CONSOLIDATED STATEMENTS OF EQUITY - USD ($) shares in Thousands, $ in Millions	Common Stock and Additional Paid in Capital	Retained Earnings	Accumulated Other Comprehensive (Loss) Income	Non-controlling Interests	Total
Balance at Dec. 31, 2016	$ 590.3	$ 3,663.2	$ (104.7)	$ 30.3	$ 4,179.1
Balance (in shares) at Dec. 31, 2016	72,683
Increase (Decrease) in Stockholders' Equity
Net income		613.4		7.6	621.0
Other comprehensive income (loss)			33.1		33.1
Dividends to noncontrolling interest holders				(5.1)	(5.1)
Stock-based compensation, net	$ 24.1				24.1
Stock-based compensation, net (in shares)	165
Stock options exercised	$ 5.2				5.2
Stock options exercised (in shares)	99
Repurchase of common shares	$ (25.0)				$ (25.0)
Repurchase of common shares (in shares)	(337)				300
Cash dividends - $2.20, $2.00 and $1.80 per share for the years ended December 31, 2019, 2018 and 2017, respectively		(132.5)			$ (132.5)
Balance at Dec. 31, 2017	$ 594.6	4,144.1	(71.6)	32.8	4,699.9
Balance (in shares) at Dec. 31, 2017	72,610
Increase (Decrease) in Stockholders' Equity
Net income		633.7		8.1	641.8
Other comprehensive income (loss)			(25.6)		(25.6)
Reclassification of stranded tax effects resulting from tax reform		5.5	(5.5)
Noncontrolling interest purchased	$ (9.3)			(19.7)	(29.0)
Dividends to noncontrolling interest holders				(13.3)	(13.3)
Stock-based compensation, net	$ 33.2				33.2
Stock-based compensation, net (in shares)	289
Stock options exercised	$ 2.8				2.8
Stock options exercised (in shares)	48
Repurchase of common shares	$ (484.9)				$ (484.9)
Repurchase of common shares (in shares)	(6,065)				6,100
Cash dividends - $2.20, $2.00 and $1.80 per share for the years ended December 31, 2019, 2018 and 2017, respectively		(145.4)			$ (145.4)
Balance at Dec. 31, 2018	$ 136.4	4,637.9	(102.7)	7.9	$ 4,679.5
Balance (in shares) at Dec. 31, 2018	66,882				66,882
Increase (Decrease) in Stockholders' Equity
Net income		701.5		4.6	$ 706.1
Other comprehensive income (loss)			(2.4)		(2.4)
Noncontrolling interest purchased				(0.4)	(0.4)
Dividends to noncontrolling interest holders				(4.6)	(4.6)
Stock-based compensation, net	$ 35.0				35.0
Stock-based compensation, net (in shares)	545
Stock options exercised	$ 0.8				0.8
Stock options exercised (in shares)	20
Repurchase of common shares	$ (50.0)				$ (50.0)
Repurchase of common shares (in shares)	(593)				600
Cash dividends - $2.20, $2.00 and $1.80 per share for the years ended December 31, 2019, 2018 and 2017, respectively		(149.9)			$ (149.9)
Balance at Dec. 31, 2019	$ 122.2	$ 5,189.5	$ (105.1)	$ 7.5	$ 5,214.1
Balance (in shares) at Dec. 31, 2019	66,854				66,854