Fair Value Measurements - Schedule of Fair Value of Assets and Liabilities Measured on a Recurring Basis (Details) - Measured on a recurring basis - USD ($) $ in Millions	Jun. 30, 2018	Jun. 30, 2017
Marketable securities
Derivative financial instruments	$ 35.2	$ 14.5
Total assets	38.1	17.9
Liabilities:
Derivative financial instruments	3.4	19.1
Level 2
Marketable securities
Derivative financial instruments	35.2	14.5
Total assets	38.1	17.9
Liabilities:
Derivative financial instruments	3.4	19.1
Municipal auction rate securities
Marketable securities
Municipal auction rate securities	2.9	3.4
Municipal auction rate securities \| Level 2
Marketable securities
Municipal auction rate securities	$ 2.9	$ 3.4

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

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Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

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