Asset Quality (Impaired Loans) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Financing Receivable, Impaired [Line Items]
Unpaid principal balance - Impaired loans with an associated allowance	$ 2,462,000,000	$ 2,875,000,000
Unpaid principal balance - Impaired loans without an associated allowance	1,102,000,000	1,511,000,000
Unpaid principal balance - Total impaired loans	3,564,000,000	4,386,000,000
Recorded investment - Impaired loans with an associated allowance	2,161,000,000	2,400,000,000
Recorded investment - Impaired loans without an associated allowance	731,000,000	988,000,000
Recorded investment - Total impaired loans	2,892,000,000	3,388,000,000
Associated Allowance - Total impaired loans	463,000,000	625,000,000
Average recorded investment - Impaired loans with an associated allowance	2,249,000,000	2,722,000,000
Average recorded investment - Impaired loans without an associated allowance	908,000,000	948,000,000
Average recorded investment - Total impaired loans	3,157,000,000	3,670,000,000
Specific ALLL reserve for TDRs	386,000,000	470,000,000	587,000,000
Commercial [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance - Impaired loans with an associated allowance	432,000,000	549,000,000
Unpaid principal balance - Impaired loans without an associated allowance	106,000,000	309,000,000
Recorded investment - Impaired loans with an associated allowance	318,000,000	400,000,000
Recorded investment - Impaired loans without an associated allowance	84,000,000	163,000,000
Associated Allowance - Total impaired loans	74,000,000	90,000,000
Average recorded investment - Impaired loans with an associated allowance	360,000,000	442,000,000
Average recorded investment - Impaired loans without an associated allowance	133,000,000	161,000,000
Commercial Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance - Impaired loans with an associated allowance	418,000,000	517,000,000
Unpaid principal balance - Impaired loans without an associated allowance	249,000,000	421,000,000
Recorded investment - Impaired loans with an associated allowance	262,000,000	349,000,000
Recorded investment - Impaired loans without an associated allowance	187,000,000	315,000,000
Associated Allowance - Total impaired loans	65,000,000	89,000,000
Average recorded investment - Impaired loans with an associated allowance	283,000,000	478,000,000
Average recorded investment - Impaired loans without an associated allowance	276,000,000	354,000,000
Home Equity [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance - Impaired loans with an associated allowance	1,021,000,000	999,000,000
Unpaid principal balance - Impaired loans without an associated allowance	403,000,000	366,000,000
Recorded investment - Impaired loans with an associated allowance	984,000,000	992,000,000
Recorded investment - Impaired loans without an associated allowance	145,000,000	124,000,000
Associated Allowance - Total impaired loans	215,000,000	334,000,000
Average recorded investment - Impaired loans with an associated allowance	986,000,000	900,000,000
Average recorded investment - Impaired loans without an associated allowance	134,000,000	166,000,000
Residential Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance - Impaired loans with an associated allowance	397,000,000	573,000,000
Unpaid principal balance - Impaired loans without an associated allowance	344,000,000	415,000,000
Recorded investment - Impaired loans with an associated allowance	420,000,000	436,000,000
Recorded investment - Impaired loans without an associated allowance	315,000,000	386,000,000
Associated Allowance - Total impaired loans	75,000,000	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	365,000,000	267,000,000
Credit Card [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance - Impaired loans with an associated allowance	130,000,000	166,000,000
Recorded investment - Impaired loans with an associated allowance	130,000,000	166,000,000
Associated Allowance - Total impaired loans	32,000,000	36,000,000
Average recorded investment - Impaired loans with an associated allowance	147,000,000	189,000,000
Other Consumer [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance - Impaired loans with an associated allowance	64,000,000	71,000,000
Recorded investment - Impaired loans with an associated allowance	47,000,000	57,000,000
Associated Allowance - Total impaired loans	2,000,000	2,000,000
Average recorded investment - Impaired loans with an associated allowance	$ 51,000,000	$ 68,000,000