Asset Quality (Impaired Loans) (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2013
Financing Receivable, Impaired [Line Items]
Unpaid principal balance - Impaired loans with an associated allowance	$ 2,731	$ 2,875
Unpaid principal balance - Impaired loans without an associated allowance	1,300	1,511
Unpaid principal balance - Total impaired loans	4,031	4,386
Recorded investment - Impaired loans with an associated allowance	2,270	2,400
Recorded investment - Impaired loans without an associated allowance	923	988
Recorded investment - Total impaired loans	3,193	3,388
Associated Allowance - Total impaired loans	554	625
Average recorded investment - Impaired loans with an associated allowance	2,323	2,722
Average recorded investment - Impaired loans without an associated allowance	969	948
Average recorded investment - Total impaired loans	3,292	3,670
Specific ALLL reserve for TDRs	436	470	507
Commercial [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance - Impaired loans with an associated allowance	490	549
Unpaid principal balance - Impaired loans without an associated allowance	180	309
Recorded investment - Impaired loans with an associated allowance	383	400
Recorded investment - Impaired loans without an associated allowance	140	163
Associated Allowance - Total impaired loans	78	90
Average recorded investment - Impaired loans with an associated allowance	393	442
Average recorded investment - Impaired loans without an associated allowance	149	161
Commercial Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance - Impaired loans with an associated allowance	439	517
Unpaid principal balance - Impaired loans without an associated allowance	354	421
Recorded investment - Impaired loans with an associated allowance	284	349
Recorded investment - Impaired loans without an associated allowance	265	315
Associated Allowance - Total impaired loans	69	89
Average recorded investment - Impaired loans with an associated allowance	305	478
Average recorded investment - Impaired loans without an associated allowance	305	354
Home Equity [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance - Impaired loans with an associated allowance	990	999
Unpaid principal balance - Impaired loans without an associated allowance	388	366
Recorded investment - Impaired loans with an associated allowance	974	992
Recorded investment - Impaired loans without an associated allowance	135	124
Associated Allowance - Total impaired loans	309	334
Average recorded investment - Impaired loans with an associated allowance	986	900
Average recorded investment - Impaired loans without an associated allowance	129	166
Residential Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance - Impaired loans with an associated allowance	601	573
Unpaid principal balance - Impaired loans without an associated allowance	378	415
Recorded investment - Impaired loans with an associated allowance	435	436
Recorded investment - Impaired loans without an associated allowance	383	386
Associated Allowance - Total impaired loans	65	74
Average recorded investment - Impaired loans with an associated allowance	430	645
Average recorded investment - Impaired loans without an associated allowance	386	267
Credit Card [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance - Impaired loans with an associated allowance	145	166
Recorded investment - Impaired loans with an associated allowance	145	166
Associated Allowance - Total impaired loans	31	36
Average recorded investment - Impaired loans with an associated allowance	156	189
Other Consumer [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance - Impaired loans with an associated allowance	66	71
Recorded investment - Impaired loans with an associated allowance	49	57
Associated Allowance - Total impaired loans	2	2
Average recorded investment - Impaired loans with an associated allowance	$ 53	$ 68