Income Tax Expense Allocated to Each Component of Other Comprehensive Income (Loss) (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Other Comprehensive Income [Line Items]
Translation adjustments, Before-Tax Amount	$ 11.4	$ (70.1)	$ 12.6
Adjustment for net periodic pension and other postretirement benefit plan cost, Before-Tax Amount	(285.1)	(485.9)	68.6
Change in fair value of derivatives, Before-Tax Amount	0.8	1.1	0.6
Other comprehensive income (loss), Before-Tax Amount	(272.9)	(554.9)	81.8
Translation adjustments, Income Tax Expense (benefit)
Adjustment for net periodic pension and other postretirement benefit plan cost, Income Tax Expense (benefit)	(107.5)	(182.8)	26.6
Change in fair value of derivatives, Income Tax Expense (benefit)	0.3	0.4	0.3
Other comprehensive income (loss), Income Tax Expense (benefit)	(107.2)	(182.4)	26.9
Translation adjustments, Net-of-Tax Amount	11.4	(70.1)	12.6
Adjustment for net periodic pension and other postretirement benefit plan cost, Net-of-Tax Amount	(177.6)	(303.1)	42.0
Change in fair value of derivatives, Net-of-Tax Amount	0.5	0.7	0.3
Other comprehensive income (loss), Net-of-Tax Amount	$ (165.7)	$ (372.5)	$ 54.9