Consolidated Statement of Stockholders' Equity - USD ($) $ in Millions	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Loss [Member]	Accumulated Deficit [Member]	Treasury Stock [Member]	Noncontrolling Interest in Consolidated Subsidiary [Member]
Balance, beginning (in shares) at Dec. 31, 2012		509,977,999				61,153,654
Balance, beginning at Dec. 31, 2012	$ 1,427.9	$ 5.1	$ 3,156.4	$ (41.1)	$ (1,255.7)	$ (466.4)	$ 29.6
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive (loss) income	147.3			(6.3)	150.4		3.2
Stock option exercises (in shares)		2,084,541
Stock option exercises	12.1	$ 0.1	12.0
Shares issued pursuant to the employee stock purchase plan (in shares)		1,330,919
Shares issued pursuant to the employee stock purchase plan	8.3		8.3
Restricted stock units and stock grant awards issued (in shares)		2,495,483
Restricted stock units and stock grant awards issued	0.0
Shares withheld for employee taxes on restricted stock units (in shares)						581,585
Shares withheld for employee taxes on restricted stock units	(4.5)					$ (4.5)
Share-based compensation expense	$ 32.3		32.3
Repurchase of common stock (in shares)	13,900,000					13,903,415
Repurchase of common stock	$ (101.6)					$ (101.6)
Exchange of convertible notes	1.8		1.8
Balance, ending (in shares) at Dec. 31, 2013		515,888,942				75,638,654
Balance, ending at Dec. 31, 2013	1,523.6	$ 5.2	3,210.8	(47.4)	(1,105.3)	$ (572.5)	32.8
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive (loss) income	198.0			5.9	189.7		2.4
Stock option exercises (in shares)		3,735,048
Stock option exercises	24.9		24.9
Shares issued pursuant to the employee stock purchase plan (in shares)		1,346,677
Shares issued pursuant to the employee stock purchase plan	10.0		10.0
Restricted stock units and stock grant awards issued (in shares)		3,644,895
Restricted stock units and stock grant awards issued	0.0
Shares withheld for employee taxes on restricted stock units (in shares)						976,786
Shares withheld for employee taxes on restricted stock units	(9.1)					$ (9.1)
Share-based compensation expense	$ 45.8		45.8
Repurchase of common stock (in shares)	13,900,000					13,900,105
Repurchase of common stock	$ (121.2)					$ (121.2)
Dividend to non-controlling shareholder of consolidated subsidiary	(4.2)						(4.2)
Acquisition of non-controlling interest	(20.4)		(10.3)				(10.1)
Balance, ending (in shares) at Dec. 31, 2014		524,615,562				90,515,545
Balance, ending at Dec. 31, 2014	1,647.4	$ 5.2	3,281.2	(41.5)	(915.6)	$ (702.8)	20.9
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive (loss) income	$ 208.2			(0.8)	206.2		2.8
Stock option exercises (in shares)	3,500,000	3,487,238
Stock option exercises	$ 27.1	$ 0.1	27.0
Shares issued pursuant to the employee stock purchase plan (in shares)		1,729,100
Shares issued pursuant to the employee stock purchase plan	14.6		14.6
Restricted stock units and stock grant awards issued (in shares)		4,302,821
Restricted stock units and stock grant awards issued	0.0
Shares withheld for employee taxes on restricted stock units (in shares)						1,226,764
Shares withheld for employee taxes on restricted stock units	(14.7)					$ (14.7)
Share-based compensation expense	$ 46.9		46.9
Repurchase of common stock (in shares)	30,400,000					30,352,607
Repurchase of common stock	$ (348.2)					$ (348.2)
Warrants and bond hedge, net	(56.9)		(56.9)
Issuance of convertible notes	107.5		107.5
Balance, ending (in shares) at Dec. 31, 2015		534,134,721				122,094,916
Balance, ending at Dec. 31, 2015	$ 1,631.9	$ 5.3	$ 3,420.3	$ (42.3)	$ (709.4)	$ (1,065.7)	$ 23.7