Finance Receivables and Loans, Net - Schedule of Financing Receivable Credit Quality Indicators Commercial (Details) - USD ($) $ in Millions	Jun. 30, 2025	Dec. 31, 2024
Financing Receivable, Credit Quality Indicator [Line Items]
Total finance receivables and loans	$ 133,229	$ 136,030
Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	1,176	2,197
Year two, originated, fiscal year before current fiscal year	2,198	1,652
Year three, originated, two years before current fiscal year	1,421	2,305
Year four, originated, three years before current fiscal year	2,120	1,739
Year five, originated, four years before current fiscal year	1,629	1,109
Originated, more than five years before current fiscal year	2,384	1,555
Revolving loans	20,895	22,032
Revolving loans converted to term	453	156
Total finance receivables and loans	32,276	32,745
Automotive | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	171	525
Year two, originated, fiscal year before current fiscal year	437	374
Year three, originated, two years before current fiscal year	318	352
Year four, originated, three years before current fiscal year	313	150
Year five, originated, four years before current fiscal year	134	67
Originated, more than five years before current fiscal year	98	53
Revolving loans	14,972	16,738
Revolving loans converted to term	0	0
Total finance receivables and loans	16,443	18,259
Automotive | Pass | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	170	522
Year two, originated, fiscal year before current fiscal year	433	336
Year three, originated, two years before current fiscal year	287	337
Year four, originated, three years before current fiscal year	298	125
Year five, originated, four years before current fiscal year	111	64
Originated, more than five years before current fiscal year	94	52
Revolving loans	13,437	15,005
Revolving loans converted to term	0	0
Total finance receivables and loans	14,830	16,441
Automotive | Special mention | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	1	3
Year two, originated, fiscal year before current fiscal year	4	38
Year three, originated, two years before current fiscal year	29	15
Year four, originated, three years before current fiscal year	13	25
Year five, originated, four years before current fiscal year	20	3
Originated, more than five years before current fiscal year	4	1
Revolving loans	1,441	1,694
Revolving loans converted to term	0	0
Total finance receivables and loans	1,512	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	2	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	0	0
Revolving loans	92	33
Revolving loans converted to term	0	0
Total finance receivables and loans	99	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	2	6
Revolving loans converted to term	0	0
Total finance receivables and loans	2	6
Other | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	280	707
Year two, originated, fiscal year before current fiscal year	700	323
Year three, originated, two years before current fiscal year	208	655
Year four, originated, three years before current fiscal year	560	502
Year five, originated, four years before current fiscal year	453	250
Originated, more than five years before current fiscal year	609	361
Revolving loans	5,923	5,294
Revolving loans converted to term	355	120
Total finance receivables and loans	9,088	8,212
Other | Pass | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	280	707
Year two, originated, fiscal year before current fiscal year	700	296
Year three, originated, two years before current fiscal year	208	261
Year four, originated, three years before current fiscal year	172	199
Year five, originated, four years before current fiscal year	241	18
Originated, more than five years before current fiscal year	397	205
Revolving loans	5,665	5,047
Revolving loans converted to term	335	84
Total finance receivables and loans	7,998	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	388	280
Year five, originated, four years before current fiscal year	192	186
Originated, more than five years before current fiscal year	67	76
Revolving loans	203	226
Revolving loans converted to term	20	32
Total finance receivables and loans	870	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	0	0
Year four, originated, three years before current fiscal year	0	23
Year five, originated, four years before current fiscal year	20	46
Originated, more than five years before current fiscal year	119	54
Revolving loans	41	12
Revolving loans converted to term	0	4
Total finance receivables and loans	180	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	14	9
Revolving loans converted to term	0	0
Total finance receivables and loans	40	35
Commercial real estate | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	725	965
Year two, originated, fiscal year before current fiscal year	1,061	955
Year three, originated, two years before current fiscal year	895	1,298
Year four, originated, three years before current fiscal year	1,247	1,087
Year five, originated, four years before current fiscal year	1,042	792
Originated, more than five years before current fiscal year	1,677	1,141
Revolving loans	0	0
Revolving loans converted to term	98	36
Total finance receivables and loans	6,745	6,274
Commercial real estate | Pass | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	725	959
Year two, originated, fiscal year before current fiscal year	1,031	904
Year three, originated, two years before current fiscal year	823	1,228
Year four, originated, three years before current fiscal year	1,146	1,030
Year five, originated, four years before current fiscal year	989	757
Originated, more than five years before current fiscal year	1,642	1,137
Revolving loans	0	0
Revolving loans converted to term	98	36
Total finance receivables and loans	6,454	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	30	51
Year three, originated, two years before current fiscal year	64	69
Year four, originated, three years before current fiscal year	93	57
Year five, originated, four years before current fiscal year	47	35
Originated, more than five years before current fiscal year	35	3
Revolving loans	0	0
Revolving loans converted to term	0	0
Total finance receivables and loans	269	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	8
Year four, originated, three years before current fiscal year	7
Year five, originated, four years before current fiscal year	6
Originated, more than five years before current fiscal year	0
Revolving loans	0
Revolving loans converted to term	0
Total finance receivables and loans	21
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	0	1
Revolving loans	0	0
Revolving loans converted to term	0	0
Total finance receivables and loans	$ 1	$ 2