Finance Receivables and Loans, Net - Schedule of Financing Receivables, Nonaccrual Status (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023	Dec. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, recorded investment, nonaccrual status	$ 1,215		$ 1,215		$ 1,252	$ 1,394	$ 1,384	$ 1,454
Financing receivable, nonaccrual, with no allowance	534		534			585
Financing receivable, nonaccrual, interest income	5	$ 4	10	$ 7
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, recorded investment, nonaccrual status	1,099		1,099		1,149	1,275	1,225	1,292
Financing receivable, nonaccrual, with no allowance	523		523			564
Consumer | Automotive
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, recorded investment, nonaccrual status	978		978		1,010	1,129	1,110	1,187
Financing receivable, nonaccrual, with no allowance	492		492			531
Consumer | Consumer mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, recorded investment, nonaccrual status	41		41		45	54	49	49
Financing receivable, nonaccrual, with no allowance	31		31			33
Consumer | Mortgage Finance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, recorded investment, nonaccrual status	32		32		33	41	34	34
Financing receivable, nonaccrual, with no allowance	22		22			21
Consumer | Mortgage — Legacy
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, recorded investment, nonaccrual status	9		9		12	13	15	15
Financing receivable, nonaccrual, with no allowance	9		9			12
Consumer | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, recorded investment, nonaccrual status	80		80		94	92	66	56
Financing receivable, nonaccrual, with no allowance	0		0			0
Consumer | Personal Lending
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, recorded investment, nonaccrual status						0	12	13
Financing receivable, nonaccrual, with no allowance						0
Consumer | Credit Card
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, recorded investment, nonaccrual status	80		80		94	92	54	43
Financing receivable, nonaccrual, with no allowance	0		0			0
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, recorded investment, nonaccrual status	116		116		103	119	159	162
Financing receivable, nonaccrual, with no allowance	11		11			21
Commercial | Automotive
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, recorded investment, nonaccrual status	18		18		5	18	0	5
Financing receivable, nonaccrual, with no allowance	5		5			13
Commercial | Consumer mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, recorded investment, nonaccrual status	2		2		1	3	0	0
Financing receivable, nonaccrual, with no allowance	2		2			3
Commercial | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, recorded investment, nonaccrual status	96		96		$ 97	98	$ 159	$ 157
Financing receivable, nonaccrual, with no allowance	$ 4		$ 4			$ 5