CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Millions, $ in Millions	Common Stock	Preferred Stock	Additional Paid-In Capital	Treasury Stock	Retained Earnings	Accumulated Other Comprehensive Loss	Total
Balance at Dec. 31, 2016	$ 1.1		$ 3,046.1	$ (4,733.1)	$ 3,494.8	$ (150.7)	$ 1,658.2
Balance (in shares) at Dec. 31, 2016	112.5
Increase (Decrease) in Stockholders' Equity
Net income					788.7		788.7
Other comprehensive income						10.5	10.5
Stock-based compensation			75.1				75.1
Repurchases of common stock			(14.3)	(539.4)			(553.7)
Dividends and dividend equivalent rights declared					(116.4)		(116.4)
Other			(7.1)				(7.1)
Other (in shares)	0.3
Balance at Dec. 31, 2017	$ 1.1		3,099.8	(5,272.5)	4,167.1	(140.2)	1,855.3
Balance (in shares) at Dec. 31, 2017	112.8
Increase (Decrease) in Stockholders' Equity
Net income					963.1		963.1
Other comprehensive income						2.1	2.1
Stock-based compensation			80.8				80.8
Repurchases of common stock				(443.2)			(443.2)
Dividends and dividend equivalent rights declared					(125.9)		(125.9)
Cumulative effect adjustment to retained earnings | Accounting Standards Update ASC 606					9.6		9.6
Cumulative effect adjustment to retained earnings | Accounting Standards Update ASU 2016-01					(1.5)		(1.5)
Other			(8.2)				(8.2)
Other (in shares)	0.2
Balance at Dec. 31, 2018	$ 1.1		3,172.4	(5,715.7)	5,012.4	(138.1)	2,332.1
Balance (in shares) at Dec. 31, 2018	113.0
Increase (Decrease) in Stockholders' Equity
Net income					278.0		278.0
Recognition resulting from the sale of Epsilon's foreign subsidiaries						26.8	26.8
Other comprehensive income						38.2	38.2
Stock-based compensation			54.5				54.5
Issuance of stock			42.1	(42.1)
Issuance of stock (in shares)		0.2
Covnersion of preferred stock to common stock (in shares)	1.5	(0.2)
Repurchases of common stock				(976.1)			(976.1)
Dividends and dividend equivalent rights declared					(127.1)		(127.1)
Other			(11.3)				(11.3)
Other (in shares)	0.5
Balance at Dec. 31, 2019	$ 1.1		$ 3,257.7	$ (6,733.9)	$ 5,163.3	$ (99.9)	$ 1,588.3
Balance (in shares) at Dec. 31, 2019	115.0