Finance Receivables and Loans, Net (Financing Receivable Credit Quality Indicators Commercial) (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Financing Receivable, Credit Quality Indicator [Line Items]
Total finance receivables and loans	$ 137,960	$ 139,439
Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	457	1,820
Year two, originated, fiscal year before current fiscal year	1,847	2,845
Year three, originated, two years before current fiscal year	2,766	1,929
Year four, originated, three years before current fiscal year	1,896	1,597
Year five, originated, four years before current fiscal year	1,440	1,002
Originated, more than five years before current fiscal year	2,081	1,223
Revolving loans	23,413	23,811
Revolving loans converted to term	251	235
Total finance receivables and loans	34,151	34,462
Automotive | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	198	515
Year two, originated, fiscal year before current fiscal year	475	520
Year three, originated, two years before current fiscal year	488	195
Year four, originated, three years before current fiscal year	181	98
Year five, originated, four years before current fiscal year	90	59
Originated, more than five years before current fiscal year	85	37
Revolving loans	17,646	17,276
Revolving loans converted to term	0	0
Total finance receivables and loans	19,163	18,700
Automotive | Pass | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	197	509
Year two, originated, fiscal year before current fiscal year	470	512
Year three, originated, two years before current fiscal year	481	165
Year four, originated, three years before current fiscal year	152	97
Year five, originated, four years before current fiscal year	89	58
Originated, more than five years before current fiscal year	71	22
Revolving loans	16,790	16,446
Revolving loans converted to term	0	0
Total finance receivables and loans	18,250	17,809
Automotive | Special mention | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	1	6
Year two, originated, fiscal year before current fiscal year	5	7
Year three, originated, two years before current fiscal year	7	30
Year four, originated, three years before current fiscal year	29	1
Year five, originated, four years before current fiscal year	1	1
Originated, more than five years before current fiscal year	13	14
Revolving loans	760	723
Revolving loans converted to term	0	0
Total finance receivables and loans	816	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	39	44
Revolving loans converted to term	0	0
Total finance receivables and loans	39	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	1	1
Revolving loans	57	63
Revolving loans converted to term	0	0
Total finance receivables and loans	58	64
Other | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	87	331
Year two, originated, fiscal year before current fiscal year	327	854
Year three, originated, two years before current fiscal year	815	577
Year four, originated, three years before current fiscal year	573	614
Year five, originated, four years before current fiscal year	480	318
Originated, more than five years before current fiscal year	641	374
Revolving loans	5,767	6,435
Revolving loans converted to term	221	209
Total finance receivables and loans	8,911	9,712
Other | Pass | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	87	331
Year two, originated, fiscal year before current fiscal year	300	646
Year three, originated, two years before current fiscal year	588	343
Year four, originated, three years before current fiscal year	310	405
Year five, originated, four years before current fiscal year	242	266
Originated, more than five years before current fiscal year	378	180
Revolving loans	5,538	6,202
Revolving loans converted to term	182	173
Total finance receivables and loans	7,625	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	227	188
Year four, originated, three years before current fiscal year	218	206
Year five, originated, four years before current fiscal year	181	51
Originated, more than five years before current fiscal year	153	85
Revolving loans	193	198
Revolving loans converted to term	28	25
Total finance receivables and loans	1,000	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	45	3
Year five, originated, four years before current fiscal year	57	0
Originated, more than five years before current fiscal year	83	83
Revolving loans	26	25
Revolving loans converted to term	11	11
Total finance receivables and loans	249	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	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	1
Originated, more than five years before current fiscal year	1	0
Revolving loans	0	0
Revolving loans converted to term	0	0
Total finance receivables and loans	1	1
Commercial real estate | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	172	974
Year two, originated, fiscal year before current fiscal year	1,045	1,471
Year three, originated, two years before current fiscal year	1,463	1,157
Year four, originated, three years before current fiscal year	1,142	885
Year five, originated, four years before current fiscal year	870	625
Originated, more than five years before current fiscal year	1,355	812
Revolving loans	0	100
Revolving loans converted to term	30	26
Total finance receivables and loans	6,077	6,050
Commercial real estate | Pass | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	172	971
Year two, originated, fiscal year before current fiscal year	1,037	1,452
Year three, originated, two years before current fiscal year	1,445	1,129
Year four, originated, three years before current fiscal year	1,115	884
Year five, originated, four years before current fiscal year	865	607
Originated, more than five years before current fiscal year	1,337	811
Revolving loans	0	100
Revolving loans converted to term	30	26
Total finance receivables and loans	6,001	5,980
Commercial real estate | 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	8	16
Year three, originated, two years before current fiscal year	18	28
Year four, originated, three years before current fiscal year	27	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	75	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	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	1	1
Revolving loans	0	0
Revolving loans converted to term	0	0
Total finance receivables and loans	$ 1	$ 4