Finance Receivables and Loans, Net Finance Receivables and Loans, Net (Commercial Criticized Exposures by Industry) (Details) - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Financing Receivable, Credit Quality Indicator [Line Items]
Finance receivables and loans, net	$ 128,231,000,000	$ 129,926,000,000
Commercial portfolio segment
Financing Receivable, Credit Quality Indicator [Line Items]
Finance receivables and loans, net	38,307,000,000	42,686,000,000
Commercial portfolio segment | Criticized
Financing Receivable, Credit Quality Indicator [Line Items]
Finance receivables and loans, net	4,227,000,000	3,976,000,000
Weighted average | Commercial portfolio segment | Criticized
Financing Receivable, Credit Quality Indicator [Line Items]
Finance receivables and loans, net	1.000	1.000
Automotive | Weighted average | Commercial portfolio segment | Criticized
Financing Receivable, Credit Quality Indicator [Line Items]
Finance receivables and loans, net	0.817	0.806
Services | Weighted average | Commercial portfolio segment | Criticized
Financing Receivable, Credit Quality Indicator [Line Items]
Finance receivables and loans, net	0.054	0.050
Electronics | Weighted average | Commercial portfolio segment | Criticized
Financing Receivable, Credit Quality Indicator [Line Items]
Finance receivables and loans, net	0.037	0.023
Other | Weighted average | Commercial portfolio segment | Criticized
Financing Receivable, Credit Quality Indicator [Line Items]
Finance receivables and loans, net	$ 0.092	$ 0.121