Finance Receivables and Loans, Net - Schedule of Loan Modifications (Details) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2024 USD ($)	Jun. 30, 2023 USD ($) loan	Jun. 30, 2024 USD ($)	Jun. 30, 2023 USD ($) loan	Jun. 30, 2024 USD ($) loan	Dec. 31, 2023 USD ($)
Financing Receivable, Troubled Debt Restructuring
Trial modifications, term			3 months
Trial modifications, amount	$ 1		$ 1		$ 1	$ 5
Total	116	$ 113	$ 323	$ 205
Percentage of total			0.20%	0.10%
Payment deferrals
Financing Receivable, Troubled Debt Restructuring
Total	11	36	$ 11	$ 64
Contractual maturity extensions
Financing Receivable, Troubled Debt Restructuring
Total	98	61	299	86
Principal forgiveness
Financing Receivable, Troubled Debt Restructuring
Total	2	12	4	14
Interest rate concessions
Financing Receivable, Troubled Debt Restructuring
Total	5	3	9	6
Combination
Financing Receivable, Troubled Debt Restructuring
Total	0	1	0	35
Consumer
Financing Receivable, Troubled Debt Restructuring
Total	105	41	204	98	382
Consumer | Current
Financing Receivable, Troubled Debt Restructuring
Total		36		85	293
Consumer | 30–59 days past due
Financing Receivable, Troubled Debt Restructuring
Total		3		6	57
Consumer | 60–89 days past due
Financing Receivable, Troubled Debt Restructuring
Total		0		3	20
Consumer | 90 or more days past due
Financing Receivable, Troubled Debt Restructuring
Total		2		4	12
Consumer | Payment deferrals
Financing Receivable, Troubled Debt Restructuring
Total	0	0	0	0
Consumer | Contractual maturity extensions
Financing Receivable, Troubled Debt Restructuring
Total	98	25	191	43
Consumer | Principal forgiveness
Financing Receivable, Troubled Debt Restructuring
Total	2	12	4	14
Consumer | Interest rate concessions
Financing Receivable, Troubled Debt Restructuring
Total	5	3	9	6
Consumer | Combination
Financing Receivable, Troubled Debt Restructuring
Total	0	1	0	35
Consumer | Automotive
Financing Receivable, Troubled Debt Restructuring
Total	99	$ 37	193	$ 87	$ 365
Number of loans redefaulted | loan		29		41	787
Amortized cost of loans redefaulted		$ 1		$ 1	$ 18
Consumer | Automotive | Current
Financing Receivable, Troubled Debt Restructuring
Total		34		79	281
Consumer | Automotive | 30–59 days past due
Financing Receivable, Troubled Debt Restructuring
Total		2		5	56
Consumer | Automotive | 60–89 days past due
Financing Receivable, Troubled Debt Restructuring
Total		0		0	19
Consumer | Automotive | 90 or more days past due
Financing Receivable, Troubled Debt Restructuring
Total		1		3	9
Consumer | Automotive | Payment deferrals
Financing Receivable, Troubled Debt Restructuring
Total	$ 0	$ 0	$ 0	$ 0
Number of months extended/deferred	29 months	26 months	29 months	25 months
Consumer | Automotive | Contractual maturity extensions
Financing Receivable, Troubled Debt Restructuring
Total	$ 97	$ 25	$ 190	$ 40	359
Consumer | Automotive | Contractual maturity extensions | Current
Financing Receivable, Troubled Debt Restructuring
Total		24		38	280
Consumer | Automotive | Contractual maturity extensions | 30–59 days past due
Financing Receivable, Troubled Debt Restructuring
Total		1		2	56
Consumer | Automotive | Contractual maturity extensions | 60–89 days past due
Financing Receivable, Troubled Debt Restructuring
Total		0		0	19
Consumer | Automotive | Contractual maturity extensions | 90 or more days past due
Financing Receivable, Troubled Debt Restructuring
Total		0		0	4
Consumer | Automotive | Principal forgiveness
Financing Receivable, Troubled Debt Restructuring
Total	2	12	3	14	5
Principal forgiveness, amount forgiven	1	2	1	2
Consumer | Automotive | Principal forgiveness | Current
Financing Receivable, Troubled Debt Restructuring
Total		10		10	0
Consumer | Automotive | Principal forgiveness | 30–59 days past due
Financing Receivable, Troubled Debt Restructuring
Total		1		1	0
Consumer | Automotive | Principal forgiveness | 60–89 days past due
Financing Receivable, Troubled Debt Restructuring
Total		0		0	0
