Finance Receivables and Loans, Net (Financing Receivable Credit Quality Indicators Commercial) (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Financing Receivable, Credit Quality Indicator [Line Items]
Total finance receivables and loans	$ 125,365	$ 122,268
Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	604	2,419
Year two, originated, fiscal year before current fiscal year	2,320	1,896
Year three, originated, two years before current fiscal year	1,835	1,586
Year four, originated, three years before current fiscal year	1,458	783
Year five, originated, four years before current fiscal year	691	663
Originated, more than five years before current fiscal year	1,574	1,052
Revolving loans	16,862	15,512
Revolving loans converted to term	152	131
Total finance receivables and loans	25,496	24,042
Automotive loan | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	70	354
Year two, originated, fiscal year before current fiscal year	352	192
Year three, originated, two years before current fiscal year	165	119
Year four, originated, three years before current fiscal year	101	65
Year five, originated, four years before current fiscal year	58	54
Originated, more than five years before current fiscal year	103	74
Revolving loans	12,648	11,371
Revolving loans converted to term	0	0
Total finance receivables and loans	13,497	12,229
Automotive loan | Pass | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	70	347
Year two, originated, fiscal year before current fiscal year	350	190
Year three, originated, two years before current fiscal year	163	112
Year four, originated, three years before current fiscal year	95	49
Year five, originated, four years before current fiscal year	45	23
Originated, more than five years before current fiscal year	61	56
Revolving loans	12,121	10,741
Revolving loans converted to term	0	0
Total finance receivables and loans	12,905	11,518
Automotive loan | Special Mention | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	0	7
Year two, originated, fiscal year before current fiscal year	2	1
Year three, originated, two years before current fiscal year	1	7
Year four, originated, three years before current fiscal year	5	15
Year five, originated, four years before current fiscal year	12	31
Originated, more than five years before current fiscal year	42	18
Revolving loans	469	589
Revolving loans converted to term	0	0
Total finance receivables and loans	531	668
Automotive loan | 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	1	0
Year four, originated, three years before current fiscal year	1	1
Year five, originated, four years before current fiscal year	1	0
Originated, more than five years before current fiscal year	0	0
Revolving loans	58	41
Revolving loans converted to term	0	0
Total finance receivables and loans	61	43
Other | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	232	754
Year two, originated, fiscal year before current fiscal year	676	639
Year three, originated, two years before current fiscal year	638	565
Year four, originated, three years before current fiscal year	478	107
Year five, originated, four years before current fiscal year	106	249
Originated, more than five years before current fiscal year	518	299
Revolving loans	4,206	4,138
Revolving loans converted to term	143	123
Total finance receivables and loans	6,997	6,874
Other | Pass | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	232	739
Year two, originated, fiscal year before current fiscal year	661	448
Year three, originated, two years before current fiscal year	447	374
Year four, originated, three years before current fiscal year	288	86
Year five, originated, four years before current fiscal year	62	99
Originated, more than five years before current fiscal year	137	68
Revolving loans	4,033	4,032
Revolving loans converted to term	99	83
Total finance receivables and loans	5,959	5,929
Other | Special Mention | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	0	15
Year two, originated, fiscal year before current fiscal year	15	169
Year three, originated, two years before current fiscal year	169	96
Year four, originated, three years before current fiscal year	96	21
Year five, originated, four years before current fiscal year	44	10
Originated, more than five years before current fiscal year	133	122
Revolving loans	111	93
Revolving loans converted to term	20	17
Total finance receivables and loans	588	543
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	22
Year three, originated, two years before current fiscal year	22	95
Year four, originated, three years before current fiscal year	94	0
Year five, originated, four years before current fiscal year	0	140
Originated, more than five years before current fiscal year	166	83
Revolving loans	55	13
Revolving loans converted to term	21	23
Total finance receivables and loans	358	376
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	82	26
Revolving loans	7	0
Revolving loans converted to term	3	0
Total finance receivables and loans	92	26
Commercial real estate | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	302	1,311
Year two, originated, fiscal year before current fiscal year	1,292	1,065
Year three, originated, two years before current fiscal year	1,032	902
Year four, originated, three years before current fiscal year	879	611
Year five, originated, four years before current fiscal year	527	360
Originated, more than five years before current fiscal year	953	679
Revolving loans	8	3
Revolving loans converted to term	9	8
Total finance receivables and loans	5,002	4,939
Commercial real estate | Pass | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	302	1,298
Year two, originated, fiscal year before current fiscal year	1,285	1,060
Year three, originated, two years before current fiscal year	1,027	873
Year four, originated, three years before current fiscal year	781	604
Year five, originated, four years before current fiscal year	523	342
Originated, more than five years before current fiscal year	919	653
Revolving loans	8	3
Revolving loans converted to term	9	8
Total finance receivables and loans	4,854	4,841
Commercial real estate | Special Mention | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	0	13
Year two, originated, fiscal year before current fiscal year	7	5
Year three, originated, two years before current fiscal year	5	29
Year four, originated, three years before current fiscal year	98	7
Year five, originated, four years before current fiscal year	4	18
Originated, more than five years before current fiscal year	30	19
Revolving loans	0	0
Revolving loans converted to term	0	0
Total finance receivables and loans	144	91
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	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	4	7
Revolving loans	0	0
Revolving loans converted to term	0	0
Total finance receivables and loans	$ 4	$ 7