Earnings Per Share (Tables)

6 Months Ended

Mar. 31, 2014

Earnings Per Share [Abstract]

Numerator and denominator used to compute basic and diluted earnings per share

	Three Months Ended March 31,				Six Months Ended March 31,
	2014		2013		2014		2013
	(In millions)
Numerator:
Net income	$	131.0	$	111.0	$	254.1	$	177.3
Effect of dilutive securities:
Interest and amortization of issuance costs associated with convertible senior notes, net of tax	6.9		5.8		13.7		11.5
Numerator for diluted earnings per share after assumed conversions	$	137.9	$	116.8	$	267.8	$	188.8
Denominator:
Denominator for basic earnings per share — weighted average common shares	324.3		321.7		323.7		321.4
Effect of dilutive securities:
Employee stock awards	3.4		5.1		3.1		4.7
Convertible senior notes	38.6		38.6		38.6		38.6
Denominator for diluted earnings per share — adjusted weighted average common shares	366.3		365.4		365.4		364.7