Income Taxes - Effective Income Tax Rate Reconciliation (Details) - USD ($) $ in Millions	12 Months Ended
Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2019
Income tax reconciliation
Provision for income taxes at U.S. statutory rate	$ 146.2	$ 121.7	$ 127.5
Increase (decrease) in Provision for income taxes from:
State taxes, net of federal tax	15.2	11.3	12.0
Foreign tax differential	4.8	3.2	3.8
Valuation allowances	1.0	2.4	0.4
Stock-based compensation - excess tax benefits (“ETB”)	(16.9)	(15.6)	(19.3)
Tax Act Items	0.0	0.0	(0.5)
Other	(1.6)	(5.9)	1.3
Total Provision for income taxes	$ 148.7	$ 117.0	$ 125.2
Tax rate reconciliation (percent)
Provision for income taxes at U.S. statutory rate	21.00%	21.00%	21.00%
Increase (decrease) in Provision for income taxes from:
State taxes, net of federal tax	2.20%	1.90%	2.00%
Foreign tax differential	0.70%	0.60%	0.60%
Valuation allowances	0.10%	0.40%	0.10%
Stock-based compensation - excess tax benefits (“ETB”)	(2.40%)	(2.70%)	(3.20%)
Tax Act Items	0	0	(0.001)
Other	(0.20%)	(1.00%)	0.20%
Total Provision for income taxes	21.40%	20.20%	20.60%

Effective Income Tax Rate Reconciliation, Increase (Decrease) In Provision For Income Taxes [Abstract]

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Effective Income Tax Reconciliation, Increase (Decrease) In Provision For Income Taxes [Abstract]

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Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations applicable to statutory income tax expense (benefit) outside of the country of domicile.

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