Earnings Per Share (Tables)

6 Months Ended

Mar. 31, 2019

Earnings Per Share [Abstract]

Schedule of Earnings Per Share, Basic and Diluted

The following table sets forth the computation of basic and diluted earnings per share under the two-class method (in millions, except per share data):

	Three Months Ended				Six Months Ended
	March 31,				March 31,
	2019		2018		2019		2018
Numerator:
Net income attributable to common stockholders	$	160.4	$	223.2	$	299.5	$	1,358.3
Less: Distributed and undistributed income    available to participating securities		—		—		—		(0.2	)
Distributed and undistributed income available to    common stockholders	$	160.4	$	223.2	$	299.5	$	1,358.1
Denominator:
Basic weighted average shares outstanding		256.6		256.1		255.7		255.5
Effect of dilutive stock options and non-    participating securities		2.8		4.2		3.7		4.2
Diluted weighted average shares outstanding		259.4		260.3		259.4		259.7
Basic earnings per share attributable to common    stockholders	$	0.63	$	0.87	$	1.17	$	5.32
Diluted earnings per share attributable to common    stockholders	$	0.62	$	0.86	$	1.15	$	5.23