CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Statement of Comprehensive Income [Abstract]
Net income	$ 69.2	$ 50.3	$ 266.9	$ 230.3
Other comprehensive income:
Reclassification adjustment transferred to Net income from cash flow hedges	0.0	0.0	0.1	0.4
Pension and other postretirement benefit costs, net of tax	0.2	0.7	1.5	1.4
Total Comprehensive Income	$ 69.4	$ 51.0	$ 268.5	$ 232.1