Amounts in Accumulated Other Comprehensive Loss (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Net actuarial (loss) gain	$ (957.5)	$ (1,828.9)
Net transition obligation	(0.2)	(0.2)
Net prior service credit
Total	(957.7)	(1,829.1)
Other Postretirement Benefit Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Net actuarial (loss) gain	35.6	(1.6)
Net transition obligation
Net prior service credit	78.4	68.0
Total	$ 114.0	$ 66.4