Finance Receivables and Loans, Net (Financing Receivable Credit Quality Indicators Consumer) (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
Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Total finance receivables and loans	103,809	104,977
Consumer | Consumer automotive, excludes basis adjustment
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	8,558	31,450
Year two, originated, fiscal year before current fiscal year	28,638	25,350
Year three, originated, two years before current fiscal year	22,802	15,373
Year four, originated, three years before current fiscal year	13,571	6,555
Year five, originated, four years before current fiscal year	5,578	3,587
Originated, more than five years before current fiscal year	4,419	2,071
Revolving loans	0	0
Revolving loans converted to term	0	0
Total finance receivables and loans	83,566	84,386
Liability excluded from amortized cost of hedged asset, portfolio layer method	160	66
Consumer | Consumer mortgage
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	34	153
Year two, originated, fiscal year before current fiscal year	149	2,181
Year three, originated, two years before current fiscal year	2,160	10,396
Year four, originated, three years before current fiscal year	10,273	1,843
Year five, originated, four years before current fiscal year	1,821	752
Originated, more than five years before current fiscal year	3,849	3,178
Revolving loans	137	145
Revolving loans converted to term	18	19
Total finance receivables and loans	18,441	18,667
Consumer | Mortgage Finance
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	34	153
Year two, originated, fiscal year before current fiscal year	149	2,181
Year three, originated, two years before current fiscal year	2,160	10,396
Year four, originated, three years before current fiscal year	10,273	1,843
Year five, originated, four years before current fiscal year	1,821	752
Originated, more than five years before current fiscal year	3,790	3,117
Revolving loans	0	0
Revolving loans converted to term	0	0
Total finance receivables and loans	18,227	18,442
Consumer | Mortgage — Legacy
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	59	61
Revolving loans	137	145
Revolving loans converted to term	18	19
Total finance receivables and loans	214	225
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	1,962	1,990
Revolving loans converted to term	0	0
Total finance receivables and loans	1,962	1,990
Consumer | Credit card receivables
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	1,962	1,990
Revolving loans converted to term	0	0
Total finance receivables and loans	1,962	1,990
Consumer Portfolio Segment, Excludes Basis Adjustment for Automotive Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	8,592	31,603
Year two, originated, fiscal year before current fiscal year	28,787	27,531
Year three, originated, two years before current fiscal year	24,962	25,769
Year four, originated, three years before current fiscal year	23,844	8,398
Year five, originated, four years before current fiscal year	7,399	4,339
Originated, more than five years before current fiscal year	8,268	5,249
Revolving loans	2,099	2,135
Revolving loans converted to term	18	19
Total finance receivables and loans	103,969	105,043
Current | Consumer | Consumer automotive, excludes basis adjustment
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	8,543	30,677
Year two, originated, fiscal year before current fiscal year	27,814	23,699
Year three, originated, two years before current fiscal year	21,394	14,209
Year four, originated, three years before current fiscal year	12,627	6,132
Year five, originated, four years before current fiscal year	5,236	3,306
Originated, more than five years before current fiscal year	4,062	1,876
Revolving loans	0	0
Revolving loans converted to term	0	0
Total finance receivables and loans	79,676	79,899
Current | Consumer | Mortgage Finance
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	34	152
Year two, originated, fiscal year before current fiscal year	149	2,170
Year three, originated, two years before current fiscal year	2,148	10,374
Year four, originated, three years before current fiscal year	10,256	1,836
Year five, originated, four years before current fiscal year	1,817	747
Originated, more than five years before current fiscal year	3,747	3,073
Revolving loans	0	0
Revolving loans converted to term	0	0
Total finance receivables and loans	18,151	18,352
Current | Consumer | Mortgage — Legacy
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	50	51
Revolving loans	133	142
Revolving loans converted to term	16	17
Total finance receivables and loans	199	210
Current | Consumer | Credit card receivables
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	1,808	1,828
Revolving loans converted to term	0	0
Total finance receivables and loans	1,808	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	15	539
Year two, originated, fiscal year before current fiscal year	556	1,041
Year three, originated, two years before current fiscal year	874	739
Year four, originated, three years before current fiscal year	598	270
Year five, originated, four years before current fiscal year	218	181
Originated, more than five years before current fiscal year	226	122
Revolving loans	0	0
Revolving loans converted to term	0	0
Total finance receivables and loans	2,487	2,892
30–59 days past due | Consumer | Mortgage Finance
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	10	14
Year four, originated, three years before current fiscal year	12	3
Year five, originated, four years before current fiscal year	1	3
Originated, more than five years before current fiscal year	22	20
Revolving loans	0	0
Revolving loans converted to term	0	0
Total finance receivables and loans	45	49
30–59 days past due | Consumer | Mortgage — Legacy
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	3	3
Revolving loans	2	0
Revolving loans converted to term	0	1
Total finance receivables and loans	5	4
30–59 days past due | Consumer | Credit card receivables
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	39
Revolving loans converted to term	0	0
Total finance receivables and loans	33	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	0	170
Year two, originated, fiscal year before current fiscal year	191	443
Year three, originated, two years before current fiscal year	388	303
Year four, originated, three years before current fiscal year	247	109
Year five, originated, four years before current fiscal year	87	68
Originated, more than five years before current fiscal year	84	45
Revolving loans	0	0
Revolving loans converted to term	0	0
Total finance receivables and loans	997	1,138
60–89 days past due | Consumer | Mortgage Finance
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	1	4
Year four, originated, three years before current fiscal year	1	3
Year five, originated, four years before current fiscal year	0	0
Originated, more than five years before current fiscal year	4	5
Revolving loans	0	0
Revolving loans converted to term	0	0
Total finance receivables and loans	6	14
60–89 days past due | Consumer | Mortgage — Legacy
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		1
Revolving loans		1
Revolving loans converted to term		0
Total finance receivables and loans		2
60–89 days past due | Consumer | Credit card receivables
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	30	34
Revolving loans converted to term	0	0
Total finance receivables and loans	30	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	0	64
Year two, originated, fiscal year before current fiscal year	77	167
Year three, originated, two years before current fiscal year	146	122
Year four, originated, three years before current fiscal year	99	44
Year five, originated, four years before current fiscal year	37	32
Originated, more than five years before current fiscal year	47	28
Revolving loans	0	0
Revolving loans converted to term	0	0
Total finance receivables and loans	406	457
90 or more days past due | Consumer | Mortgage Finance
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	4
Year four, originated, three years before current fiscal year	4	1
Year five, originated, four years before current fiscal year	3	2
Originated, more than five years before current fiscal year	17	19
Revolving loans	0	0
Revolving loans converted to term	0	0
Total finance receivables and loans	25	27
90 or more days past due | Consumer | Mortgage — Legacy
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	6	6
Revolving loans	2	2
Revolving loans converted to term	2	1
Total finance receivables and loans	10	9
90 or more days past due | Consumer | Credit card receivables
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	91	89
Revolving loans converted to term	0	0
Total finance receivables and loans	$ 91	$ 89