Finance Receivables and Loans, Net - Schedule of Financing Receivable Credit Quality Indicators Commercial (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Financing Receivable, Credit Quality Indicator [Line Items]
Total finance receivables and loans	$ 136,030	$ 139,439
Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	2,197	1,820
Year two, originated, fiscal year before current fiscal year	1,652	2,845
Year three, originated, two years before current fiscal year	2,305	1,929
Year four, originated, three years before current fiscal year	1,739	1,597
Year five, originated, four years before current fiscal year	1,109	1,002
Originated, more than five years before current fiscal year	1,555	1,223
Revolving loans	22,032	23,811
Revolving loans converted to term	156	235
Total finance receivables and loans	32,745	34,462
Automotive | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	525	515
Year two, originated, fiscal year before current fiscal year	374	520
Year three, originated, two years before current fiscal year	352	195
Year four, originated, three years before current fiscal year	150	98
Year five, originated, four years before current fiscal year	67	59
Originated, more than five years before current fiscal year	53	37
Revolving loans	16,738	17,276
Revolving loans converted to term	0	0
Total finance receivables and loans	18,259	18,700
Automotive | Pass | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	522	509
Year two, originated, fiscal year before current fiscal year	336	512
Year three, originated, two years before current fiscal year	337	165
Year four, originated, three years before current fiscal year	125	97
Year five, originated, four years before current fiscal year	64	58
Originated, more than five years before current fiscal year	52	22
Revolving loans	15,005	16,446
Revolving loans converted to term	0	0
Total finance receivables and loans	16,441	17,809
Automotive | Special mention | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	3	6
Year two, originated, fiscal year before current fiscal year	38	7
Year three, originated, two years before current fiscal year	15	30
Year four, originated, three years before current fiscal year	25	1
Year five, originated, four years before current fiscal year	3	1
Originated, more than five years before current fiscal year	1	14
Revolving loans	1,694	723
Revolving loans converted to term	0	0
Total finance receivables and loans	1,779	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	33	44
Revolving loans converted to term	0	0
Total finance receivables and loans	33	45
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	1
Revolving loans	6	63
Revolving loans converted to term	0	0
Total finance receivables and loans	6	64
Other | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	707	331
Year two, originated, fiscal year before current fiscal year	323	854
Year three, originated, two years before current fiscal year	655	577
Year four, originated, three years before current fiscal year	502	614
Year five, originated, four years before current fiscal year	250	318
Originated, more than five years before current fiscal year	361	374
Revolving loans	5,294	6,435
Revolving loans converted to term	120	209
Total finance receivables and loans	8,212	9,712
Other | Pass | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	707	331
Year two, originated, fiscal year before current fiscal year	296	646
Year three, originated, two years before current fiscal year	261	343
Year four, originated, three years before current fiscal year	199	405
Year five, originated, four years before current fiscal year	18	266
Originated, more than five years before current fiscal year	205	180
Revolving loans	5,047	6,202
Revolving loans converted to term	84	173
Total finance receivables and loans	6,817	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	394	188
Year four, originated, three years before current fiscal year	280	206
Year five, originated, four years before current fiscal year	186	51
Originated, more than five years before current fiscal year	76	85
Revolving loans	226	198
Revolving loans converted to term	32	25
Total finance receivables and loans	1,194	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	23	3
Year five, originated, four years before current fiscal year	46	0
Originated, more than five years before current fiscal year	54	83
Revolving loans	12	25
Revolving loans converted to term	4	11
Total finance receivables and loans	166	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	9	10
Revolving loans converted to term	0	0
Total finance receivables and loans	35	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	965	974
Year two, originated, fiscal year before current fiscal year	955	1,471
Year three, originated, two years before current fiscal year	1,298	1,157
Year four, originated, three years before current fiscal year	1,087	885
Year five, originated, four years before current fiscal year	792	625
Originated, more than five years before current fiscal year	1,141	812
Revolving loans	0	100
Revolving loans converted to term	36	26
Total finance receivables and loans	6,274	6,050
Commercial real estate | Pass | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	959	971
Year two, originated, fiscal year before current fiscal year	904	1,452
Year three, originated, two years before current fiscal year	1,228	1,129
Year four, originated, three years before current fiscal year	1,030	884
Year five, originated, four years before current fiscal year	757	607
Originated, more than five years before current fiscal year	1,137	811
Revolving loans	0	100
Revolving loans converted to term	36	26
Total finance receivables and loans	6,051	5,980
Commercial real estate | Special mention | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	6	3
Year two, originated, fiscal year before current fiscal year	51	16
Year three, originated, two years before current fiscal year	69	28
Year four, originated, three years before current fiscal year	57	1
Year five, originated, four years before current fiscal year	35	18
Originated, more than five years before current fiscal year	3	0
Revolving loans	0	0
Revolving loans converted to term	0	0
Total finance receivables and loans	221	66
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		3
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		$ 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	1
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	$ 2