Assets, usually stocks, bonds, and other investments, that have been segregated and restricted (usually in a trust) to provide benefits, at their fair value as of the measurement date. Plan assets include amounts contributed by the employer (and by employees for a contributory plan) and amounts earned from investing the contributions, less benefits paid. If a plan has liabilities other than for benefits, those non-benefit obligations may be considered as reductions of plan assets.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

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Target allocation of investments of this type to total plan assets presented on a weighted average basis.

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Target allocation maximum percentage of investments of this type to total plan assets presented on a weighted average basis.

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Percentage of fair value of investments (categorized by debt securities, equity securities, real estate and other plan assets) to the fair value of plan assets held.

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Employee Retirement Plans - Pension Plans (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Pension Benefit
Defined Benefit Plans and Other Postretirement Benefit Plans
Actual Pension Plan	100.00%	100.00%
Target Asset Allocation	100.00%
Pension and Other Postretirement Benefit Contributions, Fair Value	$ 459.4	$ 415.3	$ 369.9
Pension Benefit \| Equity Securities
Defined Benefit Plans and Other Postretirement Benefit Plans
Actual Pension Plan	66.90%	68.60%
Target Asset Allocation	65.00%
Permitted Range - Minimum	60.00%
Permitted Range - Maximum	70.00%
Pension Benefit \| Domestic Equity Investments
Defined Benefit Plans and Other Postretirement Benefit Plans
Actual Pension Plan	55.60%	57.50%
Target Asset Allocation	52.50%
Permitted Range - Minimum	40.00%
Permitted Range - Maximum	65.00%
Pension Benefit \| International Index Mutual Funds
Defined Benefit Plans and Other Postretirement Benefit Plans
Actual Pension Plan	11.30%	11.10%
Target Asset Allocation	12.50%
Permitted Range - Minimum	7.50%
Permitted Range - Maximum	17.50%
Pension Benefit \| Fixed Income Funds And Cash Equivalents
Defined Benefit Plans and Other Postretirement Benefit Plans
Actual Pension Plan	33.10%	31.40%
Target Asset Allocation	35.00%
Permitted Range - Minimum	30.00%
Permitted Range - Maximum	40.00%
VEBA Trust
Defined Benefit Plans and Other Postretirement Benefit Plans
Actual Pension Plan	100.00%	100.00%
Target Asset Allocation	100.00%
Pension and Other Postretirement Benefit Contributions, Fair Value	12.8	11.7
VEBA Trust \| Domestic Equity Investments
Defined Benefit Plans and Other Postretirement Benefit Plans
Actual Pension Plan	67.90%	65.60%
Target Asset Allocation	65.00%
Permitted Range - Minimum	60.00%
Permitted Range - Maximum	70.00%
VEBA Trust \| Fixed Income Funds And Cash Equivalents
Defined Benefit Plans and Other Postretirement Benefit Plans
Actual Pension Plan	32.10%	34.40%
Target Asset Allocation	35.00%
Permitted Range - Minimum	30.00%
Permitted Range - Maximum	40.00%
Other Assets \| Supplemental defined contribution executive retirement plans [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans
Pension and Other Postretirement Benefit Contributions, Fair Value	$ 3.4	$ 3.4