Consumer | Automotive | Principal forgiveness | 90 or more days past due
Financing Receivable, Troubled Debt Restructuring
Total		1		3	5
Consumer | Automotive | Interest rate concessions
Financing Receivable, Troubled Debt Restructuring
Total	$ 0	$ 0	$ 0	$ 0
Interest rate concessions, initial rate	0.00%	0.00%	0.00%	0.00%
Interest rate concessions, revised rate	0.00%	0.00%	0.00%	0.00%
Consumer | Automotive | Combination
Financing Receivable, Troubled Debt Restructuring
Total	$ 0	$ 0	$ 0	$ 33	1
Interest rate concessions, initial rate	0.00%	0.00%	0.00%	10.40%
Interest rate concessions, revised rate	0.00%	0.00%	0.00%	9.80%
Payment extensions, initial term				75 months
Payment extensions, revised term				85 months
Consumer | Automotive | Combination | Current
Financing Receivable, Troubled Debt Restructuring
Total				$ 31	1
Consumer | Automotive | Combination | 30–59 days past due
Financing Receivable, Troubled Debt Restructuring
Total				2	0
Consumer | Automotive | Combination | 60–89 days past due
Financing Receivable, Troubled Debt Restructuring
Total				0	0
Consumer | Automotive | Combination | 90 or more days past due
Financing Receivable, Troubled Debt Restructuring
Total				0	0
Consumer | Consumer mortgage
Financing Receivable, Troubled Debt Restructuring
Total	$ 1	$ 1	$ 1	5	3
Consumer | Consumer mortgage | Current
Financing Receivable, Troubled Debt Restructuring
Total		1		3	3
Consumer | Consumer mortgage | 30–59 days past due
Financing Receivable, Troubled Debt Restructuring
Total		0		0	0
Consumer | Consumer mortgage | 60–89 days past due
Financing Receivable, Troubled Debt Restructuring
Total		0		2	0
Consumer | Consumer mortgage | 90 or more days past due
Financing Receivable, Troubled Debt Restructuring
Total		0		0	0
Consumer | Consumer mortgage | Payment deferrals
Financing Receivable, Troubled Debt Restructuring
Total	$ 0	0	$ 0	$ 0
Number of months extended/deferred	224 months		223 months	146 months
Consumer | Consumer mortgage | Contractual maturity extensions
Financing Receivable, Troubled Debt Restructuring
Total	$ 1	0	$ 1	$ 3
Consumer | Consumer mortgage | Principal forgiveness
Financing Receivable, Troubled Debt Restructuring
Total	0	0	0	0
Principal forgiveness, amount forgiven	0	0	0	0
Consumer | Consumer mortgage | Interest rate concessions
Financing Receivable, Troubled Debt Restructuring
Total	$ 0	$ 0	$ 0	$ 0
Interest rate concessions, initial rate	0.00%	0.00%	0.00%	0.00%
Interest rate concessions, revised rate	0.00%	0.00%	0.00%	0.00%
Consumer | Consumer mortgage | Combination
Financing Receivable, Troubled Debt Restructuring
Total	$ 0	$ 1	$ 0	$ 2
Interest rate concessions, initial rate	0.00%	4.00%	0.00%	4.60%
Interest rate concessions, revised rate	0.00%	2.00%	0.00%	3.40%
Payment extensions, initial term		294 months		309 months
Payment extensions, revised term		480 months		470 months
Consumer | Mortgage Finance
Financing Receivable, Troubled Debt Restructuring
Total	$ 1	$ 1	$ 1	$ 4	2
Consumer | Mortgage Finance | Current
Financing Receivable, Troubled Debt Restructuring
Total		1		2	2
Consumer | Mortgage Finance | 30–59 days past due
Financing Receivable, Troubled Debt Restructuring
Total		0		0	0
Consumer | Mortgage Finance | 60–89 days past due
Financing Receivable, Troubled Debt Restructuring
Total		0		2	0
Consumer | Mortgage Finance | 90 or more days past due
Financing Receivable, Troubled Debt Restructuring
Total		0		0	0
Consumer | Mortgage Finance | Payment deferrals
Financing Receivable, Troubled Debt Restructuring
Total	$ 0	0	$ 0	$ 0
Number of months extended/deferred	224 months		223 months	174 months
Consumer | Mortgage Finance | Contractual maturity extensions
Financing Receivable, Troubled Debt Restructuring
Total	$ 1	0	$ 1	$ 2	2
Consumer | Mortgage Finance | Contractual maturity extensions | Current
Financing Receivable, Troubled Debt Restructuring
Total				2	2
Consumer | Mortgage Finance | Contractual maturity extensions | 30–59 days past due
