CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 42.5	$ 37.9	$ 226.3	$ 177.3
Other comprehensive income:
Reclassification adjustment transferred to Net income from cash flow hedges	0.3	0.2	0.7	1.0
Pension and other postretirement benefit costs, net of tax	0.5	(0.1)	2.9	1.4
Total Comprehensive Income	$ 43.3	$ 38.0	$ 229.9	$ 179.7