Summary of Changes in 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]
Balance at Beginning of Period			$ (1,029.2)	$ (863.3)
Other comprehensive loss before reclassifications			(24.6)	(20.6)
Amount reclassified from accumulated other comprehensive loss			9.8	2.7
Net change in accumulated other comprehensive loss			(14.8)	(17.9)
Balance at End of Period	(1,044.0)	(881.2)	(1,044.0)	(881.2)
Fair Value Of Derivative Instruments
Accumulated Other Comprehensive Income Loss [Line Items]
Balance at Beginning of Period			(0.6)	(1.1)
Other comprehensive income (loss) before reclassifications, change in fair value of derivatives				0
Amount reclassified from accumulated other comprehensive loss, change in fair value of derivatives			0.1	0.4
Net change in accumulated other comprehensive loss			0.1	0.4
Balance at End of Period	(0.5)	(0.7)	(0.5)	(0.7)
Pension and Other Postretirement Benefit Plan Cost
Accumulated Other Comprehensive Income Loss [Line Items]
Balance at Beginning of Period			(1,085.1)	(907.5)
Other comprehensive income (loss) before reclassifications, Pension and Other Postretirement Benefits Plan Cost			(5.8)	(0.8)
Amount reclassified from accumulated other comprehensive loss, Pension and Other Postretirement Benefits Plan Cost	4.9	0.8	9.7	2.3
Net change in accumulated other comprehensive loss			3.9	1.5
Balance at End of Period	(1,081.2)	(906.0)	(1,081.2)	(906.0)
Accumulated Translation Adjustment
Accumulated Other Comprehensive Income Loss [Line Items]
Balance at Beginning of Period			56.5	45.3
Other comprehensive income (loss) before reclassifications, translation adjustment			(18.8)	(19.8)
Amount reclassified from accumulated other comprehensive loss, translation adjustment				0
Net change in accumulated other comprehensive loss			(18.8)	(19.8)
Balance at End of Period	$ 37.7	$ 25.5	$ 37.7	$ 25.5