Income Taxes (Components of Deferred Income Tax Assets and Liabilities) (Details) - USD ($) $ in Millions	Jun. 30, 2023	Jun. 30, 2022
Deferred tax assets:
Accrued expenses not currently deductible	$ 209.5	$ 212.1
Stock-based compensation expense	48.8	43.5
Foreign tax credits	13.3	5.9
Fixed and intangible assets	108.2	0.0
Net operating losses	37.5	34.1
Prepaid royalty	18.0	33.7
Unrealized investment losses, net	519.5	407.2
Other	39.9	38.3
Deferred tax assets, gross	994.7	774.8
Less: valuation allowances	(18.6)	(18.9)
Deferred tax assets, net	976.1	755.9
Deferred tax liabilities:
Deferred revenue	578.1	529.9
Fixed and intangible assets	0.0	6.5
Prepaid expenses	78.9	94.8
Prepaid retirement benefits	30.8	4.6
Tax on unrepatriated earnings	10.1	11.5
Other	20.7	18.2
Deferred tax liabilities	718.6	665.5
Net deferred tax (assets)/liabilities	$ (257.5)	$ (90.4)