CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY - USD ($) shares in Millions, $ in Millions	Total	Cumulative Effect, Period Of Adoption, Adjustment	Common Stock	Treasury Stock	Additional Paid in Capital	Retained Earnings	Retained Earnings Cumulative Effect, Period Of Adoption, Adjustment	Accumulated Other Comprehensive Loss	Accumulated Other Comprehensive Loss Cumulative Effect, Period Of Adoption, Adjustment	Non-controlling Interest in Subsidiaries
Balance at beginning of period (in shares) at Dec. 31, 2019			283.8	75.1
Balance at beginning of period at Dec. 31, 2019	$ 360.4	$ (6.5)	$ 2.8	$ (1,832.8)	$ 573.9	$ 1,703.3	$ (6.5)	$ (87.7)		$ 0.9
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	204.1					204.1
Net (loss) income attributable to non-controlling interests	0.1									0.1
Foreign currency adjustments, net of tax	(0.2)							(0.2)
Exercise of stock options	2.4			$ 0.5	1.9
Issuances of PRSUs, RSUs, and DSUs (in shares)				(0.4)
Issuances of PRSUs, RSUs, and DSUs	0.0			$ 5.8	(5.8)
Treasury stock repurchased (in shares)				2.6
Treasury stock repurchased	(187.5)			$ (187.5)
Treasury stock repurchased - PRSU/RSU releases (in shares)				0.1
Treasury stock repurchased - PRSU/RSU releases	(12.1)			$ (12.1)
Amortization of unearned stock-based compensation	86.6				86.6
Balance at ending of period (in shares) at Sep. 30, 2020			283.8	77.4
Balance at end of period at Sep. 30, 2020	447.3		$ 2.8	$ (2,026.1)	656.6	1,900.9		(87.9)		1.0
Redeemable noncontrolling interest, beginning balance at Dec. 31, 2019	0.0
Increase (Decrease) in Temporary Equity [Roll Forward]
Net (loss) income attributable to non-controlling interests	0.6
Acquisition of non-controlling interest in subsidiary	8.4
Dividend paid to non-controlling interest in subsidiary	(0.1)
Redeemable noncontrolling interest, ending balance at Sep. 30, 2020	8.9
Balance at beginning of period (in shares) at Jun. 30, 2020			283.8	77.4
Balance at beginning of period at Jun. 30, 2020	241.0		$ 2.8	$ (2,026.3)	584.2	1,779.5		(100.0)		0.8
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	121.4					121.4
Net (loss) income attributable to non-controlling interests	0.2									0.2
Foreign currency adjustments, net of tax	12.1							12.1
Exercise of stock options	0.9			0.2	0.7
Issuances of PRSUs, RSUs, and DSUs	0.0			0.1	(0.1)
Treasury stock repurchased - PRSU/RSU releases	(0.1)			$ (0.1)
Amortization of unearned stock-based compensation	71.8				71.8
Balance at ending of period (in shares) at Sep. 30, 2020			283.8	77.4
Balance at end of period at Sep. 30, 2020	447.3		$ 2.8	$ (2,026.1)	656.6	1,900.9		(87.9)		1.0
Redeemable noncontrolling interest, beginning balance at Jun. 30, 2020	8.7
Increase (Decrease) in Temporary Equity [Roll Forward]
Net (loss) income attributable to non-controlling interests	0.2
Redeemable noncontrolling interest, ending balance at Sep. 30, 2020	8.9
Balance at beginning of period (in shares) at Dec. 31, 2020			283.8	78.9
Balance at beginning of period at Dec. 31, 2020	504.6		$ 2.8	$ (2,096.8)	617.5	2,045.6		(65.5)		1.0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	448.7					448.7
Net (loss) income attributable to non-controlling interests	0.2									0.2
Purchase of remaining interest in subsidiary	(4.6)				(3.4)					(1.2)
Foreign currency adjustments, net of tax	(34.0)							(34.0)
Exercise of stock options (in shares)				(0.9)
Exercise of stock options	14.4			$ 25.0	(10.6)
Dividends declared on common stock	(47.3)					(47.3)
Issuances of PRSUs, RSUs, and DSUs (in shares)				(1.6)
Issuances of PRSUs, RSUs, and DSUs	0.0			$ 41.8	(41.8)
Treasury stock repurchased (in shares)				14.1
Treasury stock repurchased	(551.4)			$ (551.4)
Treasury stock repurchased - PRSU/RSU releases (in shares)				0.5
Treasury stock repurchased - PRSU/RSU releases	(14.4)			$ (14.4)
Amortization of unearned stock-based compensation	46.3				46.3
Balance at ending of period (in shares) at Sep. 30, 2021			283.8	91.0
Balance at end of period at Sep. 30, 2021	362.5		$ 2.8	$ (2,595.8)	608.0	2,447.0		(99.5)		0.0
Redeemable noncontrolling interest, beginning balance at Dec. 31, 2020	8.9
Increase (Decrease) in Temporary Equity [Roll Forward]
Net (loss) income attributable to non-controlling interests	(0.4)
Redeemable noncontrolling interest, ending balance at Sep. 30, 2021	8.5
Balance at beginning of period (in shares) at Jun. 30, 2021			283.8	87.3
Balance at beginning of period at Jun. 30, 2021	401.6		$ 2.8	$ (2,416.6)	597.1	2,287.9		(69.6)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	177.4					177.4
Foreign currency adjustments, net of tax	(29.9)							(29.9)
Exercise of stock options (in shares)				(0.4)
Exercise of stock options	5.9			$ 10.7	(4.8)
Dividends declared on common stock	(18.3)					(18.3)
Issuances of PRSUs, RSUs, and DSUs	0.0			$ 0.4	(0.4)
Treasury stock repurchased (in shares)				4.1
Treasury stock repurchased	(190.0)			$ (190.0)
Treasury stock repurchased - PRSU/RSU releases	(0.3)			$ (0.3)
Amortization of unearned stock-based compensation	16.1				16.1
Balance at ending of period (in shares) at Sep. 30, 2021			283.8	91.0
Balance at end of period at Sep. 30, 2021	362.5		$ 2.8	$ (2,595.8)	$ 608.0	$ 2,447.0		$ (99.5)		$ 0.0
Redeemable noncontrolling interest, beginning balance at Jun. 30, 2021	8.5
Increase (Decrease) in Temporary Equity [Roll Forward]
Net (loss) income attributable to non-controlling interests	0.0
Redeemable noncontrolling interest, ending balance at Sep. 30, 2021	$ 8.5