Unaudited Condensed Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	3 Months Ended			6 Months Ended	9 Months Ended
	Sep. 30, 2017	Apr. 01, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Successor
Reclassification for realized losses on cash flow hedges included in net income (loss), tax provision	$ 0.0			$ 0.0
Postretirement plans and workers' compensation obligations, tax provision	$ 0.0			$ 0.0
Predecessor
Reclassification for realized losses on cash flow hedges included in net income (loss), tax provision		$ 9.1	$ 17.6		$ 69.9
Postretirement plans and workers' compensation obligations, tax provision		$ 2.5	$ 2.1		$ 6.3