CONDENSED CONSOLIDATED STATEMENT OF EQUITY (UNAUDITED) - 6 months ended Jun. 30, 2017 - USD ($) shares in Millions, $ in Millions	Total	Common Stock [Member]	Capital in Excess of Par Value [Member]	Treasury Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]
Balance at Dec. 31, 2016	$ 1,117.5	$ 18.4	$ 260.4	$ (46.1)	$ 1,071.6	$ (186.8)
Balance (in shares) at Dec. 31, 2016		73.7
Increase (Decrease) in Equity [Roll Forward]
Net income	99.7				99.7
Stock-based compensation	7.1		(0.4)	7.5
Shares issued under stock plans (shares)		1.1
Shares issued under stock plans	32.4	$ 0.3	28.0	4.1
Shares repurchased under share repurchase program	(26.9)			(26.9)
Shares repurchased for employee tax withholdings (shares)		0.0
Shares repurchased for employee tax withholdings	(3.8)		(0.4)	(3.4)
Dividends declared	(19.2)				(19.2)
Other adjustments to capital in excess of par value	(4.7)		(4.7)
Other comprehensive income, net of tax	35.0					35.0
Balance at Jun. 30, 2017	1,242.4	$ 18.7	$ 292.3	$ (64.8)	1,148.0	$ (151.8)
Balance (in shares) at Jun. 30, 2017		74.8
Increase (Decrease) in Equity [Roll Forward]
Effect of modified retrospective application of a new accounting standard	$ (4.1)				$ (4.1)