Finance Receivables And Loans, Net (Financing Receivable Credit Quality Indicators) (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014	Sep. 30, 2014
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	$ 107,991	$ 99,948
Loans and Leases Receivable, Gross, Excluding Fair Value Option Election	107,990	99,947	$ 99,517
Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	63,610	56,570
Loans and Leases Receivable, Gross, Excluding Fair Value Option Election	63,610		58,675
Consumer Portfolio Segment [Member] | Automobile Loan [Member] | Performing Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	63,197	56,184
Consumer Portfolio Segment [Member] | Automobile Loan [Member] | Nonperforming Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	413	386
Consumer Portfolio Segment [Member] | Residential Mortgage [Member]
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	9,770	7,474
Loans and Leases Receivable, Gross, Excluding Fair Value Option Election	9,769	7,473	$ 7,594
Consumer Portfolio Segment [Member] | Residential Mortgage [Member] | Performing Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	9,620	7,296
Consumer Portfolio Segment [Member] | Residential Mortgage [Member] | Nonperforming Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	$ 149	$ 177