Finance Receivables And Loans, Net (Financing Receivable Credit Quality Indicators - Performing and Nonperforming) (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	$ 110,876	$ 111,600	$ 99,856
Consumer Portfolio Segment [Member] | Consumer Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	73,688	74,065
Consumer Portfolio Segment [Member] | Consumer Loan [Member] | Performing Financial Instruments [Member]
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	73,080	73,462
Consumer Portfolio Segment [Member] | Consumer Loan [Member] | Nonperforming Financial Instruments [Member]
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	608	603
Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	63,013	64,292	57,447
Consumer Portfolio Segment [Member] | Automobile Loan [Member] | Performing Financial Instruments [Member]
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	62,521	63,817
Consumer Portfolio Segment [Member] | Automobile Loan [Member] | Nonperforming Financial Instruments [Member]
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	492	475
Consumer Portfolio Segment [Member] | Residential Mortgage [Member]
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	10,675	9,773	$ 7,652
Consumer Portfolio Segment [Member] | Residential Mortgage [Member] | Performing Financial Instruments [Member]
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	10,559	9,645
Consumer Portfolio Segment [Member] | Residential Mortgage [Member] | Nonperforming Financial Instruments [Member]
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	116	128
Consumer Portfolio Segment [Member] | Mortgage Finance [Member]
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	7,443	6,413
Consumer Portfolio Segment [Member] | Mortgage Finance [Member] | Performing Financial Instruments [Member]
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	7,432	6,398
Consumer Portfolio Segment [Member] | Mortgage Finance [Member] | Nonperforming Financial Instruments [Member]
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	11	15
Consumer Portfolio Segment [Member] | Mortgage - Legacy [Member]
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	3,232	3,360
Consumer Portfolio Segment [Member] | Mortgage - Legacy [Member] | Performing Financial Instruments [Member]
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	3,127	3,247
Consumer Portfolio Segment [Member] | Mortgage - Legacy [Member] | Nonperforming Financial Instruments [Member]
Financing Receivable, Recorded Investment [Line Items]
Finance receivables and loans, net	$ 105	$ 113