Corporate Investments and Funds Held For Clients (Classification Of Corporate Investments On The Consolidated Balance Sheets) (Details) - USD ($) $ in Millions	Sep. 30, 2021	Jun. 30, 2021	Sep. 30, 2020
Corporate Investments And Funds Held For Clients [Abstract]
Cash and cash equivalents	$ 1,602.1	$ 2,575.2	$ 1,613.1
Short-term marketable securities	74.3	10.4
Long-term marketable securities	0.0	23.5
Total corporate investments	$ 1,676.4	$ 2,609.1

Corporate Investments and Funds Held for Clients [Abstract]

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Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

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Sum of the carrying amounts as of the balance sheet date of all investments.

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Amount of investment in marketable security, classified as current.

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Amount of investment in marketable security, classified as noncurrent.

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