Finance Receivables And Loans, Net (Past Due Financing Receivables And Loans) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 days past due	$ 1,416	$ 1,227
60 - 89 days past due	327	286
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	288	323
Total past due	2,031	1,836
Current	97,916	98,491
Loans and Leases Receivable, Gross, Excluding Fair Value Option Election	99,947	100,327
Finance receivables and loans, net	99,948	100,328
Consumer Loans Auto Financing Receivable [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 days past due	1,340	1,145
60 - 89 days past due	293	255
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	164	157
Total past due	1,797	1,557
Current	54,773	54,860
Finance receivables and loans, net	56,570	56,417
Residential Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 days past due	76	82
60 - 89 days past due	25	31
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	124	124
Total past due	225	237
Current	7,248	8,206
Loans and Leases Receivable, Gross, Excluding Fair Value Option Election	7,473	8,443
Finance receivables and loans, net	7,474	8,444
Commercial Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 days past due	0	0
60 - 89 days past due	9	0
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	0	42
Total past due	9	42
Current	35,895	35,425
Finance receivables and loans, net	35,904	35,467
Commercial And Industrial Automobile [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 days past due	0	0
60 - 89 days past due	9	0
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	0	36
Total past due	9	36
Current	30,862	30,912
Finance receivables and loans, net	30,871	30,948
Commercial And Industrial Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 days past due	0	0
60 - 89 days past due	0	0
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	0	0
Total past due	0	0
Current	1,882	1,664
Finance receivables and loans, net	1,882	1,664
Commercial Real Estate Automobile [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 days past due	0	0
60 - 89 days past due	0	0
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	0	6
Total past due	0	6
Current	3,151	2,849
Finance receivables and loans, net	$ 3,151	$ 2,855