Asset Quality (TDRs which have Subsequently Defaulted) (Details) (Subsequently Defaulted Troubled Debt Restructurings [Member], USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013 contracts	Jun. 30, 2012 contracts	Jun. 30, 2013 contracts	Jun. 30, 2012 contracts
Financing Receivable, Modifications [Line Items]
Number of Contracts	1,956	2,505	3,423	3,650
Recorded Investment	$ 100	$ 104	$ 155	$ 168
Total commercial lending [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts	23	47	44	86
Recorded Investment	29	51	49	66
Total consumer lending [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts	1,933	2,458	3,379	3,564
Recorded Investment	71	53	106	102
Commercial [Member] | Total commercial lending [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts	11	27	26	58
Recorded Investment	8	5	18	15
Commercial Real Estate [Member] | Total commercial lending [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts	12	15	18	23
Recorded Investment	21	35	31	40
Equipment Lease Financing [Member] | Total commercial lending [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts		5		5
Recorded Investment		11		11
Home Equity [Member] | Total consumer lending [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts	402	161	565	366
Recorded Investment	26	14	37	33
Residential Real Estate [Member] | Total consumer lending [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts	251	144	353	307
Recorded Investment	35	23	49	46
Credit Card [Member] | Total consumer lending [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts	1,225	2,114	2,373	2,815
Recorded Investment	9	15	18	20
Other Consumer [Member] | Total consumer lending [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts	55	39	88	76
Recorded Investment	$ 1	$ 1	$ 2	$ 3