Finance Receivables And Loans, Net (Past Due Financing Receivables And Loans) (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014	Sep. 30, 2014
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	$ 2,143	$ 2,031
Current	105,847	97,916
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, Past Due [Line Items]
Total past due	1,929	1,797
Current	61,681	54,773
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] | Residential Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	208	225
Current	9,561	7,248
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
Commercial Portfolio Segment [Member] | Commercial Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	6	9
Current	34,605	35,895
Finance receivables and loans, net	34,611	35,904
Loans and Leases Receivable, Gross, Excluding Fair Value Option Election	34,611		$ 33,248
Commercial Portfolio Segment [Member] | Commercial And Industrial Automobile [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	6	9
Current	29,014	30,862
Finance receivables and loans, net	29,020	30,871
Commercial Portfolio Segment [Member] | Commercial And Industrial Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0	0
Current	2,289	1,882
Finance receivables and loans, net	2,289	1,882
Commercial Portfolio Segment [Member] | Commercial Real Estate Automobile [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0	0
Current	3,302	3,151
Finance receivables and loans, net	3,302	3,151
Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	1,540	1,416
Financing Receivables, 30 to 59 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	1,439	1,340
Financing Receivables, 30 to 59 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Residential Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	101	76
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Commercial Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0	0
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Commercial And Industrial Automobile [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0	0
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Commercial And Industrial Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0	0
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Commercial Real Estate Automobile [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0	0
Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	329	327
Financing Receivables, 60 to 89 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	310	293
Financing Receivables, 60 to 89 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Residential Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	19	25
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Commercial Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0	9
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Commercial And Industrial Automobile [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0	9
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Commercial And Industrial Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Commercial Real Estate Automobile [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	274	288
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	180	164
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Residential Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	88	124
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Commercial Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	6	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Commercial And Industrial Automobile [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	6	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Commercial And Industrial Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Commercial Real Estate Automobile [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	$ 0	$ 0