CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) (Parenthetical) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016
Other comprehensive income (loss):
Defined benefit plans, tax	$ 0.4	$ 0.4	$ 1.3	$ 1.3
Cash flow hedges, tax	$ 0.2	$ 0.0	$ 0.2	$ 0.0