Postretirement Plans (Reconciliations Of Actuarial Present Value Of Accumulated Postretirement Benefit Obligations) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2010
Postretirement Benefit Plans [Line Items]
Benefit obligation, ending (recognized in balance sheet)	$ 818
Postretirement Plans [Member]
Postretirement Benefit Plans [Line Items]
Benefit obligation, beginning	392	417
Service cost	2	3	5
Interest cost	16	17	24
Actuarial (gain) loss	(10)	(25)
Benefits paid	(17)	(20)
Plan amendments	(16)	0
Benefit obligation, ending (recognized in balance sheet)	$ 367	$ 392	$ 417

The amount of payments made for which participants are entitled under a pension plan, including pension benefits, death benefits, and benefits due on termination of employment. Also includes payments made under a postretirement benefit plan, including prescription drug benefits, health care benefits, life insurance benefits, and legal, educational and advisory services. This item represents a periodic decrease to the plan obligations and a decrease to plan assets.

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-Publisher FASB

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-Publisher FASB

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Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Postretirement Benefits

-URI http://asc.fasb.org/extlink&oid=6521376

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-Glossary Benefits

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+ Details

- Definition

The increase in a defined benefit pension plan's projected benefit obligation or a defined benefit postretirement plan's accumulated postretirement benefit obligation due to the passage of time.

+ References+ Details

- Definition

The amount of increase or decrease due to a change in the terms of an existing plan or the initiation of a new plan. A plan amendment may increase or decrease benefits, including those attributed to years of service already rendered.

+ References

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+ Details

- Definition

The actuarial present value of benefits attributed by the pension benefit formula to services rendered by employees during the period. The portion of the expected postretirement benefit obligation attributed to employee service during the period. The service cost component is a portion of the benefit obligation and is unaffected by the funded status of the plan.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

-Glossary Service Cost (Component of Net Periodic Pension Cost)

-URI http://asc.fasb.org/extlink&oid=6525008

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+ Details