year	330	150
Year five, originated, four years before current fiscal year	141	67
Originated, more than five years before current fiscal year	109	53
Revolving loans	15,460	16,738
Revolving loans converted to term	0	0
Total finance receivables and loans	16,939	18,259
Automotive | Pass | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	49	522
Year two, originated, fiscal year before current fiscal year	508	336
Year three, originated, two years before current fiscal year	311	337
Year four, originated, three years before current fiscal year	315	125
Year five, originated, four years before current fiscal year	117	64
Originated, more than five years before current fiscal year	104	52
Revolving loans	13,818	15,005
Revolving loans converted to term	0	0
Total finance receivables and loans	15,222	16,441
Automotive | Special mention | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	0	3
Year two, originated, fiscal year before current fiscal year	4	38
Year three, originated, two years before current fiscal year	26	15
Year four, originated, three years before current fiscal year	13	25
Year five, originated, four years before current fiscal year	21	3
Originated, more than five years before current fiscal year	4	1
Revolving loans	1,521	1,694
Revolving loans converted to term	0	0
Total finance receivables and loans	1,589	1,779
Automotive | Substandard | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	0	0
Year two, originated, fiscal year before current fiscal year	0	0
Year three, originated, two years before current fiscal year	1	0
Year four, originated, three years before current fiscal year	2	0
Year five, originated, four years before current fiscal year	3	0
Originated, more than five years before current fiscal year	1	0
Revolving loans	116	33
Revolving loans converted to term	0	0
Total finance receivables and loans	123	33
Automotive | Doubtful | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	0	0
Year two, originated, fiscal year before current fiscal year	0	0
Year three, originated, two years before current fiscal year	0	0
Year four, originated, three years before current fiscal year	0	0
Year five, originated, four years before current fiscal year	0	0
Originated, more than five years before current fiscal year	0	0
Revolving loans	5	6
Revolving loans converted to term	0	0
Total finance receivables and loans	5	6
Other | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	128	707
Year two, originated, fiscal year before current fiscal year	705	323
Year three, originated, two years before current fiscal year	275	655
Year four, originated, three years before current fiscal year	557	502
Year five, originated, four years before current fiscal year	467	250
Originated, more than five years before current fiscal year	648	361
Revolving loans	6,073	5,294
Revolving loans converted to term	131	120
Total finance receivables and loans	8,984	8,212
Other | Pass | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	128	707
Year two, originated, fiscal year before current fiscal year	705	296
Year three, originated, two years before current fiscal year	248	261
Year four, originated, three years before current fiscal year	194	199
Year five, originated, four years before current fiscal year	197	18
Originated, more than five years before current fiscal year	239	205
Revolving loans	5,793	5,047
Revolving loans converted to term	107	84
Total finance receivables and loans	7,611	6,817
Other | Special mention | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	0	0
Year two, originated, fiscal year before current fiscal year	0	0
Year three, originated, two years before current fiscal year	0	394
Year four, originated, three years before current fiscal year	363	280
Year five, originated, four years before current fiscal year	248	186
Originated, more than five years before current fiscal year	266	76
Revolving loans	247	226
Revolving loans converted to term	21	32
Total finance receivables and loans	1,145	1,194
Other | Substandard | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	0	0
Year two, originated, fiscal year before current fiscal year	0	27
Year three, originated, two years before current fiscal year	27	0
Year four, originated, three years before current fiscal year	0	23
Year five, originated, four years before current fiscal year	22	46
Originated, more than five years before current fiscal year	117	54
Revolving loans	24	12
Revolving loans converted to term	3	4
Total finance receivables and loans	193	166
Other | Doubtful | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	0	0
Year two, originated, fiscal year before current fiscal year	0	0
Year three, originated, two years before current fiscal year	0	0
Year four, originated, three years before current fiscal year	0	0
Year five, originated, four years before current fiscal year	0	0
Originated, more than five years before current fiscal year	26	26
Revolving loans	9	9
Revolving loans converted to term	0	0
Total finance receivables and loans	35	35
Commercial real estate | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	572	965
Year two, originated, fiscal year before current fiscal year	1,050	955
Year three, originated, two years before current fiscal year	911	1,298
Year four, originated, three years before current fiscal year	1,256	1,087
Year five, originated, four years before current fiscal year	1,059	792
Originated, more than five years before current fiscal year	1,836	1,141
Revolving loans	0	0
Revolving loans converted to term	47	36
Total finance receivables and loans	6,731	6,274
Commercial real estate | Pass | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	572	959
Year two, originated, fiscal year before current fiscal year	1,043	904
Year three, originated, two years before current fiscal year	866	1,228
Year four, originated, three years before current fiscal year	1,169	1,030
Year five, originated, four years before current fiscal year	1,012	757
Originated, more than five years before current fiscal year	1,797	1,137
Revolving loans	0	0
Revolving loans converted to term	47	36
Total finance receivables and loans	6,506	6,051
Commercial real estate | Special mention | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	0	6
Year two, originated, fiscal year before current fiscal year	7	51
Year three, originated, two years before current fiscal year	39	69
Year four, originated, three years before current fiscal year	78	57
Year five, originated, four years before current fiscal year	42	35
Originated, more than five years before current fiscal year	38	3
Revolving loans	0	0
Revolving loans converted to term	0	0
Total finance receivables and loans	204	221
Commercial real estate | Substandard | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	0
Year two, originated, fiscal year before current fiscal year	0
Year three, originated, two years before current fiscal year	6
Year four, originated, three years before current fiscal year	8
Year five, originated, four years before current fiscal year	5
Originated, more than five years before current fiscal year	0
Revolving loans	0
Revolving loans converted to term	0
Total finance receivables and loans	19
Commercial real estate | Doubtful | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	0	0
Year two, originated, fiscal year before current fiscal year	0	0
Year three, originated, two years before current fiscal year	0	1
Year four, originated, three years before current fiscal year	1	0
Year five, originated, four years before current fiscal year	0	0
Originated, more than five years before current fiscal year	1	1
Revolving loans	0	0
Revolving loans converted to term	0	0
Total finance receivables and loans	$ 2	$ 2