Postretirement Benefit Plans - Summary of Funded Status of Postretirement Benefit Plans and Presentation of Such Balances within Consolidated Balance Sheet (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 278.0	$ 257.0
Projected benefit obligation	532.6	600.0
Funded status	(254.6)	(343.0)
Amounts reported within:
Non-current assets	1.9	0
Accrued liabilities	(13.2)	(12.7)
Non-current liabilities	(243.3)	(330.3)
Pension [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	268.8	249.1	184.3
Projected benefit obligation	366.0	387.0	330.1
Funded status	(97.2)	(137.9)
Amounts reported within:
Non-current assets	1.9	0
Accrued liabilities	(4.8)	(4.2)
Non-current liabilities	(94.3)	(133.7)
Others Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	9.2	7.9	7.5
Projected benefit obligation	166.6	213.0	191.8
Funded status	(157.4)	(205.1)
Amounts reported within:
Non-current assets	0	0
Accrued liabilities	(8.4)	(8.5)
Non-current liabilities	$ (149.0)	$ (196.6)