Share-Based Compensation (Tables)

3 Months Ended

Dec. 31, 2019

Share-based Payment Arrangement [Abstract]

Schedule of Recognized Share-Based Compensation Cost

Share-based compensation cost recognized on the consolidated income statements is summarized below:

	Three Months Ended
	31 December
	2019			2018
Before-tax share-based compensation cost		$15.4			$9.3
Income tax benefit	(3.7		)	(2.2		)
After-tax share-based compensation cost		$11.7			$7.1

Schedule of Assumptions for Fair Value of Market-Based Deferred Stock Units

The calculation of the fair value of market-based deferred stock units used the following assumptions:

Expected volatility	17.8	%
Risk-free interest rate	1.6	%
Expected dividend yield	2.4	%