Finance Receivables and Loans, Net (Credit Quality Indicators - Macroeconomic Impacts) (Details) - Consumer portfolio segment	Sep. 30, 2020	Jun. 30, 2020
Operating Segments | Automotive Finance operations
Financing Receivable, Credit Quality Indicator [Line Items]
Customers enrolled in loan program	1,200,000
Percentage of customers to reach scheduled expiration of deferral program	99.00%
Percentage of customers, exited loan deferral program and remain outstanding, current	92.00%
Percentage of customers, exited loan deferral program and remain outstanding, 30+ days paste due	8.00%
Operating Segments | Mortgage Finance operations
Financing Receivable, Credit Quality Indicator [Line Items]
Customers enrolled in loan program	2,350
Percentage of customers, exited loan deferral program and remain outstanding, current	8700.00%
Percentage of customers, exited loan deferral program and remain outstanding, 30+ days paste due	13.00%
Percentage of mortgage customers who enrolled in deferral program	7.00%
Cancelled deferrals ahead of schedule or balance paid in full	40.00%
Customers active in forbearance	30.00%
Customers exited pandemic-relief program	3000.00%
Corporate and Other
Financing Receivable, Credit Quality Indicator [Line Items]
Customers enrolled in loan program		6,300
Customers exited pandemic-relief program	8400.00%
Percent of customers electing deferral considered current at time of enrollment		84.00%