Components of Accumulated Other Comprehensive Income (Loss) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance			$ (283.0)	$ (345.6)
Net Change	(66.6)	2.2	(67.7)	71.5
Ending Balance	(350.7)	(274.1)	(350.7)	(274.1)
Net Unrealized Gains (Losses) on Securities Available for Sale
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance			101.0	39.8
Net Change			(80.2)	31.7
Ending Balance	20.8	71.5	20.8	71.5
Net Unrealized Gains (Losses) on Cash Flow Hedge Designations
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance			(1.4)	(7.0)
Net Change			(3.1)	2.4
Ending Balance	(4.5)	(4.6)	(4.5)	(4.6)
Foreign Currency Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance			10.5	(9.5)
Net Change			1.6	9.9
Ending Balance	12.1	0.4	12.1	0.4
Net Pension and Other Postretirement Benefit Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance			(393.1)	(368.9)
Net Change			14.0	27.5
Ending Balance	$ (379.1)	$ (341.4)	$ (379.1)	$ (341.4)