Fair Value Measurements Fair Value Measurements (Pre-tax Impact of Derivatives) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2020	Jan. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Pre-tax gains (losses) recognized in accumulated other comprehensive income (loss) - Net investment hedges	$ 0.6	$ 0.0	$ 1.4	$ 0.0
Pre-tax (gains) losses reclassified from accumulated other comprehensive income (loss) - Net investment hedges	0.0	0.0	0.0	0.0
Forward foreign currency exchange contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Pre-tax gains (losses) recognized in accumulated other comprehensive income (loss)	(0.6)	0.1	(1.3)	1.1
Pre-tax (gains) losses reclassified from accumulated other comprehensive income (loss)	$ 0.1	$ (0.1)	$ 2.0	$ (0.4)