Share-Based Compensation (Schedule of Total Share-Based Compensation Expense by Type of Award) (Details) - USD ($) $ in Millions	3 Months Ended
	Sep. 30, 2025	Sep. 30, 2024
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation	$ 30.0	$ 30.0
Restricted Share Unit
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation	18.0	19.0
Performance Share Unit
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation	12.0	$ 11.0
GIA Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation	$ 63.0