CONSOLIDATED COMPREHENSIVE INCOME STATEMENTS (Unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Statement of Comprehensive Income [Abstract]
Net Income	$ 54.7	$ 49.8	$ 153.8	$ 172.9
Other Comprehensive Income (Loss), net of tax
Translation adjustments, net	(4.6)	0.5	(5.4)	15.6
Pension activity, net of tax for the three and six months ended March 31, 2017 of $0 and $1.5, respectively	0.1	0.0	(5.6)	0.0
Total Other Comprehensive Income (Loss)	(4.5)	0.5	(11.0)	15.6
Comprehensive Income	50.2	50.3	142.8	188.5
Net Income Attributable to Non-controlling Interests	2.0	2.0	5.4	6.1
Other Comprehensive Income (Loss) Attributable to Non-controlling Interests	(0.2)	(0.6)	1.2	(0.1)
Comprehensive Income Attributable to Versum	$ 48.4	$ 48.9	$ 136.2	$ 182.5