Allowance for Credit Losses (Breakdown of Allowance for Loan and Lease Losses Based on Method for Determining Allowance) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Individually Evaluated For Impairment	$ 370	$ 432
Collectively Evaluated For Impairment	1,669	1,711
Loans Acquired With Deteriorated Credit Quality	87	113
Loans and Leases Receivable, Allowance, Total	2,126	2,256
Commercial and Industrial [Member]
Individually Evaluated For Impairment	83	77
Collectively Evaluated For Impairment	442	356
Loans and Leases Receivable, Allowance, Total	525	433
Commercial Real Estate - Other [Member]
Individually Evaluated For Impairment	47	69
Collectively Evaluated For Impairment	258	265
Loans and Leases Receivable, Allowance, Total	305	334
Commercial Real Estate - Residential ADC [Member]
Individually Evaluated For Impairment	28	50
Collectively Evaluated For Impairment	129	236
Loans and Leases Receivable, Allowance, Total	157	286
Commercial Other Lending Subsidiaries [Member]
Individually Evaluated For Impairment	2	1
Collectively Evaluated For Impairment	11	10
Loans and Leases Receivable, Allowance, Total	13	11
Direct Retail Lending [Member]
Individually Evaluated For Impairment	28	35
Collectively Evaluated For Impairment	255	197
Loans and Leases Receivable, Allowance, Total	283	232
Retail Revolving Credit [Member]
Individually Evaluated For Impairment	25	27
Collectively Evaluated For Impairment	65	85
Loans and Leases Receivable, Allowance, Total	90	112
Retail Residential Mortgage [Member]
Individually Evaluated For Impairment	127	152
Collectively Evaluated For Impairment	182	213
Loans and Leases Receivable, Allowance, Total	309	365
Retail Sales Finance [Member]
Individually Evaluated For Impairment	3	1
Collectively Evaluated For Impairment	22	37
Loans and Leases Receivable, Allowance, Total	25	38
Retail Other Lending Subsidiaries [Member]
Individually Evaluated For Impairment	27	20
Collectively Evaluated For Impairment	173	166
Loans and Leases Receivable, Allowance, Total	200	186
Covered and Other Acquired [Member]
Individually Evaluated For Impairment	0	0
Collectively Evaluated For Impairment	52	36
Loans Acquired With Deteriorated Credit Quality	87	113
Loans and Leases Receivable, Allowance, Total	139	149
Unallocated [Member]
Individually Evaluated For Impairment	0	0
Collectively Evaluated For Impairment	80	110
Loans and Leases Receivable, Allowance, Total	$ 80	$ 110