Earnings Per Share (Tables)

12 Months Ended

Sep. 30, 2018

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,
	2018		2017		2016
(In millions, except per share data)
Numerator
Net Income Attributable to Versum	$	197.5	$	193.3	$	209.3
Denominator
Weighted average number of common shares - Basic	108.9		108.7		108.7
Effect of dilutive securities
Employee stock option and other award plans	0.9		0.7		—
Weighted average number of common shares - Diluted	109.8		109.4		108.7
Earnings Per Common Share Attributable to Versum
Net Income Attributable to Versum - Basic	$	1.81	$	1.78	$	1.93
Net Income Attributable to Versum - Diluted	1.80		1.77		1.93