Carrying amount of long-term convertible debt as of the balance sheet date, net of the amount due in the next twelve months or greater than the normal operating cycle, if longer. The debt is convertible into another form of financial instrument, typically the entity's common stock.

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The carrying amount of the equity component of convertible debt which may be settled in cash upon conversion.

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The price per share of the conversion feature embedded in the debt instrument.

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Face (par) amount of debt instrument at time of issuance.

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Contractual interest rate for funds borrowed, under the debt agreement.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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The cash outflow from the repayment of a long-term debt instrument which can be exchanged for a specified amount of another security, typically the entity's common stock, at the option of the issuer or the holder.

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The cash outflow during the period from the repayment of aggregate short-term and long-term debt. Excludes payment of capital lease obligations.

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Number of shares that have been repurchased and retired during the period.

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Equity impact of the value of stock that has been repurchased during the period and has not been retired and is not held in treasury. Some state laws may mandate the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

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Debt and Credit Facilities 1.25% Convertible Debentures due 2025 (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	1 Months Ended	3 Months Ended			6 Months Ended	9 Months Ended		74 Months Ended
	Nov. 30, 2017	Jun. 30, 2019	Jun. 30, 2015	Dec. 31, 2014	Mar. 31, 2017	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Sep. 30, 2018	Mar. 13, 2017	Oct. 24, 2011
Debt Instrument [Line Items]
Debt Instrument, Face Amount		$ 2,137.0				$ 2,137.0		$ 2,137.0	$ 2,437.0
Stock Repurchased and Retired During Period, Shares		1.7				7.8	8.1	63.9
Stock Repurchased During Period, Value		$ 29.6				$ 120.9	$ 112.0	$ 1,063.6
Convertible Debentures 1.25% Due 2025 [Member]
Debt Instrument [Line Items]
Convertible Debt, Noncurrent										$ 252.1
Debt Instrument, Face Amount										$ 350.0
Debt Instrument, Interest Rate, Stated Percentage		1.25%				1.25%		1.25%	1.25%	1.25%
Debt Instrument, Convertible, Carrying Amount of Equity Component										$ 97.9
Debt Instrument, Convertible, Conversion Price										$ 22.22
Convertible Debentures Two Point Seven Five Percent Due November One Twenty Thirty One [Member]
Debt Instrument [Line Items]
Convertible Debt, Noncurrent											$ 533.6
Debt Instrument, Face Amount		$ 46.6				$ 46.6		$ 46.6			$ 690.0
Debt Instrument, Interest Rate, Stated Percentage		2.75%				2.75%		2.75%	2.75%		2.75%
Repayments of Convertible Debt			$ 256.2	$ 38.3	$ 17.8
Repayments of Debt	$ 331.2
Debt Instrument, Convertible, Carrying Amount of Equity Component											$ 156.4
Debt Instrument, Convertible, Conversion Price											$ 32.30