Finance Receivables and Loans, Net (Commercial criticized risk exposure) (Details) - Commercial portfolio segment	Dec. 31, 2020	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost, finance receivables and loans, percentage	100.00%	100.00%
Automotive
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost, finance receivables and loans, percentage	67.70%	81.70%
Health/medical
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost, finance receivables and loans, percentage	7.30%	2.90%
Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost, finance receivables and loans, percentage	5.80%	5.40%
Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost, finance receivables and loans, percentage	19.20%	10.00%