Condensed Consolidated Statements of Changes in Stockholders' Equity - USD ($) shares in Millions, $ in Millions	Total	Shares	Common Stock and Additional Paid-in Capital	Accumulated Other Comprehensive Loss	Accumulated Deficit	Cumulative Effect, Period of Adoption, Adjustment	Cumulative Effect, Period of Adoption, Adjustment Accumulated Deficit
Balance (in shares) at Dec. 31, 2018		346.4
Balance at Dec. 31, 2018	$ 4,823.2		$ 7,672.8	$ (18.2)	$ (2,831.4)
Balance (Accounting Standards Update 2017-12) at Dec. 31, 2018						$ 0.1	$ 0.1
Balance (Accounting Standards Update 2016-02) at Dec. 31, 2018						$ (4.8)	$ (4.8)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	176.6				176.6
Other comprehensive income (loss), net	(8.6)			(8.6)
Issuance of common stock (in shares)		8.5
Issuance of common stock	55.4		55.4
Common stock assumed upon business combination	4.7		4.7
Repurchase and retirement of common stock (in shares)		(13.9)
Repurchase and retirement of common stock	(354.9)		(181.7)		(173.2)
Share-based compensation expense	147.1		147.1
Payments of cash dividends	(196.4)		(196.4)
Balance (in shares) at Sep. 30, 2019		341.0
Balance at Sep. 30, 2019	4,642.4		7,501.9	(26.8)	(2,832.7)
Balance (in shares) at Jun. 30, 2019		344.5
Balance at Jun. 30, 2019	4,591.2		7,491.2	(11.3)	(2,888.7)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	99.3				99.3
Other comprehensive income (loss), net	(15.5)			(15.5)
Issuance of common stock (in shares)		1.7
Issuance of common stock	25.7		25.7
Repurchase and retirement of common stock (in shares)		(5.2)
Repurchase and retirement of common stock	(111.1)		(67.8)		(43.3)
Purchase of forward contract under accelerated share repurchase program ("ASR")	60.0		60.0
Share-based compensation expense	57.5		57.5
Payments of cash dividends	(64.7)		(64.7)
Balance (in shares) at Sep. 30, 2019		341.0
Balance at Sep. 30, 2019	4,642.4		7,501.9	(26.8)	(2,832.7)
Balance (in shares) at Dec. 31, 2019		335.9
Balance at Dec. 31, 2019	4,610.6		7,370.5	(18.5)	(2,741.4)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	227.0				227.0
Other comprehensive income (loss), net	33.7			33.7
Issuance of common stock (in shares)		8.2
Issuance of common stock	54.5		54.5
Repurchase and retirement of common stock (in shares)		(14.8)
Repurchase and retirement of common stock	(345.7)		(190.9)		(154.8)
Purchase of forward contract under accelerated share repurchase program ("ASR")	40.0		40.0
Share-based compensation expense	138.7		138.7
Payments of cash dividends	(198.0)		(198.0)
Balance (in shares) at Sep. 30, 2020		329.3
Balance at Sep. 30, 2020	4,560.8		7,214.8	15.2	(2,669.2)
Balance (in shares) at Jun. 30, 2020		331.7
Balance at Jun. 30, 2020	4,464.3		7,255.7	(22.9)	(2,768.5)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	145.4				145.4
Other comprehensive income (loss), net	38.1			38.1
Issuance of common stock (in shares)		1.8
Issuance of common stock	26.9		26.9
Repurchase and retirement of common stock (in shares)		(4.2)
Repurchase and retirement of common stock	(100.4)		(54.3)		(46.1)
Share-based compensation expense	52.7		52.7
Payments of cash dividends	(66.2)		(66.2)
Balance (in shares) at Sep. 30, 2020		329.3
Balance at Sep. 30, 2020	$ 4,560.8		$ 7,214.8	$ 15.2	$ (2,669.2)