Finance Receivables and Loans, Net - Schedule of Financing Receivable Credit Quality Indicators Commercial (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Financing Receivable, Credit Quality Indicator [Line Items]
Total finance receivables and loans	$ 138,783	$ 139,439
Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	1,054	1,820
Year two, originated, fiscal year before current fiscal year	1,794	2,845
Year three, originated, two years before current fiscal year	2,566	1,929
Year four, originated, three years before current fiscal year	1,827	1,597
Year five, originated, four years before current fiscal year	1,366	1,002
Originated, more than five years before current fiscal year	1,908	1,223
Revolving loans	24,450	23,811
Revolving loans converted to term	233	235
Total finance receivables and loans	35,198	34,462
Automotive | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	348	515
Year two, originated, fiscal year before current fiscal year	439	520
Year three, originated, two years before current fiscal year	454	195
Year four, originated, three years before current fiscal year	168	98
Year five, originated, four years before current fiscal year	83	59
Originated, more than five years before current fiscal year	76	37
Revolving loans	18,983	17,276
Revolving loans converted to term	0	0
Total finance receivables and loans	20,551	18,700
Automotive | Pass | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	343	509
Year two, originated, fiscal year before current fiscal year	416	512
Year three, originated, two years before current fiscal year	420	165
Year four, originated, three years before current fiscal year	146	97
Year five, originated, four years before current fiscal year	80	58
Originated, more than five years before current fiscal year	64	22
Revolving loans	17,869	16,446
Revolving loans converted to term	0	0
Total finance receivables and loans	19,338	17,809
Automotive | Special mention | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	5	6
Year two, originated, fiscal year before current fiscal year	23	7
Year three, originated, two years before current fiscal year	34	30
Year four, originated, three years before current fiscal year	22	1
Year five, originated, four years before current fiscal year	3	1
Originated, more than five years before current fiscal year	12	14
Revolving loans	1,045	723
Revolving loans converted to term	0	0
Total finance receivables and loans	1,144	782
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	1
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	69	44
Revolving loans converted to term	0	0
Total finance receivables and loans	69	45
Automotive | Doubtful | 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		0
Year four, originated, three years before current fiscal year		0
Year five, originated, four years before current fiscal year		0
Originated, more than five years before current fiscal year		1
Revolving loans		63
Revolving loans converted to term		0
Total finance receivables and loans		64
Other | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	335	331
Year two, originated, fiscal year before current fiscal year	325	854
Year three, originated, two years before current fiscal year	720	577
Year four, originated, three years before current fiscal year	538	614
Year five, originated, four years before current fiscal year	423	318
Originated, more than five years before current fiscal year	523	374
Revolving loans	5,367	6,435
Revolving loans converted to term	206	209
Total finance receivables and loans	8,437	9,712
Other | Pass | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	335	331
Year two, originated, fiscal year before current fiscal year	298	646
Year three, originated, two years before current fiscal year	358	343
Year four, originated, three years before current fiscal year	300	405
Year five, originated, four years before current fiscal year	193	266
Originated, more than five years before current fiscal year	302	180
Revolving loans	5,183	6,202
Revolving loans converted to term	176	173
Total finance receivables and loans	7,145	8,546
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	208
Year three, originated, two years before current fiscal year	362	188
Year four, originated, three years before current fiscal year	194	206
Year five, originated, four years before current fiscal year	173	51
Originated, more than five years before current fiscal year	111	85
Revolving loans	153	198
Revolving loans converted to term	19	25
Total finance receivables and loans	1,012	961
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	27	0
Year three, originated, two years before current fiscal year	0	46
Year four, originated, three years before current fiscal year	44	3
Year five, originated, four years before current fiscal year	57	0
Originated, more than five years before current fiscal year	84	83
Revolving loans	21	25
Revolving loans converted to term	11	11
Total finance receivables and loans	244	168
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	10	10
Revolving loans converted to term	0	0
Total finance receivables and loans	36	36
Other | Loss | 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		0
Year four, originated, three years before current fiscal year		0
Year five, originated, four years before current fiscal year		1
Originated, more than five years before current fiscal year		0
Revolving loans		0
Revolving loans converted to term		0
Total finance receivables and loans		1
Commercial real estate | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	371	974
Year two, originated, fiscal year before current fiscal year	1,030	1,471
Year three, originated, two years before current fiscal year	1,392	1,157
Year four, originated, three years before current fiscal year	1,121	885
Year five, originated, four years before current fiscal year	860	625
Originated, more than five years before current fiscal year	1,309	812
Revolving loans	100	100
Revolving loans converted to term	27	26
Total finance receivables and loans	6,210	6,050
Commercial real estate | Pass | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	370	971
Year two, originated, fiscal year before current fiscal year	1,018	1,452
Year three, originated, two years before current fiscal year	1,330	1,129
Year four, originated, three years before current fiscal year	1,099	884
Year five, originated, four years before current fiscal year	855	607
Originated, more than five years before current fiscal year	1,291	811
Revolving loans	100	100
Revolving loans converted to term	27	26
Total finance receivables and loans	6,090	5,980
Commercial real estate | 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	12	16
Year three, originated, two years before current fiscal year	61	28
Year four, originated, three years before current fiscal year	22	1
Year five, originated, four years before current fiscal year	5	18
Originated, more than five years before current fiscal year	17	0
Revolving loans	0	0
Revolving loans converted to term	0	0
Total finance receivables and loans	118	66
Commercial real estate | 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	3
Year three, originated, two years before current fiscal year	1	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	1
Revolving loans	0	0
Revolving loans converted to term	0	0
Total finance receivables and loans	1	$ 4
Commercial real estate | Doubtful | 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	0
Year four, originated, three years before current fiscal year	0
Year five, originated, four years before current fiscal year	0
Originated, more than five years before current fiscal year	1
Revolving loans	0
Revolving loans converted to term	0
Total finance receivables and loans	$ 1