Asset Quality (Nonperforming Assets) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Nonperforming loans	$ 2,612	$ 3,088
OREO and Foreclosed Assets	363	369
Total nonperforming assets	2,975	3,457
Nonperforming loans to total loans	1.30%	1.58%
Nonperforming assets to total loans, OREO and foreclosed assets	1.48%	1.76%
Nonperforming assets to total assets	0.89%	1.08%
Exclusions from OREO	214	245
Total commercial lending [Member]
Nonperforming loans	718	980
Total consumer lending [Member]
Nonperforming loans	1,894	2,108
Commercial [Member]
Nonperforming loans	320	457
Commercial [Member] | Total commercial lending [Member]
Nonperforming loans	320	457
Commercial Real Estate [Member]
Nonperforming loans	395	518
Commercial Real Estate [Member] | Total commercial lending [Member]
Nonperforming loans	395	518
Equipment Lease Financing [Member]
Nonperforming loans	3	5
Equipment Lease Financing [Member] | Total commercial lending [Member]
Nonperforming loans	3	5
Home Equity [Member]
Nonperforming loans	1,090	1,139
Home Equity [Member] | Total consumer lending [Member]
Nonperforming loans	1,090	1,139
Residential Real Estate [Member]
Nonperforming loans	743	904
Residential Real Estate [Member] | Total consumer lending [Member]
Nonperforming loans	743	904
Credit Card [Member]
Nonperforming loans	3	4
Credit Card [Member] | Total consumer lending [Member]
Nonperforming loans	3	4
Other Consumer [Member]
Nonperforming loans	58	61
Other Consumer [Member] | Total consumer lending [Member]
Nonperforming loans	58	61
OREO [Member]
OREO and Foreclosed Assets	353	360
Foreclosed and Other Assets [Member]
OREO and Foreclosed Assets	$ 10	$ 9