Accumulated Other Comprehensive Income (Loss) - Reclassifications out of AOCI (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Income Statement [Abstract]
Interest expense	$ 23.1	$ 27.1
Benefit for income taxes	(17.5)	67.0
Net income (loss) attributable to parent	(90.4)	(36.8)
Reclassification out of Accumulated Other Comprehensive (Loss) Income
Income Statement [Abstract]
Net income (loss) attributable to parent	1.0	4.5
Unrecognized Gains (Losses) on Cash Flow Hedges | Reclassification out of Accumulated Other Comprehensive (Loss) Income
Income Statement [Abstract]
Interest expense	0.0	5.3
Benefit for income taxes	0.0	(1.3)
Net income (loss) attributable to parent	0.0	4.0
Pension and Other Postretirement Benefit Plans | Reclassification out of Accumulated Other Comprehensive (Loss) Income
Income Statement [Abstract]
Net periodic benefit cost	1.3	0.7
Benefit for income taxes	(0.3)	(0.2)
Net income (loss) attributable to parent	$ 1.0	$ 0.5