Asset Quality (TDRs that were Modified in the Past Twelve Months which have Subsequently Defaulted) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014 contracts	Jun. 30, 2013 contracts	Jun. 30, 2014 contracts	Jun. 30, 2013 contracts
Financing Receivable, Modifications [Line Items]
Number of Contracts - Subsequently defaulted TDRs	1,668	1,512	2,319	2,940
Recorded Investment - Subsequently defaulted TDRs	$ 66	$ 59	$ 96	$ 106
Total commercial lending [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts - Subsequently defaulted TDRs	37	23	54	44
Recorded Investment - Subsequently defaulted TDRs	37	29	53	49
Total consumer lending [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts - Subsequently defaulted TDRs	1,631	1,489	2,265	2,896
Recorded Investment - Subsequently defaulted TDRs	29	30	43	57
Prior period correction - Recorded Investment		41		49
Prior period correction - Number of contracts		444		483
Commercial [Member] | Total commercial lending [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts - Subsequently defaulted TDRs	23	11	33	26
Recorded Investment - Subsequently defaulted TDRs	16	8	22	18
Commercial Real Estate [Member] | Total commercial lending [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts - Subsequently defaulted TDRs	14	12	21	18
Recorded Investment - Subsequently defaulted TDRs	21	21	31	31
Home Equity [Member] | Total consumer lending [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts - Subsequently defaulted TDRs	100	155	216	300
Recorded Investment - Subsequently defaulted TDRs	6	11	13	21
Residential Real Estate [Member] | Total consumer lending [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts - Subsequently defaulted TDRs	51	67	76	131
Recorded Investment - Subsequently defaulted TDRs	11	9	14	16
Credit Card [Member] | Total consumer lending [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts - Subsequently defaulted TDRs	1,446	1,225	1,894	2,373
Recorded Investment - Subsequently defaulted TDRs	12	9	15	18
Other Consumer [Member] | Total consumer lending [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts - Subsequently defaulted TDRs	34	42	79	92
Recorded Investment - Subsequently defaulted TDRs		$ 1	$ 1	$ 2