Finance Receivables and Loans, Net - Schedule of Financing Receivable Credit Quality Indicators Consumer (Details) - USD ($) $ in Millions	Jun. 30, 2025	Dec. 31, 2024
Financing Receivable, Credit Quality Indicator [Line Items]
Total finance receivables and loans	$ 133,229	$ 136,030
Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Total finance receivables and loans	100,953	103,285
Consumer | Consumer automotive, excludes basis adjustment
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	18,028	30,919
Year two, originated, fiscal year before current fiscal year	25,759	21,604
Year three, originated, two years before current fiscal year	17,435	16,607
Year four, originated, three years before current fiscal year	12,992	9,247
Year five, originated, four years before current fiscal year	6,827	3,344
Originated, more than five years before current fiscal year	3,332	2,077
Revolving loans	0	0
Revolving loans converted to term	0	0
Total finance receivables and loans	84,373	83,798
Consumer | Consumer mortgage finance receivables
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	0	13
Year two, originated, fiscal year before current fiscal year	20	33
Year three, originated, two years before current fiscal year	31	1,914
Year four, originated, three years before current fiscal year	1,844	9,856
Year five, originated, four years before current fiscal year	9,565	1,721
Originated, more than five years before current fiscal year	5,008	3,564
Revolving loans	105	116
Revolving loans converted to term	15	17
Total finance receivables and loans	16,588	17,234
Consumer | Other
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		2,294
Revolving loans converted to term		0
Total finance receivables and loans	0	2,294
Consumer | Automotive
Financing Receivable, Credit Quality Indicator [Line Items]
Total finance receivables and loans	84,365	83,757
Liability excluded from amortized cost of hedged asset, portfolio layer method	8	41
Consumer Portfolio Segment, Excludes Basis Adjustment for Automotive Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	18,028	30,932
Year two, originated, fiscal year before current fiscal year	25,779	21,637
Year three, originated, two years before current fiscal year	17,466	18,521
Year four, originated, three years before current fiscal year	14,836	19,103
Year five, originated, four years before current fiscal year	16,392	5,065
Originated, more than five years before current fiscal year	8,340	5,641
Revolving loans	105	2,410
Revolving loans converted to term	15	17
Total finance receivables and loans	100,961	103,326
Current | Consumer | Consumer automotive, excludes basis adjustment
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	17,883	30,322
Year two, originated, fiscal year before current fiscal year	24,943	20,387
Year three, originated, two years before current fiscal year	16,358	15,234
Year four, originated, three years before current fiscal year	11,895	8,368
Year five, originated, four years before current fiscal year	6,171	3,064
Originated, more than five years before current fiscal year	3,010	1,849
Revolving loans	0	0
Revolving loans converted to term	0	0
Total finance receivables and loans	80,260	79,224
Current | Consumer | Consumer mortgage finance receivables
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	0	13
Year two, originated, fiscal year before current fiscal year	20	31
Year three, originated, two years before current fiscal year	31	1,901
Year four, originated, three years before current fiscal year	1,827	9,834
Year five, originated, four years before current fiscal year	9,535	1,714
Originated, more than five years before current fiscal year	4,948	3,503
Revolving loans	103	115
Revolving loans converted to term	14	15
Total finance receivables and loans	16,478	17,126
Current | Consumer | Other
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		2,140
Revolving loans converted to term		0
Total finance receivables and loans		2,140
30–59 days past due | Consumer | Consumer automotive, excludes basis adjustment
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	112	419
Year two, originated, fiscal year before current fiscal year	541	756
Year three, originated, two years before current fiscal year	664	841
Year four, originated, three years before current fiscal year	671	546
Year five, originated, four years before current fiscal year	415	174
Originated, more than five years before current fiscal year	198	141
Revolving loans	0	0
Revolving loans converted to term	0	0
Total finance receivables and loans	2,601	2,877
30–59 days past due | Consumer | Consumer mortgage finance 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	7
Year four, originated, three years before current fiscal year	8	9
Year five, originated, four years before current fiscal year	11	5
Originated, more than five years before current fiscal year	24	27
Revolving loans	0	0
Revolving loans converted to term	0	0
Total finance receivables and loans	43	48
30–59 days past due | Consumer | Other
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		35
Revolving loans converted to term		0
Total finance receivables and loans		35
60–89 days past due | Consumer | Consumer automotive, excludes basis adjustment
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	27	131
Year two, originated, fiscal year before current fiscal year	199	338
Year three, originated, two years before current fiscal year	307	390
Year four, originated, three years before current fiscal year	318	240
Year five, originated, four years before current fiscal year	171	75
Originated, more than five years before current fiscal year	82	56
Revolving loans	0	0
Revolving loans converted to term	0	0
Total finance receivables and loans	1,104	1,230
60–89 days past due | Consumer | Consumer mortgage finance 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	4
Year four, originated, three years before current fiscal year	3	4
Year five, originated, four years before current fiscal year	2	1
Originated, more than five years before current fiscal year	5	4
Revolving loans	1	0
Revolving loans converted to term	0	0
Total finance receivables and loans	11	13
60–89 days past due | Consumer | Other
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		33
Revolving loans converted to term		0
Total finance receivables and loans		33
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	6	47
Year two, originated, fiscal year before current fiscal year	76	123
Year three, originated, two years before current fiscal year	106	142
Year four, originated, three years before current fiscal year	108	93
Year five, originated, four years before current fiscal year	70	31
Originated, more than five years before current fiscal year	42	31
Revolving loans	0	0
Revolving loans converted to term	0	0
Total finance receivables and loans	408	467
90 or more days past due | Consumer | Consumer mortgage finance 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	2
Year three, originated, two years before current fiscal year	0	2
Year four, originated, three years before current fiscal year	6	9
Year five, originated, four years before current fiscal year	17	1
Originated, more than five years before current fiscal year	31	30
Revolving loans	1	1
Revolving loans converted to term	1	2
Total finance receivables and loans	$ 56	47
90 or more days past due | Consumer | Other
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		86
Revolving loans converted to term		0
Total finance receivables and loans		$ 86