Earnings Per Share (Tables)

3 Months Ended

Jul. 31, 2011

Earnings Per Share [Abstract]

Basic and diluted earnings per share

	Three Months Ended
	July 31
(Dollars in millions, except per share amounts)	2010			2011
Basic and diluted net income	$	111.4		$	118.1
Income allocated to participating securities (restricted shares)		(0.1	)		—
Net income available to common stockholders	$	111.3		$	118.1
Share data (in thousands):
Basic average common shares outstanding		146,570			144,828
Dilutive effect of stock options, SSARs, RSUs, and DSUs		815			1,039
Diluted average common shares outstanding		147,385			145,867
Basic earnings per share	$	0.76		$	0.81
Diluted earnings per share	$	0.76		$	0.81