Derivatives and Fair Value Measurements - Gains and Losses on Hedging Derivatives (Details) - Designated as Hedging Instrument - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Successor
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) realized in income on derivatives	$ (2.4)
Unrealized gain (loss) recognized in income on non- designated derivatives	(1.8)
Total loss recognized in income	(4.2)
Successor | Commodity swap contracts | Reorganization items, net
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) realized in income on derivatives	(2.4)
Unrealized gain (loss) recognized in income on non- designated derivatives	(1.8)
Total loss recognized in income	$ (4.2)
Predecessor
Derivative Instruments, Gain (Loss) [Line Items]
Loss reclassified from other comprehensive loss into income		$ (27.6)
Total loss recognized in income		(27.6)
Predecessor | Commodity swap contracts | Operating costs and expenses
Derivative Instruments, Gain (Loss) [Line Items]
Loss reclassified from other comprehensive loss into income		(11.0)
Total loss recognized in income		(11.0)
Predecessor | Foreign currency cash flow hedge contracts | Operating costs and expenses
Derivative Instruments, Gain (Loss) [Line Items]
Loss reclassified from other comprehensive loss into income		(16.6)
Total loss recognized in income		$ (16.6)