Condensed Consolidated Statement of Changes in Stockholder's Equity - USD ($) $ in Millions	Common Stock	Treasury Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income, net	Redeemable Noncontrolling Interests	Total
Beginning balance at Dec. 31, 2018	$ 1.2	$ (720.1)	$ 2,660.2	$ 1,288.2	$ 11.5	$ 9.4	$ 3,241.0
Increase (Decrease) in Stockholders' Equity
Cash dividends on common stock				(34.8)			(34.8)
Stock-based compensation			5.4				5.4
Exercise of common stock options			8.1				8.1
Repurchases of common stock from employee stock plans		(10.0)					(10.0)
Purchase of common stock		(35.0)					(35.0)
Shares issued under employee stock purchase plan		0.8					0.8
Net income excluding noncontrolling interest				95.4			95.4
Other comprehensive income (loss)					14.7		14.7
Net loss attributable to redeemable noncontrolling interest						(0.2)
Redemption value adjustment of redeemable noncontrolling interest				(0.2)		0.2	(0.2)
Ending balance at Mar. 31, 2019	1.2	(764.3)	2,673.7	1,348.6	26.2	$ 9.4	3,285.4
Beginning balance at Dec. 31, 2019	1.2	(887.1)	2,691.3	1,512.6	37.6		3,355.6
Increase (Decrease) in Stockholders' Equity
Cash dividends on common stock				(40.0)			(40.0)
Stock-based compensation			8.3				8.3
Repurchases of common stock from employee stock plans		(13.9)					(13.9)
Purchase of common stock		(119.5)					(119.5)
Shares issued under employee stock purchase plan			0.1				0.1
Net income excluding noncontrolling interest				157.4			157.4
Other comprehensive income (loss)					(37.5)		(37.5)
Ending balance at Mar. 31, 2020	$ 1.2	$ (1,020.5)	$ 2,699.7	1,629.6	$ 0.1		3,310.1
Increase (Decrease) in Stockholders' Equity
Transition adjustment for adoption of Current Expected Credit Losses standard at January 1, 2020				$ (0.4)			$ (0.4)