Cash Flow Hedge Derivative Gains and Losses Recognized in AOCI and the Amounts Reclassified to Earnings (Detail) (Asset And Liability Management, USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Foreign Exchange Contracts
Derivative Instruments, Gain (Loss) [Line Items]
Net Gain/(Loss) Recognized in AOCI	$ (15.8)	$ (1.0)	$ 2.9	$ 15.8
Net Gain/(Loss) Reclassified from AOCI to Earnings Trust, Investment and Other Servicing Fees		1.1		0.3
Other Operating Income	(0.8)	0.1	(2.3)	0.2
Interest Income		(0.4)		(0.8)
Interest Expense
Compensation		0.1		2.4
Employee Benefits		0.1		0.7
Equipment and Software				0.1
Occupancy Expense				0.4
Other Operating Expense	(0.9)	1.1	1.4	1.3
Total	(1.7)	2.1	(0.9)	4.6
Interest Rate Swap Contracts
Derivative Instruments, Gain (Loss) [Line Items]
Net Gain/(Loss) Recognized in AOCI		0.1		0.1
Interest Expense