Pension and Other Postretirement Benefits

6 Months Ended

Oct. 31, 2011

Pension and Other Postretirement Benefits [Abstract]

Pension and Other Postretirement Benefits

7. Pension and Other Postretirement Benefits

The following table shows the components of the pension and other postretirement benefit expense recognized for our U.S. benefit plans during the periods covered by this report. Information about similar international plans is not presented due to immateriality.

	Three Months Ended October 31,						Six Months Ended October 31,
(Dollars in millions)	2010			2011			2010			2011
Pension Benefits:
Service cost	$	3.9		$	4.0		$	7.8		$	8.0
Interest cost		8.3			8.5			16.7			17.0
Expected return on plan assets		(9.1	)		(10.0	)		(18.1	)		(20.1	)
Amortization of:
Prior service cost		0.2			0.2			0.4			0.4
Net actuarial loss		4.7			4.8			9.3			9.7
Net expense	$	8.0		$	7.5		$	16.1		$	15.0
Other Postretirement Benefits:
Service cost	$	0.3		$	0.4		$	0.6		$	0.7
Interest cost		0.8			0.7			1.6			1.5
Amortization of:
Prior service cost		—			0.2			—			0.3
Net actuarial loss		—			—			0.1			—
Net expense	$	1.1		$	1.3		$	2.3		$	2.5