Defined benefit plan maximum effect on postretirement expense and benefit obligation from one percentage point increase decrease in assumed health care trend rate.

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- Definition

Postretirement Benefit Plans [Line Items]

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- Definition

The pretax net amount of gains and losses that are not yet recognized as a component of net periodic benefit cost, and that are recognized as increases or decreases in other comprehensive income as they arise. Gains and losses are due to changes in the value of either the benefit obligation or the plan assets resulting from experience different from that assumed or from a change in an actuarial assumption, or the consequence of a decision to temporarily deviate from the substantive plan.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 132R

-Paragraph 5

-Subparagraph i

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 158

-Paragraph 7

-Subparagraph c

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (j)

-URI http://asc.fasb.org/extlink&oid=6962843&loc=d3e1928-114920

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- Definition

The aggregate amount in accumulated other comprehensive income expected to be recognized as a component of net periodic benefit cost over the fiscal year that follows the most recent annual statement of financial position presented, including the net gain (loss), net prior service cost or credit, and net transition asset or obligation.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 132R

-Paragraph 5

-Subparagraph s

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 158

-Paragraph 7

-Subparagraph d

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (s)

-URI http://asc.fasb.org/extlink&oid=6962843&loc=d3e1928-114920

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- Definition

The interest rate used to adjust for the time value of money for the plan.

+ References

+ Details

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- Definition

The amount of the aggregate benefits expected to be paid in the five fiscal years thereafter (the aggregate amount of benefits expected to be paid in years 6 through 10 after the date of the latest statement of financial position).

+ References

+ Details

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- Definition

The amount of the benefits expected to be paid in Year 5.

+ References

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- Definition

The amount of the benefits expected to be paid in Year 4.

+ References

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- Definition

The amount of the benefits expected to be paid in Year 1.

+ References

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- Definition

The amount of the benefits expected to be paid in Year 3.

+ References

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- Definition

The amount of the benefits expected to be paid in Year 2.

+ References

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- Definition

The assumed health care cost trend rate for the next year used to measure the expected cost of benefits covered by the plan (gross eligible charges). This is based upon the annual rate of change in the cost of health care benefits currently provided by the postretirement benefit plan, due to factors other than changes in the composition of the plan population by age and dependency status.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 132R

-Paragraph 5

-Subparagraph l

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Health Care Cost Trend Rate

-URI http://asc.fasb.org/extlink&oid=6514820

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (l)

-URI http://asc.fasb.org/extlink&oid=6962843&loc=d3e1928-114920

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- Definition

The ultimate trend rate for health care costs.

+ References

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- Definition

The year when the ultimate health care cost trend rate is expected to be reached.

+ References

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Postretirement Plans (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2009
Postretirement Benefit Plans [Line Items]
Deferred actuarial gains in accumulated other comprehensive income	$ (1,899)
Gains that will be amortized into earnings in 2012	(184)
Postretirement Plans [Member]
Postretirement Benefit Plans [Line Items]
Deferred actuarial gains in accumulated other comprehensive income	84
Gains that will be amortized into earnings in 2012	10
Discount rates used in measuring benefit obligations	4.25%	4.25%	5.00%
Ultimate Healthcare Cost Trend Rate	8.00%	8.00%
Effect on postretirement expense and benefit obligation from one-percentage-point increase or decrease in assumed health care trend rate	5.00%
Health care cost trend rate, year	2018	2017
Future health care benefit payments in 2012	37
Future health care benefit payments in 2013	37
Future health care benefit payments in 2014	36
Future health care benefit payments in 2015	36
Future health care benefit payments in 2016	34
Total future health care benefit payments over the five years 2017 through 2021	$ 156
Postretirement Plans [Member] \| 2017 [Member]
Postretirement Benefit Plans [Line Items]
Health care cost trend rate		5.00%
Postretirement Plans [Member] \| 2018 [Member]
Postretirement Benefit Plans [Line Items]
Health care cost trend rate	5.00%