Asset Quality (Impaired Loans) (Details) (USD $)	9 Months Ended	12 Months Ended
	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2013
Financing Receivable, Impaired [Line Items]
Unpaid principal balance - Impaired loans with an associated allowance	$ 2,516,000,000	$ 2,875,000,000
Unpaid principal balance - Impaired loans without an associated allowance	1,316,000,000	1,511,000,000
Unpaid principal balance - Total impaired loans	3,832,000,000	4,386,000,000
Recorded investment - Impaired loans with an associated allowance	2,123,000,000	2,400,000,000
Recorded investment - Impaired loans without an associated allowance	895,000,000	988,000,000
Recorded investment - Total impaired loans	3,018,000,000	3,388,000,000
Associated Allowance - Total impaired loans	506,000,000	625,000,000
Average recorded investment - Impaired loans with an associated allowance	2,273,000,000	2,722,000,000
Average recorded investment - Impaired loans without an associated allowance	951,000,000	948,000,000
Average recorded investment - Total impaired loans	3,224,000,000	3,670,000,000
Specific ALLL reserve for TDRs	408,000,000	470,000,000	510,000,000
Commercial [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance - Impaired loans with an associated allowance	424,000,000	549,000,000
Unpaid principal balance - Impaired loans without an associated allowance	171,000,000	309,000,000
Recorded investment - Impaired loans with an associated allowance	305,000,000	400,000,000
Recorded investment - Impaired loans without an associated allowance	132,000,000	163,000,000
Associated Allowance - Total impaired loans	64,000,000	90,000,000
Average recorded investment - Impaired loans with an associated allowance	371,000,000	442,000,000
Average recorded investment - Impaired loans without an associated allowance	145,000,000	161,000,000
Commercial Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance - Impaired loans with an associated allowance	366,000,000	517,000,000
Unpaid principal balance - Impaired loans without an associated allowance	376,000,000	421,000,000
Recorded investment - Impaired loans with an associated allowance	242,000,000	349,000,000
Recorded investment - Impaired loans without an associated allowance	275,000,000	315,000,000
Associated Allowance - Total impaired loans	60,000,000	89,000,000
Average recorded investment - Impaired loans with an associated allowance	289,000,000	478,000,000
Average recorded investment - Impaired loans without an associated allowance	298,000,000	354,000,000
Home Equity [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance - Impaired loans with an associated allowance	1,016,000,000	999,000,000
Unpaid principal balance - Impaired loans without an associated allowance	389,000,000	366,000,000
Recorded investment - Impaired loans with an associated allowance	989,000,000	992,000,000
Recorded investment - Impaired loans without an associated allowance	137,000,000	124,000,000
Associated Allowance - Total impaired loans	287,000,000	334,000,000
Average recorded investment - Impaired loans with an associated allowance	987,000,000	900,000,000
Average recorded investment - Impaired loans without an associated allowance	131,000,000	166,000,000
Residential Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance - Impaired loans with an associated allowance	506,000,000	573,000,000
Unpaid principal balance - Impaired loans without an associated allowance	380,000,000	415,000,000
Recorded investment - Impaired loans with an associated allowance	400,000,000	436,000,000
Recorded investment - Impaired loans without an associated allowance	351,000,000	386,000,000
Associated Allowance - Total impaired loans	63,000,000	74,000,000
Average recorded investment - Impaired loans with an associated allowance	422,000,000	645,000,000
Average recorded investment - Impaired loans without an associated allowance	377,000,000	267,000,000
Credit Card [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance - Impaired loans with an associated allowance	139,000,000	166,000,000
Recorded investment - Impaired loans with an associated allowance	139,000,000	166,000,000
Associated Allowance - Total impaired loans	30,000,000	36,000,000
Average recorded investment - Impaired loans with an associated allowance	152,000,000	189,000,000
Other Consumer [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance - Impaired loans with an associated allowance	65,000,000	71,000,000
Recorded investment - Impaired loans with an associated allowance	48,000,000	57,000,000
Associated Allowance - Total impaired loans	2,000,000	2,000,000
Average recorded investment - Impaired loans with an associated allowance	$ 52,000,000	$ 68,000,000