Summary of Significant Accounting Policies Significant Accounting Policies (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014 Locations	Dec. 31, 2013
Accounting Policies [Abstract]
Locations	350
Amortization period of annual fees on credit card loans, months	12 months
Period past due loans are placed on non-accrual, days	90 days
Consumer loans charged down to fair value, days delinquent	120 days
Past due dredit card loans are charged off at this point	180 days
Long-term agreements to resell	$ 1,050,000,000	$ 1,150,000,000
Securities accepted as collateral	1,100,000,000
Securities sold under agreements to repurchase	1,900,000,000
Available for sale securities as collateral for repurchase agreements	$ 1,900,000,000
Common stock dividend rate percentage	5.00%