Selected Quarterly Financial Data, Unaudited (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	1 Months Ended			3 Months Ended								12 Months Ended
	Feb. 28, 2018	Aug. 31, 2017	Feb. 28, 2017	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Total revenue				$ 885.7	$ 821.0	$ 844.7	$ 811.8	$ 823.0	$ 768.9	$ 766.3	$ 725.4	$ 3,363.2	$ 3,083.6	$ 2,883.4
Cost of revenues				341.4	301.3	315.9	296.7	314.9	290.8	278.9	280.0	1,255.3	1,164.6	1,106.3
Selling, general and administrative				181.7	169.7	173.9	171.6	167.7	158.8	145.9	140.7	696.9	613.1	577.0
Research and development				49.8	49.5	49.2	53.8	45.8	47.8	48.1	42.4	202.3	184.1	204.8
Restructuring and other				(171.0)	338.7	33.5	52.2	27.8	7.8	1.1	9.2	253.4	45.9	57.0
Depreciation, amortization and impairments				162.6	166.3	172.7	188.1	169.6	173.1	175.0	165.1	689.7	682.8	738.7
Operating income (loss)				321.2	(204.5)	99.5	49.4	97.2	90.6	117.3	88.0	265.6	393.1	130.6
Net (loss) income				$ 206.8	$ (351.6)	$ (5.8)	$ (201.8)	$ (43.1)	$ (59.3)	$ (39.1)	$ (100.8)	$ (352.4)	$ (242.3)	$ (353.7)
Basic net (loss) income per share (in dollars per share)				$ 2.25	$ (3.85)	$ (0.06)	$ (2.24)					$ (3.87)	$ (2.72)	$ (4.05)
Diluted net (loss) income per share (in dollars per share)				$ 2.21	$ (3.85)	$ (0.06)	$ (2.24)					$ (3.87)	$ (2.72)	$ (4.05)
Basic and diluted net loss per share (in dollars per share)								$ (0.48)	$ (0.66)	$ (0.44)	$ (1.14)
Weighted average number of shares used in per share calculations:
Basic shares (in shares)				91.8	91.4	91.0	90.1	89.7	89.6	89.1	88.2	91.1	89.1	87.3
Diluted shares (in shares)				93.4	91.4	91.0	90.1	89.7	89.6	89.1	88.2	91.1	89.1	87.3
Loss on debt financing transactions	$ 93.2	$ 8.4	$ 29.7									$ 93.2	$ 38.1	$ (25.2)
Gain (loss) on remeasurement of debt				$ 14.0	$ (4.0)	$ 34.5	$ (1.1)					43.4	0.0	$ 0.0
Loss contingency accrual				3.7				$ 4.7				$ 3.7	$ 4.7
Shuffle Tech Matter
Weighted average number of shares used in per share calculations:
Loss contingency accrual					$ 309.6
Reversal of legal reserve due to settlement				$ 183.1