Pension and Employee Benefit Plans, Cost Components of Pension Plans (Details) - USD ($) $ in Millions		12 Months Ended
		Mar. 31, 2018		Mar. 31, 2017	Mar. 31, 2016
Components of net periodic benefit cost [Abstract]
Net periodic benefit cost	[1]	$ 3.3		$ 2.9	$ 44.6
Other changes in benefit obligation recognized in other comprehensive income (loss) [Abstract]
Amortization of net actuarial loss	[2]	(5.6)		(5.2)
Pension Plans [Member]
Components of net periodic benefit cost [Abstract]
Service cost		0.5		0.6	0.6
Interest cost		9.9		9.8	11.2
Expected return on plan assets		(11.9)		(12.3)	(14.9)
Amortization of net actuarial loss		5.6		5.6	6.4
Settlements		0.3		0.0	42.1	[3]
Curtailment gain		(0.3)	[4]	0.0	0.0
Net periodic benefit cost		4.1		3.7	45.4
Other changes in benefit obligation recognized in other comprehensive income (loss) [Abstract]
Net actuarial loss		(5.8)		(1.0)	(17.5)
Amortization of net actuarial loss		5.9		5.6	48.5	[3]
Total recognized in other comprehensive income (loss)		0.1		$ 4.6	$ 31.0
Reversal of amortization items [Abstract]
Estimated net actuarial loss that will be amortized		$ (5.6)

[1] Represents net periodic benefit cost, exclusive of service cost, for the Company's pension and postretirement plans.

[2] Amounts are included in the calculation of net periodic benefit cost for the Company's defined benefit plans, which include pension and other postretirement plans. See Note 16 for additional information about the Company's pension plans.

[3] During fiscal 2016, in connection with lump-sum payouts to pension plan participants, the Company recorded $42.1 million of settlement losses, which were previously recorded in accumulated other comprehensive loss.

[4] During the third quarter of fiscal 2018, the Company recorded a pension curtailment gain associated with the closure of a manufacturing facility in Austria (CIS segment). See Note 5 for additional information regarding the closure of this facility.