Other Noninterest Income and Other Noninterest Expense Summary of Other Noninterest Income (Parenthetical) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Disclosure Summary Of Other Noninterest Income [Abstract]
Foreign Currency Transaction Unrealized Gain Loss Other Instruments Attributable To Noncontrolling Interests	$ 0.8	$ (1.7)	$ 0	$ (1.6)