Financing Receivable, Troubled Debt Restructuring
Total				0	0
Consumer | Mortgage Finance | Contractual maturity extensions | 60–89 days past due
Financing Receivable, Troubled Debt Restructuring
Total				0	0
Consumer | Mortgage Finance | Contractual maturity extensions | 90 or more days past due
Financing Receivable, Troubled Debt Restructuring
Total				0	0
Consumer | Mortgage Finance | Principal forgiveness
Financing Receivable, Troubled Debt Restructuring
Total	0	0	0	0
Principal forgiveness, amount forgiven	0	0	0	0
Consumer | Mortgage Finance | Interest rate concessions
Financing Receivable, Troubled Debt Restructuring
Total	$ 0	$ 0	$ 0	$ 0
Interest rate concessions, initial rate	0.00%	0.00%	0.00%	0.00%
Interest rate concessions, revised rate	0.00%	0.00%	0.00%	0.00%
Consumer | Mortgage Finance | Combination
Financing Receivable, Troubled Debt Restructuring
Total	$ 0	$ 1	$ 0	$ 2
Number of months extended/deferred		186 months		186 months
Interest rate concessions, initial rate	0.00%	4.00%	0.00%	4.60%
Interest rate concessions, revised rate	0.00%	2.00%	0.00%	3.40%
Payment extensions, initial term		294 months		309 months
Payment extensions, revised term		480 months		470 months
Consumer | Mortgage Finance | Combination | Current
Financing Receivable, Troubled Debt Restructuring
Total		$ 1		$ 0
Consumer | Mortgage Finance | Combination | 30–59 days past due
Financing Receivable, Troubled Debt Restructuring
Total		0		0
Consumer | Mortgage Finance | Combination | 60–89 days past due
Financing Receivable, Troubled Debt Restructuring
Total		0		2
Consumer | Mortgage Finance | Combination | 90 or more days past due
Financing Receivable, Troubled Debt Restructuring
Total		0		0
Consumer | Mortgage — Legacy
Financing Receivable, Troubled Debt Restructuring
Total				1	1
Consumer | Mortgage — Legacy | Current
Financing Receivable, Troubled Debt Restructuring
Total				1	1
Consumer | Mortgage — Legacy | 30–59 days past due
Financing Receivable, Troubled Debt Restructuring
Total				0	0
Consumer | Mortgage — Legacy | 60–89 days past due
Financing Receivable, Troubled Debt Restructuring
Total				0	0
Consumer | Mortgage — Legacy | 90 or more days past due
Financing Receivable, Troubled Debt Restructuring
Total				0	0
Consumer | Mortgage — Legacy | Payment deferrals
Financing Receivable, Troubled Debt Restructuring
Total				$ 0
Number of months extended/deferred				96 months
Consumer | Mortgage — Legacy | Contractual maturity extensions
Financing Receivable, Troubled Debt Restructuring
Total				$ 1
Consumer | Mortgage — Legacy | Contractual maturity extensions | Current
Financing Receivable, Troubled Debt Restructuring
Total				1
Consumer | Mortgage — Legacy | Contractual maturity extensions | 30–59 days past due
Financing Receivable, Troubled Debt Restructuring
Total				0
Consumer | Mortgage — Legacy | Contractual maturity extensions | 60–89 days past due
Financing Receivable, Troubled Debt Restructuring
Total				0
Consumer | Mortgage — Legacy | Contractual maturity extensions | 90 or more days past due
Financing Receivable, Troubled Debt Restructuring
Total				0
Consumer | Mortgage — Legacy | Principal forgiveness
Financing Receivable, Troubled Debt Restructuring
Total				0
Principal forgiveness, amount forgiven				0
Consumer | Mortgage — Legacy | Interest rate concessions
Financing Receivable, Troubled Debt Restructuring
Total				$ 0
Interest rate concessions, initial rate				0.00%
Interest rate concessions, revised rate				0.00%
Consumer | Mortgage — Legacy | Combination
Financing Receivable, Troubled Debt Restructuring
Total				$ 0	1
Interest rate concessions, initial rate				0.00%
Interest rate concessions, revised rate				0.00%
Consumer | Mortgage — Legacy | Combination | Current
Financing Receivable, Troubled Debt Restructuring
Total					1
Consumer | Mortgage — Legacy | Combination | 30–59 days past due
Financing Receivable, Troubled Debt Restructuring
Total					0
