Condensed Consolidated Statements of Shareholders' Equity (Unaudited) - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Capital in Excess of Par Value	Accumulated Deficit	Accumulated Other Comprehensive Loss	Treasury Stock	Noncontrolling Interests
Balance at beginning of period at Dec. 31, 2015	$ 779.3	$ 1.1	$ 2,834.9	$ (1,696.0)	$ (1.2)	$ (527.4)	$ 167.9
Balance at beginning of period (shares) at Dec. 31, 2015		90.1
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	224.8			182.3			42.5
Receipt of treasury stock	(9.9)					(9.9)
Receipt of treasury stock (shares)		(0.4)
Dividends declared on common stock	(63.4)		(63.4)
Stock-based compensation	16.1		16.1
Stock options exercised	1.8		6.6			(4.8)
Stock options exercised (shares)		0.3
Distributions declared	(43.1)						(43.1)
Capital contributions from consolidated affiliates	17.0						17.0
Fair value adjustments to redeemable noncontrolling interests, net of tax	10.2		10.2
Repurchases of common stock in open market	(24.1)					(24.1)
Repurchases of common stock in open market (shares)		(0.7)
Other	5.1	$ 0.0	2.4	0.0	0.2	(0.7)	3.2
Other (shares)		0.5
Balance at end of period at Sep. 30, 2016	913.8	$ 1.1	2,806.8	(1,513.7)	(1.0)	(566.9)	187.5
Balance at end of period (shares) at Sep. 30, 2016		89.8
Balance at beginning of period at Dec. 31, 2016	928.7	$ 1.1	2,799.1	(1,448.4)	(1.2)	(614.7)	192.8
Balance at beginning of period (shares) at Dec. 31, 2016		88.9
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	239.0			195.7			43.3
Receipt of treasury stock	(19.8)					(19.8)
Receipt of treasury stock (shares)		(0.9)
Dividends declared on common stock	(70.3)		(70.3)
Stock-based compensation	15.2		15.2
Stock options exercised	1.1		20.4			(19.3)
Stock options exercised (shares)		1.1
Stock warrants exercised	26.6		26.6
Stock warrants exercised (shares)		0.7
Distributions declared	(37.1)						(37.1)
Capital contributions from consolidated affiliates	37.8						37.8
Fair value adjustments to redeemable noncontrolling interests, net of tax	(44.4)		(44.4)
Repurchases of common stock in open market	(38.1)					(38.1)
Repurchases of common stock in open market (shares)		(0.9)
Conversion of convertible debt, net of tax			53.7
Conversion of convertible debt, net of tax (shares)		8.9
Stock Issued During Period, Value, Conversion of Convertible Securities	328.2					274.5
Other	6.3		5.7	1.1	0.3	(0.8)	0.0
Other (shares)		0.5
Balance at end of period at Sep. 30, 2017	$ 1,373.2	$ 1.1	$ 2,806.0	$ (1,251.6)	$ (0.9)	$ (418.2)	$ 236.8
Balance at end of period (shares) at Sep. 30, 2017		98.3