Finance Receivables And Loans, Net (Financing Receivable Credit Quality Indicators) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	$ 111,600	$ 99,948
Loans and Leases Receivable, Gross, Excluding Fair Value Option Election	111,600	99,947
Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	64,292	56,570
Loans and Leases Receivable, Gross, Excluding Fair Value Option Election		56,570
Consumer Portfolio Segment [Member] | Automobile Loan [Member] | Performing Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	63,817	56,184
Consumer Portfolio Segment [Member] | Automobile Loan [Member] | Nonperforming Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	475	386
Consumer Portfolio Segment [Member] | Residential Mortgage [Member]
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	9,773	7,474
Loans and Leases Receivable, Gross, Excluding Fair Value Option Election		7,473
Consumer Portfolio Segment [Member] | Residential Mortgage [Member] | Performing Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	9,645	7,296
Consumer Portfolio Segment [Member] | Residential Mortgage [Member] | Nonperforming Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	$ 128	$ 177