Consumer | Mortgage — Legacy | Combination | 60–89 days past due
Financing Receivable, Troubled Debt Restructuring
Total					0
Consumer | Mortgage — Legacy | Combination | 90 or more days past due
Financing Receivable, Troubled Debt Restructuring
Total					0
Consumer | Other
Financing Receivable, Troubled Debt Restructuring
Total	$ 5	3	$ 10	$ 6	14
Consumer | Other | Current
Financing Receivable, Troubled Debt Restructuring
Total		1		3	9
Consumer | Other | 30–59 days past due
Financing Receivable, Troubled Debt Restructuring
Total		1		1	1
Consumer | Other | 60–89 days past due
Financing Receivable, Troubled Debt Restructuring
Total		0		1	1
Consumer | Other | 90 or more days past due
Financing Receivable, Troubled Debt Restructuring
Total		1		1	3
Consumer | Other | Payment deferrals
Financing Receivable, Troubled Debt Restructuring
Total	0	0	0	0
Consumer | Other | Contractual maturity extensions
Financing Receivable, Troubled Debt Restructuring
Total	0	0	0	0
Consumer | Other | Principal forgiveness
Financing Receivable, Troubled Debt Restructuring
Total	0	0	1	0
Principal forgiveness, amount forgiven	0	0	1	0
Consumer | Other | Interest rate concessions
Financing Receivable, Troubled Debt Restructuring
Total	$ 5	$ 3	$ 9	$ 6
Interest rate concessions, initial rate	30.40%	30.30%	30.40%	30.00%
Interest rate concessions, revised rate	9.80%	10.90%	8.00%	9.00%
Consumer | Other | Combination
Financing Receivable, Troubled Debt Restructuring
Total	$ 0	$ 0	$ 0	$ 0
Interest rate concessions, initial rate	0.00%	0.00%	0.00%	0.00%
Interest rate concessions, revised rate	0.00%	0.00%	0.00%	0.00%
Consumer | Credit Card
Financing Receivable, Troubled Debt Restructuring
Total	$ 5	$ 3	$ 10	$ 6
Consumer | Credit Card | Payment deferrals
Financing Receivable, Troubled Debt Restructuring
Total	0	0	0	0
Consumer | Credit Card | Contractual maturity extensions
Financing Receivable, Troubled Debt Restructuring
Total	0	0	0	0
Consumer | Credit Card | Principal forgiveness
Financing Receivable, Troubled Debt Restructuring
Total	0	0	1	0
Principal forgiveness, amount forgiven	0	0	1	0
Consumer | Credit Card | Interest rate concessions
Financing Receivable, Troubled Debt Restructuring
Total	$ 5	$ 3	$ 9	$ 6	14
Interest rate concessions, initial rate	30.40%	30.30%	30.40%	30.00%
Interest rate concessions, revised rate	9.80%	10.90%	8.00%	9.00%
Consumer | Credit Card | Interest rate concessions | Current
Financing Receivable, Troubled Debt Restructuring
Total		$ 1		$ 3	9
Consumer | Credit Card | Interest rate concessions | 30–59 days past due
Financing Receivable, Troubled Debt Restructuring
Total		1		1	1
Consumer | Credit Card | Interest rate concessions | 60–89 days past due
Financing Receivable, Troubled Debt Restructuring
Total		0		1	1
Consumer | Credit Card | Interest rate concessions | 90 or more days past due
Financing Receivable, Troubled Debt Restructuring
Total		1		1	3
Consumer | Credit Card | Combination
Financing Receivable, Troubled Debt Restructuring
Total	$ 0	$ 0	$ 0	$ 0
Interest rate concessions, initial rate	0.00%	0.00%	0.00%	0.00%
Interest rate concessions, revised rate	0.00%	0.00%	0.00%	0.00%
Commercial
Financing Receivable, Troubled Debt Restructuring
Total	$ 11	$ 72	$ 119	$ 107	119
Commercial | Pass
Financing Receivable, Troubled Debt Restructuring
Total		31		31	53
Commercial | Special mention
Financing Receivable, Troubled Debt Restructuring
Total		0		7	0
Commercial | Substandard
Financing Receivable, Troubled Debt Restructuring
Total		41		41	66
Commercial | Doubtful
Financing Receivable, Troubled Debt Restructuring
Total		0		28	0
Commercial | Payment deferrals
Financing Receivable, Troubled Debt Restructuring
Total	$ 11	$ 36	$ 11	$ 64
Number of months extended/deferred	7 months	6 months	39 months	12 months
Commercial | Contractual maturity extensions
Financing Receivable, Troubled Debt Restructuring
Total	$ 0	$ 36	$ 108	$ 43
Commercial | Principal forgiveness
Financing Receivable, Troubled Debt Restructuring
Total	0	0	0	0
