Financial Instruments (Schedule of Interest Rate Swaps and Cross Currency Interest Rate Swaps) (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
Jun. 30, 2017	Sep. 30, 2016
Interest Rate Swaps Contracts [Member] \| Fair Value Hedges [Member] \| Designated as Hedging Instrument [Member]
Derivative [Line Items]
US$ Notional	$ 600.0	$ 600.0
Average Pay %	LIBOR	LIBOR
Average Receive %	2.28%	2.28%
Years Average Maturity	1 year 6 months	2 years 4 months
Cross Currency Interest Rate Swaps [Member] \| Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
US$ Notional	$ 51.2	$ 27.4
Average Pay %	3.38%	3.62%
Average Receive %	1.91%	0.81%
Years Average Maturity	1 year 8 months	1 year 10 months
Cross Currency Interest Rate Swaps [Member] \| Net Investment Hedges [Member] \| Designated as Hedging Instrument [Member]
Derivative [Line Items]
US$ Notional	$ 493.9	$ 517.7
Average Pay %	3.24%	3.24%
Average Receive %	2.39%	2.43%
Years Average Maturity	1 year 10 months	2 years 7 months
Cross Currency Interest Rate Swaps [Member] \| Cash Flow Hedges [Member] \| Designated as Hedging Instrument [Member]
Derivative [Line Items]
US$ Notional	$ 1,095.7	$ 1,088.9
Average Pay %	4.96%	4.77%
Average Receive %	2.78%	2.72%
Years Average Maturity	2 years 8 months	3 years 4 months

Average pay interest rate related to the group of interest rate derivatives

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- Definition

Average receive interest rate related to group of interest rate derivatives.

+ References

No definition available.

+ Details

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- Definition

The reference rate for the variable rate of the interest rate derivative, such as LIBOR or the US Treasury rate and the maturity of the reference rate used, such as three months or six months LIBOR.

+ References

No definition available.

+ Details

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- Definition

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

+ Details

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- Definition

Average remaining period until maturity of the derivative contract, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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- Definition

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.

+ References

No definition available.

+ Details

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- Details

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