Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	3 Months Ended			9 Months Ended		12 Months Ended
	Sep. 30, 2018	Mar. 31, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016
Cash flow from operating activities:
Net income (loss)	$ (218.7)		$ (29.4)	$ (416.6)	$ (106.5)
Adjustments to reconcile net income (loss) to cash flow used by operating activities:
Depreciation and amortization				194.7	185.4
Share-based compensation	6.9		8.1	27.2	23.1
Gain on sale of assets, net				(6.8)	(2.5)
Impairment of assets	109.3		0.0	199.3	3.1
Deferred income taxes				(52.8)	(36.3)
Other				(2.7)	(1.4)
Changes in certain assets and liabilities, net of the effects of acquisitions
Trade receivables				(20.6)	(57.5)
Inventories				(142.9)	(45.8)
Accounts payable				7.4	10.0
Income taxes				(6.8)	46.8
Prepaid and other current assets				(32.5)	(42.0)
Deferred revenue				(60.9)	(43.3)
Restructuring payments				37.9	57.8
Warranty liability				(28.3)	(25.0)
Certain other assets and liabilities				(5.5)	8.0
Net cash provided (used) by operating activities				(372.1)	(235.3)
Cash flow from investing activities:
Capital expenditures				(40.5)	(41.7)
Payment for acquisitions		$ (5.8)		(5.9)	(5.6)	$ (5.6)
Proceeds from maturities of short-term investments				275.0	249.5
Payments for purchases of short-term investments				(126.5)	(260.7)
Proceeds from sale of assets				10.8	14.6
Increase in certain other assets				(22.8)	(26.9)
Net cash provided (used) by investing activities				90.1	(70.8)
Cash flow from financing activities:
Dividends paid	0.0		(7.6)	(7.7)	(22.9)
Debt issuance costs				38.9	1.1
Revolving credit facility (repayments) borrowings, net				185.0	120.0
Other debt borrowings				706.0	381.0
Other debt repayments				(306.7)	(433.5)
Distributions and payments to noncontrolling interest holders				(337.8)	(16.3)
Issuance of common shares				0.0	0.3
Repurchase of common shares				(3.0)	(4.8)
Net cash provided (used) by financing activities				196.9	22.7
Effect of exchange rate changes on cash and cash equivalents				(14.4)	19.3
Increase (decrease) in cash, cash equivalents and restricted cash				(99.5)	(264.1)
Cash, cash equivalents and restricted cash at the beginning of the period	$ 443.7		$ 388.6	$ 443.7	$ 388.6	$ 543.2	$ 652.7