Retirement Benefits (Details 4)	12 Months Ended
Sep. 30, 2011	Sep. 30, 2010
Asset Allocation
Equity Securities, Minimum	30.00%
Equity Securities, Maximum	65.00%
Equity Securities, Target Allocation	55.00%
Equity Securities, as of the balance sheet date	54.00%	56.00%
Debt Securities, Minimum	35.00%
Debt Securities, Maximum	50.00%
Debt Securities, Target Allocation	41.00%
Debt Securities, as of the balance sheet date	41.00%	40.00%
Other, Minimum	0.00%
Other, Maximum	25.00%
Other, Target Allocation	4.00%
Other, as of the balance sheet date	5.00%	4.00%

The percentage of the fair value of debt securities to the fair value of total plan assets held as of the measurement date.

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The percentage of the fair value of equity securities to the fair value of total plan assets held as of the measurement date.

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The percentage of the fair value of investments other than debt securities, equity securities, and real estate to the fair value of total plan assets held as of the measurement date.

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Target allocation percentage of investments in debt securities to total plan assets presented on a weighted-average basis as of the measurement date of the latest statement of financial position.

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Target allocation minimum percentage of investments in debt securities to total plan assets presented on a weighted-average basis as of the measurement date of the latest statement of financial position.

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