Summary of Significant Accounting Policies (Details) - USD ($) $ in Millions	3 Months Ended
	Oct. 31, 2018	Oct. 31, 2017
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Decrease in operating income	$ (98.7)	$ (89.1)
Increase in other income, net	$ 1.9	0.8
Accounting Standards Update 2017-07
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Decrease in operating income		1.6
Increase in other income, net		$ 1.6