Unaudited Interim Financial Information (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended												12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015		Sep. 30, 2015		Jun. 30, 2015		Mar. 31, 2015		Dec. 31, 2016	Dec. 31, 2015		Dec. 31, 2014
Quarterly Financial Data [Line Items]
Net sales	$ 967.1	$ 941.9	$ 931.5	$ 873.5	$ 870.8		$ 865.7		$ 859.8		$ 819.7		$ 3,714.0	$ 3,416.0		$ 3,323.6
Cost of goods sold	348.1	352.2	351.0	320.4	320.0		336.3		333.7		311.2		1,371.7	1,301.2		1,258.6
Income (loss) from operations before income taxes	200.9	112.2	207.7	142.9	158.0		(52.4)		59.2		184.6		663.7	349.4		445.8
Net income (loss)	$ 159.6	$ 96.4	$ 159.2	$ 116.2	$ 136.3		$ (86.0)		$ (54.7)		$ 139.8		$ 531.4	$ 135.4		$ 294.5
Basic earnings (loss) per share available to common shareholders	$ 2.15	$ 1.30	$ 2.14	$ 1.56	$ 1.82	[1]	$ (1.16)	[1]	$ (0.74)	[1]	$ 1.85	[1]	$ 7.15	$ 1.80	[1]	$ 3.83
Diluted earnings (loss) per share available to common shareholders	$ 2.11	$ 1.27	$ 2.11	$ 1.54	$ 1.79	[1]	$ (1.16)	[1],[2]	$ (0.74)	[1],[2]	$ 1.82	[1]	$ 7.03	$ 1.77	[1]	$ 3.76

[1] Total per share amounts may not add due to rounding.

[2] Common share equivalents primarily from share-based compensation plans were not included in the computation of diluted weighted average shares outstanding because their effect would have been antidilutive.