Finance Receivables and Loans, Net (Financing Receivable Credit Quality Indicators Commercial) (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Financing Receivable, Credit Quality Indicator [Line Items]
Total finance receivables and loans	$ 140,260	$ 135,748
Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	1,504	2,915
Year two, originated, fiscal year before current fiscal year	2,818	2,035
Year three, originated, two years before current fiscal year	1,963	1,871
Year four, originated, three years before current fiscal year	1,486	1,406
Year five, originated, four years before current fiscal year	1,148	508
Originated, more than five years before current fiscal year	1,375	1,196
Revolving loans	21,399	19,057
Revolving loans converted to term	224	150
Total finance receivables and loans	31,917	29,138
Automotive | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	398	663
Year two, originated, fiscal year before current fiscal year	531	258
Year three, originated, two years before current fiscal year	205	132
Year four, originated, three years before current fiscal year	103	79
Year five, originated, four years before current fiscal year	63	38
Originated, more than five years before current fiscal year	47	55
Revolving loans	15,258	13,370
Revolving loans converted to term	0	0
Total finance receivables and loans	16,605	14,595
Automotive | Pass | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	394	640
Year two, originated, fiscal year before current fiscal year	522	211
Year three, originated, two years before current fiscal year	174	132
Year four, originated, three years before current fiscal year	103	78
Year five, originated, four years before current fiscal year	63	28
Originated, more than five years before current fiscal year	26	34
Revolving loans	14,511	12,327
Revolving loans converted to term	0	0
Total finance receivables and loans	15,793	13,450
Automotive | Special mention | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	4	23
Year two, originated, fiscal year before current fiscal year	8	47
Year three, originated, two years before current fiscal year	31	0
Year four, originated, three years before current fiscal year	0	0
Year five, originated, four years before current fiscal year	0	10
Originated, more than five years before current fiscal year	15	21
Revolving loans	640	1,016
Revolving loans converted to term	0	0
Total finance receivables and loans	698	1,117
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	1	0
Year three, originated, two years before current fiscal year	0	0
Year four, originated, three years before current fiscal year	0	1
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	27
Revolving loans converted to term	0	0
Total finance receivables and loans	40	28
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	6
Revolving loans	68
Revolving loans converted to term	0
Total finance receivables and loans	74
Other | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	356	771
Year two, originated, fiscal year before current fiscal year	744	627
Year three, originated, two years before current fiscal year	589	786
Year four, originated, three years before current fiscal year	480	629
Year five, originated, four years before current fiscal year	414	101
Originated, more than five years before current fiscal year	464	425
Revolving loans	6,141	5,678
Revolving loans converted to term	188	137
Total finance receivables and loans	9,376	9,154
Other | Pass | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	356	594
Year two, originated, fiscal year before current fiscal year	530	469
Year three, originated, two years before current fiscal year	359	607
Year four, originated, three years before current fiscal year	269	419
Year five, originated, four years before current fiscal year	337	54
Originated, more than five years before current fiscal year	179	133
Revolving loans	5,869	5,344
Revolving loans converted to term	144	89
Total finance receivables and loans	8,043	7,709
Other | Special mention | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	0	177
Year two, originated, fiscal year before current fiscal year	214	158
Year three, originated, two years before current fiscal year	179	175
Year four, originated, three years before current fiscal year	208	95
Year five, originated, four years before current fiscal year	51	47
Originated, more than five years before current fiscal year	145	128
Revolving loans	239	278
Revolving loans converted to term	26	35
Total finance receivables and loans	1,062	1,093
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	0
Year three, originated, two years before current fiscal year	51	4
Year four, originated, three years before current fiscal year	3	51
Year five, originated, four years before current fiscal year	26	0
Originated, more than five years before current fiscal year	83	139
Revolving loans	24	55
Revolving loans converted to term	18	13
Total finance receivables and loans	205	262
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	64
Year five, originated, four years before current fiscal year	0	0
Originated, more than five years before current fiscal year	57	25
Revolving loans	9	0
Revolving loans converted to term	0	0
Total finance receivables and loans	66	89
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		0
Originated, more than five years before current fiscal year		0
Revolving loans		1
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	750	1,481
Year two, originated, fiscal year before current fiscal year	1,543	1,150
Year three, originated, two years before current fiscal year	1,169	953
Year four, originated, three years before current fiscal year	903	698
Year five, originated, four years before current fiscal year	671	369
Originated, more than five years before current fiscal year	864	716
Revolving loans	0	9
Revolving loans converted to term	36	13
Total finance receivables and loans	5,936	5,389
Commercial real estate | Pass | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	748	1,481
Year two, originated, fiscal year before current fiscal year	1,533	1,118
Year three, originated, two years before current fiscal year	1,141	951
Year four, originated, three years before current fiscal year	901	679
Year five, originated, four years before current fiscal year	653	369
Originated, more than five years before current fiscal year	863	716
Revolving loans	0	9
Revolving loans converted to term	36	13
Total finance receivables and loans	5,875	5,336
Commercial real estate | Special mention | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	2	0
Year two, originated, fiscal year before current fiscal year	7	32
Year three, originated, two years before current fiscal year	28	2
Year four, originated, three years before current fiscal year	2	19
Year five, originated, four years before current fiscal year	18	0
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	58	$ 53
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	0
Revolving loans	0
Revolving loans converted to term	0
Total finance receivables and loans	$ 3