Earnings per Share (Tables)

12 Months Ended

Apr. 30, 2014

Earnings Per Share [Abstract]

Computation of earnings per common share, basic and diluted

	Year Ended April 30,
	2014		2013		2012
Net income	$	565.2	$	544.2	$	459.7
Net income allocated to participating securities		4.5		4.7		4.2
Net income allocated to common stockholders	$	560.7	$	539.5	$	455.5
Weighted-average common shares outstanding		103,504,121		107,881,519		112,212,677
Dilutive effect of stock options		14,346		23,256		49,616
Weighted-average common shares outstanding – assuming dilution		103,518,467		107,904,775		112,262,293
Net income per common share	$	5.42	$	5.00	$	4.06
Net income per common share – assuming dilution	$	5.42	$	5.00	$	4.06