Consolidated Statements of Comprehensive Income Parenthetical - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax	$ (5.9)	$ (3.8)	$ (3.0)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Tax	(3.5)	(0.8)	(0.4)
Other Comprehensive Income (Loss), Defined Benefit Plan, Adjustment for Settlement or Curtailment Gain (Loss), Tax	34.9	0.0	0.0
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, Tax	2.7	9.0	2.9
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, Tax	(0.3)	0.0	0.0
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, Tax	$ (1.3)	$ (1.1)	$ (1.1)