Principal forgiveness, amount forgiven	0	0	0	0
Commercial | Interest rate concessions
Financing Receivable, Troubled Debt Restructuring
Total	$ 0	$ 0	$ 0	$ 0
Interest rate concessions, initial rate	0.00%	0.00%	0.00%	0.00%
Interest rate concessions, revised rate	0.00%	0.00%	0.00%	0.00%
Commercial | Combination
Financing Receivable, Troubled Debt Restructuring
Total	$ 0	$ 0	$ 0	$ 0
Interest rate concessions, initial rate	0.00%	0.00%	0.00%	0.00%
Interest rate concessions, revised rate	0.00%	0.00%	0.00%	0.00%
Commercial | Automotive
Financing Receivable, Troubled Debt Restructuring
Total	$ 11		$ 11
Commercial | Automotive | Payment deferrals
Financing Receivable, Troubled Debt Restructuring
Total	$ 11		$ 11		11
Number of months extended/deferred	7 months		7 months
Commercial | Automotive | Payment deferrals | Pass
Financing Receivable, Troubled Debt Restructuring
Total					0
Commercial | Automotive | Payment deferrals | Special mention
Financing Receivable, Troubled Debt Restructuring
Total					0
Commercial | Automotive | Payment deferrals | Substandard
Financing Receivable, Troubled Debt Restructuring
Total					11
Commercial | Automotive | Payment deferrals | Doubtful
Financing Receivable, Troubled Debt Restructuring
Total					0
Commercial | Automotive | Contractual maturity extensions
Financing Receivable, Troubled Debt Restructuring
Total	$ 0		$ 0
Commercial | Automotive | Principal forgiveness
Financing Receivable, Troubled Debt Restructuring
Total	0		0
Principal forgiveness, amount forgiven	0		0
Commercial | Automotive | Interest rate concessions
Financing Receivable, Troubled Debt Restructuring
Total	$ 0		$ 0
Interest rate concessions, initial rate	0.00%		0.00%
Interest rate concessions, revised rate	0.00%		0.00%
Commercial | Automotive | Combination
Financing Receivable, Troubled Debt Restructuring
Total	$ 0		$ 0
Interest rate concessions, initial rate	0.00%		0.00%
Interest rate concessions, revised rate	0.00%		0.00%
Commercial | Other
Financing Receivable, Troubled Debt Restructuring
Total		$ 72	$ 108	$ 107
Commercial | Other | Payment deferrals
Financing Receivable, Troubled Debt Restructuring
Total		$ 36	$ 0	$ 64
Number of months extended/deferred		6 months	42 months	12 months
Commercial | Other | Payment deferrals | Pass
Financing Receivable, Troubled Debt Restructuring
Total		$ 0		$ 0
Commercial | Other | Payment deferrals | Special mention
Financing Receivable, Troubled Debt Restructuring
Total		0		0
Commercial | Other | Payment deferrals | Substandard
Financing Receivable, Troubled Debt Restructuring
Total		36		36
Commercial | Other | Payment deferrals | Doubtful
Financing Receivable, Troubled Debt Restructuring
Total		0		28
Commercial | Other | Contractual maturity extensions
Financing Receivable, Troubled Debt Restructuring
Total		36	$ 108	43	108
Commercial | Other | Contractual maturity extensions | Pass
Financing Receivable, Troubled Debt Restructuring
Total		31		31	53
Commercial | Other | Contractual maturity extensions | Special mention
Financing Receivable, Troubled Debt Restructuring
Total		0		7	0
Commercial | Other | Contractual maturity extensions | Substandard
Financing Receivable, Troubled Debt Restructuring
Total		5		5	55
Commercial | Other | Contractual maturity extensions | Doubtful
Financing Receivable, Troubled Debt Restructuring
Total		0		0	$ 0
Commercial | Other | Principal forgiveness
Financing Receivable, Troubled Debt Restructuring
Total		0	0	0
Principal forgiveness, amount forgiven		0	0	0
Commercial | Other | Interest rate concessions
Financing Receivable, Troubled Debt Restructuring
Total		$ 0	$ 0	$ 0
Interest rate concessions, initial rate		0.00%	0.00%	0.00%
Interest rate concessions, revised rate		0.00%	0.00%	0.00%
Commercial | Other | Combination
Financing Receivable, Troubled Debt Restructuring
Total		$ 0	$ 0	$ 0
Interest rate concessions, initial rate		0.00%	0.00%	0.00%
Interest rate concessions, revised rate		0.00%	0.00%	0.00%