Finance Receivables and Loans, Net (Concentration Risk) (Details) - Consumer - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
California | Financing Receivable | Geographic Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percentage	26.40%
Texas | Financing Receivable | Geographic Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percentage		26.50%
Automotive | Financing Receivable | Geographic Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percentage	100.00%	100.00%
Automotive | California | Financing Receivable | Geographic Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percentage	8.50%	8.70%
Automotive | Texas | Financing Receivable | Geographic Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percentage	13.70%	13.60%
Automotive | Florida | Financing Receivable | Geographic Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percentage	9.50%	9.50%
Automotive | Pennsylvania | Financing Receivable | Geographic Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percentage	4.50%	4.50%
Automotive | Georgia | Financing Receivable | Geographic Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percentage	4.10%	4.10%
Automotive | North Carolina | Financing Receivable | Geographic Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percentage	4.30%	4.10%
Automotive | New York | Financing Receivable | Geographic Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percentage	3.70%	3.60%
Automotive | Illinois | Financing Receivable | Geographic Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percentage	3.30%	3.50%
Automotive | New Jersey | Financing Receivable | Geographic Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percentage	3.20%	3.20%
Automotive | Ohio | Financing Receivable | Geographic Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percentage	3.40%	3.40%
Automotive | Other United States | Financing Receivable | Geographic Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percentage	41.80%	41.80%
Mortgage Finance | Financing Receivable | Geographic Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percentage	100.00%	100.00%
Mortgage Finance | California | Financing Receivable | Geographic Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percentage	39.20%	38.80%
Mortgage Finance | Texas | Financing Receivable | Geographic Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percentage	7.30%	7.30%
Mortgage Finance | Florida | Financing Receivable | Geographic Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percentage	6.50%	6.60%
Mortgage Finance | Pennsylvania | Financing Receivable | Geographic Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percentage	2.10%	2.10%
Mortgage Finance | Georgia | Financing Receivable | Geographic Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percentage	2.90%	2.90%
Mortgage Finance | North Carolina | Financing Receivable | Geographic Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percentage	1.90%	1.90%
Mortgage Finance | New York | Financing Receivable | Geographic Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percentage	1.90%	1.90%
Mortgage Finance | Illinois | Financing Receivable | Geographic Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percentage	2.80%	2.80%
Mortgage Finance | New Jersey | Financing Receivable | Geographic Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percentage	2.40%	2.40%
Mortgage Finance | Ohio | Financing Receivable | Geographic Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percentage	0.40%	0.40%
Mortgage Finance | Other United States | Financing Receivable | Geographic Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percentage	32.60%	32.90%
Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Fair value, option, carrying amount, financing receivable, no allowance		$ 3	$ 7
Other | Financing Receivable | Geographic Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percentage	100.00%	100.00%
Other | California | Financing Receivable | Geographic Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percentage	9.40%	8.40%
Other | Texas | Financing Receivable | Geographic Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percentage	7.60%	7.70%
Other | Florida | Financing Receivable | Geographic Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percentage	9.00%	7.80%
Other | Pennsylvania | Financing Receivable | Geographic Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percentage	4.20%	4.60%
Other | Georgia | Financing Receivable | Geographic Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percentage	3.70%	3.50%
Other | North Carolina | Financing Receivable | Geographic Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percentage	2.90%	4.60%
Other | New York | Financing Receivable | Geographic Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percentage	5.40%	4.80%
Other | Illinois | Financing Receivable | Geographic Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percentage	4.60%	4.30%
Other | New Jersey | Financing Receivable | Geographic Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percentage	3.70%	3.60%
Other | Ohio | Financing Receivable | Geographic Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percentage	4.50%	3.60%
Other | Other United States | Financing Receivable | Geographic Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percentage	45.00%	47.10%