Asset Quality (Impaired Loans) (Details) (USD $)	6 Months Ended	12 Months Ended
	Jun. 30, 2013	Dec. 31, 2012
Financing Receivable, Impaired [Line Items]
Unpaid principal balance - Impaired loans with an associated allowance	$ 3,233,000,000	$ 3,831,000,000
Unpaid principal balance - Impaired loans without an associated allowance	1,594,000,000	1,409,000,000
Unpaid principal balance - Total impaired loans	4,827,000,000	5,240,000,000
Recorded investment - Impaired loans with an associated allowance	2,677,000,000	3,083,000,000
Recorded investment - Impaired loans without an associated allowance	1,005,000,000	833,000,000
Recorded investment - Total impaired loans	3,682,000,000	3,916,000,000
Associated Allowance - Total impaired loans	710,000,000	840,000,000
Average recorded investment - Impaired loans with an associated allowance	2,901,000,000	3,272,000,000
Average recorded investment - Impaired loans without an associated allowance	890,000,000	674,000,000
Average recorded investment - Total impaired loans	3,791,000,000	3,946,000,000
Amounts included in ALLL for TDRs	500,000,000	600,000,000
Commercial [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance - Impaired loans with an associated allowance	636,000,000	824,000,000
Unpaid principal balance - Impaired loans without an associated allowance	376,000,000	362,000,000
Recorded investment - Impaired loans with an associated allowance	444,000,000	523,000,000
Recorded investment - Impaired loans without an associated allowance	155,000,000	126,000,000
Associated Allowance - Total impaired loans	117,000,000	150,000,000
Average recorded investment - Impaired loans with an associated allowance	475,000,000	653,000,000
Average recorded investment - Impaired loans without an associated allowance	141,000,000	157,000,000
Commercial Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance - Impaired loans with an associated allowance	702,000,000	851,000,000
Unpaid principal balance - Impaired loans without an associated allowance	531,000,000	562,000,000
Recorded investment - Impaired loans with an associated allowance	481,000,000	594,000,000
Recorded investment - Impaired loans without an associated allowance	359,000,000	355,000,000
Associated Allowance - Total impaired loans	111,000,000	143,000,000
Average recorded investment - Impaired loans with an associated allowance	548,000,000	778,000,000
Average recorded investment - Impaired loans without an associated allowance	363,000,000	400,000,000
Home Equity [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance - Impaired loans with an associated allowance	1,033,000,000	1,070,000,000
Unpaid principal balance - Impaired loans without an associated allowance	292,000,000	169,000,000
Recorded investment - Impaired loans with an associated allowance	1,012,000,000	1,013,000,000
Recorded investment - Impaired loans without an associated allowance	118,000,000	121,000,000
Associated Allowance - Total impaired loans	354,000,000	328,000,000
Average recorded investment - Impaired loans with an associated allowance	1,014,000,000	851,000,000
Average recorded investment - Impaired loans without an associated allowance	107,000,000	40,000,000
Residential Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance - Impaired loans with an associated allowance	589,000,000	778,000,000
Unpaid principal balance - Impaired loans without an associated allowance	395,000,000	316,000,000
Recorded investment - Impaired loans with an associated allowance	479,000,000	663,000,000
Recorded investment - Impaired loans without an associated allowance	373,000,000	231,000,000
Associated Allowance - Total impaired loans	86,000,000	168,000,000
Average recorded investment - Impaired loans with an associated allowance	589,000,000	700,000,000
Average recorded investment - Impaired loans without an associated allowance	279,000,000	77,000,000
Credit Card [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance - Impaired loans with an associated allowance	209,000,000	204,000,000
Recorded investment - Impaired loans with an associated allowance	208,000,000	204,000,000
Associated Allowance - Total impaired loans	39,000,000	48,000,000
Average recorded investment - Impaired loans with an associated allowance	202,000,000	227,000,000
Other Consumer [Member]
Financing Receivable, Impaired [Line Items]
Unpaid principal balance - Impaired loans with an associated allowance	64,000,000	104,000,000
Recorded investment - Impaired loans with an associated allowance	53,000,000	86,000,000
Associated Allowance - Total impaired loans	3,000,000	3,000,000
Average recorded investment - Impaired loans with an associated allowance	$ 73,000,000	$ 63,000,000