CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Comprehensive income:
Net income	$ 107.0	$ 113.2
Derivative instruments:
Reclassification of losses to net income, net of tax of $0.1	0.2	0.2
Total other comprehensive income	0.2	0.2
Total comprehensive income	$ 107.2	$ 113.4