Postretirement Benefit Plans - Amount Recognized in Accumulated Other Comprehensive Income Loss (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	$ 166.3	$ 250.7
Prior service cost (benefit)	(19.4)	1.1
Total	146.9	251.8
Pension [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	126.9	175.7
Prior service cost (benefit)	2.8	4.8
Total	129.7	180.5
Others Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	39.4	75.0
Prior service cost (benefit)	(22.2)	(3.7)
Total	$ 17.2	$ 71.3