Subsequent Events (Details) (USD $)	0 Months Ended			0 Months Ended
	Nov. 13, 2012	Nov. 13, 2012 Depositary shares	Nov. 05, 2013 Subsequent Events	Nov. 07, 2013 Subsequent Events Non-cumulative perpetual preferred stock, Series D	Nov. 07, 2013 Subsequent Events Depositary shares
Subsequent events
Depositary shares of preferred stock issued		7,000,000			4,000,000
Depositary shares (in dollars per share)		$ 25.00			$ 25.00
Interest of each depositary share in a share of preferred stock public offered		0.025			0.025
Percentage of dividend on preferred stock	5.50%			6.75%
Net proceeds from issuance of depositary shares		$ 169,900,000			$ 97,000,000
Transfer of debt securities from available-for-sale to held-to-maturity			$ 1,000,000,000