Summary of Changes in Accumulated Other Comprehensive Income (Loss) (Detail) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Accumulated Other Comprehensive Income Loss [Line Items]
Balance at Beginning of Period	$ (488.1)	$ (1,029.2)
Other comprehensive income (loss) before reclassifications	(0.1)	(24.6)
Amount reclassified from accumulated other comprehensive loss	2.4	9.8
Net change in accumulated other comprehensive loss	2.3	(14.8)
Balance at End of Period	(485.8)	(1,044.0)
Changes in the Fair Value Of Derivatives
Accumulated Other Comprehensive Income Loss [Line Items]
Balance at Beginning of Period	(0.2)	(0.6)
Amount reclassified from accumulated other comprehensive loss, change in fair value of derivatives	0.1	0.1
Net change in accumulated other comprehensive loss	0.1	0.1
Balance at End of Period	(0.1)	(0.5)
Pension and Other Postretirement Benefit Plan Cost
Accumulated Other Comprehensive Income Loss [Line Items]
Balance at Beginning of Period	(521.4)	(1,085.1)
Other comprehensive income (loss) before reclassifications, Pension and Other Postretirement Benefits Plan Cost	0	(5.8)
Amount reclassified from accumulated other comprehensive loss, Pension and Other Postretirement Benefits Plan Cost	2.3	9.7
Net change in accumulated other comprehensive loss	2.3	3.9
Balance at End of Period	(519.1)	(1,081.2)
Translation Adjustments
Accumulated Other Comprehensive Income Loss [Line Items]
Balance at Beginning of Period	33.5	56.5
Other comprehensive income (loss) before reclassifications, translation adjustment	(0.1)	(18.8)
Amount reclassified from accumulated other comprehensive loss, translation adjustment
Net change in accumulated other comprehensive loss	(0.1)	(18.8)
Balance at End of Period	$ 33.4	$ 37.7