Asset Quality (Financial Impact and TDRs by Concession Type) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014 loans	Jun. 30, 2013 loans	Jun. 30, 2014 loans	Jun. 30, 2013 loans
Financing Receivable, Modifications [Line Items]
Number of Loans	2,713	4,240	5,836	8,441
Pre-TDR Recorded Investment	$ 168	$ 266	$ 339	$ 587
Post-TDR Recorded Investment	160	213	310	494
Principal Forgiveness [Member]
Financing Receivable, Modifications [Line Items]
Post-TDR Recorded Investment	3	10	22	16
Rate Reduction [Member]
Financing Receivable, Modifications [Line Items]
Post-TDR Recorded Investment	38	83	78	192
Other [Member]
Financing Receivable, Modifications [Line Items]
Post-TDR Recorded Investment	119	120	210	286
Total commercial lending [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	52	82	109	150
Pre-TDR Recorded Investment	88	121	170	298
Post-TDR Recorded Investment	83	81	151	227
Total commercial lending [Member] | Principal Forgiveness [Member]
Financing Receivable, Modifications [Line Items]
Post-TDR Recorded Investment	3	10	22	16
Total commercial lending [Member] | Rate Reduction [Member]
Financing Receivable, Modifications [Line Items]
Post-TDR Recorded Investment	8	15	8	57
Total commercial lending [Member] | Other [Member]
Financing Receivable, Modifications [Line Items]
Post-TDR Recorded Investment	72	56	121	154
Total consumer lending [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	2,661	4,158	5,727	8,291
Pre-TDR Recorded Investment	80	145	169	289
Post-TDR Recorded Investment	77	132	159	267
Total consumer lending [Member] | Rate Reduction [Member]
Financing Receivable, Modifications [Line Items]
Post-TDR Recorded Investment	30	68	70	135
Total consumer lending [Member] | Other [Member]
Financing Receivable, Modifications [Line Items]
Post-TDR Recorded Investment	47	64	89	132
Commercial [Member] | Total commercial lending [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	29	47	63	79
Pre-TDR Recorded Investment	48	61	89	103
Post-TDR Recorded Investment	47	46	85	72
Commercial [Member] | Total commercial lending [Member] | Principal Forgiveness [Member]
Financing Receivable, Modifications [Line Items]
Post-TDR Recorded Investment	3	4	3	4
Commercial [Member] | Total commercial lending [Member] | Rate Reduction [Member]
Financing Receivable, Modifications [Line Items]
Post-TDR Recorded Investment	4	13	4	15
Commercial [Member] | Total commercial lending [Member] | Other [Member]
Financing Receivable, Modifications [Line Items]
Post-TDR Recorded Investment	40	29	78	53
Commercial Real Estate [Member] | Total commercial lending [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	23	34	46	70
Pre-TDR Recorded Investment	40	57	81	192
Post-TDR Recorded Investment	36	35	66	155
Commercial Real Estate [Member] | Total commercial lending [Member] | Principal Forgiveness [Member]
Financing Receivable, Modifications [Line Items]
Post-TDR Recorded Investment		6	19	12
Commercial Real Estate [Member] | Total commercial lending [Member] | Rate Reduction [Member]
Financing Receivable, Modifications [Line Items]
Post-TDR Recorded Investment	4	2	4	42
Commercial Real Estate [Member] | Total commercial lending [Member] | Other [Member]
Financing Receivable, Modifications [Line Items]
Post-TDR Recorded Investment	32	27	43	101
Equipment Lease Financing [Member] | Total commercial lending [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans		1		1
Pre-TDR Recorded Investment		3		3
Home Equity [Member] | Total consumer lending [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	561	1,165	1,392	2,123
Pre-TDR Recorded Investment	40	87	92	160
Post-TDR Recorded Investment	38	76	85	143
Home Equity [Member] | Total consumer lending [Member] | Rate Reduction [Member]
Financing Receivable, Modifications [Line Items]
Post-TDR Recorded Investment	9	43	29	82
Home Equity [Member] | Total consumer lending [Member] | Other [Member]
Financing Receivable, Modifications [Line Items]
Post-TDR Recorded Investment	29	33	56	61
Residential Real Estate [Member] | Total consumer lending [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	161	267	280	587
Pre-TDR Recorded Investment	22	33	40	79
Post-TDR Recorded Investment	22	32	40	77
Residential Real Estate [Member] | Total consumer lending [Member] | Rate Reduction [Member]
Financing Receivable, Modifications [Line Items]
Post-TDR Recorded Investment	7	7	13	19
Residential Real Estate [Member] | Total consumer lending [Member] | Other [Member]
Financing Receivable, Modifications [Line Items]
Post-TDR Recorded Investment	15	25	27	58
Credit Card [Member] | Total consumer lending [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	1,717	2,288	3,568	4,663
Pre-TDR Recorded Investment	14	18	29	35
Post-TDR Recorded Investment	14	17	28	33
Credit Card [Member] | Total consumer lending [Member] | Rate Reduction [Member]
Financing Receivable, Modifications [Line Items]
Post-TDR Recorded Investment	14	17	28	33
Other Consumer [Member] | Total consumer lending [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	222	438	487	918
Pre-TDR Recorded Investment	4	7	8	15
Post-TDR Recorded Investment	3	7	6	14
Other Consumer [Member] | Total consumer lending [Member] | Rate Reduction [Member]
Financing Receivable, Modifications [Line Items]
Post-TDR Recorded Investment		1		1
Other Consumer [Member] | Total consumer lending [Member] | Other [Member]
Financing Receivable, Modifications [Line Items]
Post-TDR Recorded Investment	$ 3	$ 6	$ 6	$ 13