Other Noninterest Income and Other Noninterest Expense - Summary of Other Noninterest Income (Parenthetical) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Other Income and Expenses [Abstract]
Foreign Currency Transaction Unrealized Gain Loss Other Instruments Attributable To Noncontrolling Interests	$ 0.3	$ 1.3	$ 0.1	$ 0.8