Other Noninterest Income and Other Noninterest Expense - Summary of Other Noninterest Income (Parenthetical) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Other Income and Expenses [Abstract]
Foreign Currency Transaction Unrealized Gain Loss Other Instruments Attributable To Noncontrolling Interests	$ 0.2	$ 0.6