Finance Receivables and Loans, Net - Schedule of Financing Receivable Credit Quality Indicators Consumer (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
Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Total finance receivables and loans	103,285	104,977
Consumer | Consumer automotive, excludes basis adjustment
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	30,919	31,450
Year two, originated, fiscal year before current fiscal year	21,604	25,350
Year three, originated, two years before current fiscal year	16,607	15,373
Year four, originated, three years before current fiscal year	9,247	6,555
Year five, originated, four years before current fiscal year	3,344	3,587
Originated, more than five years before current fiscal year	2,077	2,071
Revolving loans	0	0
Revolving loans converted to term	0	0
Total finance receivables and loans	83,798	84,386
Consumer | Consumer mortgage
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	13	153
Year two, originated, fiscal year before current fiscal year	33	2,181
Year three, originated, two years before current fiscal year	1,914	10,396
Year four, originated, three years before current fiscal year	9,856	1,843
Year five, originated, four years before current fiscal year	1,721	752
Originated, more than five years before current fiscal year	3,564	3,178
Revolving loans	116	145
Revolving loans converted to term	17	19
Total finance receivables and loans	17,234	18,667
Consumer | Other
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	0
Revolving loans	2,294	1,990
Revolving loans converted to term	0	0
Total finance receivables and loans	2,294	1,990
Consumer | Credit Card
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	0
Revolving loans	2,294	1,990
Revolving loans converted to term	0	0
Total finance receivables and loans	2,294	1,990
Consumer | Automotive
Financing Receivable, Credit Quality Indicator [Line Items]
Total finance receivables and loans	83,757	84,320
Liability excluded from amortized cost of hedged asset, portfolio layer method	41	66
Consumer Portfolio Segment, Excludes Basis Adjustment for Automotive Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	30,932	31,603
Year two, originated, fiscal year before current fiscal year	21,637	27,531
Year three, originated, two years before current fiscal year	18,521	25,769
Year four, originated, three years before current fiscal year	19,103	8,398
Year five, originated, four years before current fiscal year	5,065	4,339
Originated, more than five years before current fiscal year	5,641	5,249
Revolving loans	2,410	2,135
Revolving loans converted to term	17	19
Total finance receivables and loans	103,326	105,043
Current | Consumer | Consumer automotive, excludes basis adjustment
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	30,322	30,677
Year two, originated, fiscal year before current fiscal year	20,387	23,699
Year three, originated, two years before current fiscal year	15,234	14,209
Year four, originated, three years before current fiscal year	8,368	6,132
Year five, originated, four years before current fiscal year	3,064	3,306
Originated, more than five years before current fiscal year	1,849	1,876
Revolving loans	0	0
Revolving loans converted to term	0	0
Total finance receivables and loans	79,224	79,899
Current | Consumer | Consumer mortgage
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	13	152
Year two, originated, fiscal year before current fiscal year	31	2,170
Year three, originated, two years before current fiscal year	1,901	10,374
Year four, originated, three years before current fiscal year	9,834	1,836
Year five, originated, four years before current fiscal year	1,714	747
Originated, more than five years before current fiscal year	3,503	3,124
Revolving loans	115	142
Revolving loans converted to term	15	17
Total finance receivables and loans	17,126	18,562
Current | Consumer | Credit Card
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	0
Revolving loans	2,140	1,828
Revolving loans converted to term	0	0
Total finance receivables and loans	2,140	1,828
30–59 days past due | Consumer | Consumer automotive, excludes basis adjustment
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	419	539
Year two, originated, fiscal year before current fiscal year	756	1,041
Year three, originated, two years before current fiscal year	841	739
Year four, originated, three years before current fiscal year	546	270
Year five, originated, four years before current fiscal year	174	181
Originated, more than five years before current fiscal year	141	122
Revolving loans	0	0
Revolving loans converted to term	0	0
Total finance receivables and loans	2,877	2,892
30–59 days past due | Consumer | Consumer mortgage
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	0	1
Year two, originated, fiscal year before current fiscal year	0	8
Year three, originated, two years before current fiscal year	7	14
Year four, originated, three years before current fiscal year	9	3
Year five, originated, four years before current fiscal year	5	3
Originated, more than five years before current fiscal year	27	23
Revolving loans	0	0
Revolving loans converted to term	0	1
Total finance receivables and loans	48	53
30–59 days past due | Consumer | Credit Card
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	0
Revolving loans	35	39
Revolving loans converted to term	0	0
Total finance receivables and loans	35	39
60–89 days past due | Consumer | Consumer automotive, excludes basis adjustment
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	131	170
Year two, originated, fiscal year before current fiscal year	338	443
Year three, originated, two years before current fiscal year	390	303
Year four, originated, three years before current fiscal year	240	109
Year five, originated, four years before current fiscal year	75	68
Originated, more than five years before current fiscal year	56	45
Revolving loans	0	0
Revolving loans converted to term	0	0
Total finance receivables and loans	1,230	1,138
60–89 days past due | Consumer | Consumer mortgage
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	2
Year three, originated, two years before current fiscal year	4	4
Year four, originated, three years before current fiscal year	4	3
Year five, originated, four years before current fiscal year	1	0
Originated, more than five years before current fiscal year	4	6
Revolving loans	0	1
Revolving loans converted to term	0	0
Total finance receivables and loans	13	16
60–89 days past due | Consumer | Credit Card
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	0
Revolving loans	33	34
Revolving loans converted to term	0	0
Total finance receivables and loans	33	34
90 or more days past due | Consumer | Consumer automotive, excludes basis adjustment
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	47	64
Year two, originated, fiscal year before current fiscal year	123	167
Year three, originated, two years before current fiscal year	142	122
Year four, originated, three years before current fiscal year	93	44
Year five, originated, four years before current fiscal year	31	32
Originated, more than five years before current fiscal year	31	28
Revolving loans	0	0
Revolving loans converted to term	0	0
Total finance receivables and loans	467	457
90 or more days past due | Consumer | Consumer mortgage
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	0	0
Year two, originated, fiscal year before current fiscal year	2	1
Year three, originated, two years before current fiscal year	2	4
Year four, originated, three years before current fiscal year	9	1
Year five, originated, four years before current fiscal year	1	2
Originated, more than five years before current fiscal year	30	25
Revolving loans	1	2
Revolving loans converted to term	2	1
Total finance receivables and loans	47	36
90 or more days past due | Consumer | Credit Card
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	0
Revolving loans	86	89
Revolving loans converted to term	0	0
Total finance receivables and loans	$ 86	$ 89