Share-Based Compensation (Tables)

6 Months Ended

Mar. 31, 2023

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		Six Months Ended
	31 March		31 March
	2023	2022	2023	2022
Before-tax share-based compensation cost	$15.5	$10.5	$32.4	$27.3
Income tax benefit	(3.9)	(2.6)	(7.9)	(6.7)
After-tax share-based compensation cost	$11.6	$7.9	$24.5	$20.6

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	32.5	%
Risk-free interest rate	4.0	%
Expected dividend yield	2.4	%