Pension and Employee Benefit Plans, Cost Components of Pension Plans (Details) - USD ($) $ in Millions		12 Months Ended
		Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Components of net periodic benefit cost [Abstract]
Net periodic benefit cost	[1]	$ 3.0	$ 2.9	$ 3.3
Other changes in benefit obligation recognized in other comprehensive income (loss) [Abstract]
Amortization of net actuarial loss	[2]	5.8	5.4
Pension Plans [Member]
Components of net periodic benefit cost [Abstract]
Service cost		0.4	0.5	0.5
Interest cost		9.1	9.6	9.9
Expected return on plan assets		(12.0)	(12.3)	(11.9)
Amortization of net actuarial loss		6.0	5.6	5.6
Settlements	[3]	0.2	0.2	0.3
Curtailment gain	[3]	0.0	0.0	(0.3)
Net periodic benefit cost		3.7	3.6	4.1
Other changes in benefit obligation recognized in other comprehensive income (loss) [Abstract]
Net actuarial loss		(38.7)	(7.7)	(5.8)
Amortization of net actuarial loss		6.2	5.8	5.9
Total recognized in other comprehensive income (loss)		(32.5)	(1.9)	0.1
Reversal of amortization items [Abstract]
Estimated net actuarial loss that will be amortized		(6.9)
Pension Plans [Member] | Non-U.S Plans [Member] | Maximum [Member]
Components of net periodic benefit cost [Abstract]
Amortization of net actuarial loss		1.0	$ 1.0	$ 1.0
Reversal of amortization items [Abstract]
Estimated amortization in next fiscal year		$ 1.0

[1] Net periodic benefit cost for the Company’s pension and postretirement plans is exclusive of service cost.

[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 18 for additional information about the Company’s pension plans.

[3] The settlement charges and curtailment gain resulted from activity associated with the Company’s non-U.S. pension plans.