CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2015
Other comprehensive income (loss):
Defined benefit plans, tax	$ 0.4	$ 1.7	$ 1.3	$ 14.3