Pensions and Other Postretirement Benefits (Tables)

6 Months Ended

Oct. 31, 2015

Pensions and Other Postretirement Benefits [Abstract]

Net periodic benefit cost

	Three Months Ended October 31,
	Defined Benefit Pension Plans				Other Postretirement Benefits
	2015		2014		2015		2014
Service cost	$	4.4	$	1.9	$	0.5	$	0.5
Interest cost		6.9		5.7		0.7		0.6
Expected return on plan assets		(8.3)		(6.2)		—		—
Recognized net actuarial loss (gain)		2.7		2.5		(0.1)		—
Prior service cost (credit)		0.2		0.3		(0.2)		(0.3)
Curtailment gain		(0.8)		—		(0.1)		—
Net periodic benefit cost	$	5.1	$	4.2	$	0.8	$	0.8
	Six Months Ended October 31,
	Defined Benefit Pension Plans				Other Postretirement Benefits
	2015		2014		2015		2014
Service cost	$	9.1	$	3.9	$	1.1	$	1.1
Interest cost		13.9		11.4		1.4		1.2
Expected return on plan assets		(16.7)		(12.5)		—		—
Recognized net actuarial loss (gain)		5.4		5.0		(0.1)		—
Prior service cost (credit)		0.4		0.5		(0.5)		(0.6)
Curtailment gain		(4.5)		—		(0.1)		—
Net periodic benefit cost	$	7.6	$	8.3	$	1.8	$	1.7