Earnings Per Share (Tables)

12 Months Ended

Sep. 30, 2017

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:

	September 30,
	2017		2016		2015
(In millions, except per share data)
Numerator
Net Income Attributable to Versum	$	193.0	$	212.0	$	184.1
Denominator
Weighted average number of common shares - Basic	108.7		108.7		108.7
Effect of dilutive securities
Employee stock option and other award plans	0.7		—		—
Weighted average number of common shares - Diluted	109.4		108.7		108.7
Earnings Per Common Share Attributable to Versum
Net Income Attributable to Versum - Basic	$	1.78	$	1.95	$	1.69
Net Income Attributable to Versum - Diluted	1.76		1.95		1.69