CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (PARENTHETICAL) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Comprehensive Income [Abstract]
Unrealized (losses) gains on revaluation of long-term intercompany balances, taxes	$ 0.0	$ 0.0	$ 0.0
Change in derivative losses on cash flow hedges, taxes	0.0	0.0	2.7
Amortization of net actuarial losses and prior service cost, taxes	0.6	0.8	10.9
Adjustments of net actuarial losses and prior service cost, taxes	(1.1)	2.1	7.1
Other comprehensive income, equity method investment, taxes	$ 0.0	$ 0.0	$ 0.0