Investments in Affiliates (Schedule of Summarized Balance Sheet Information for Ibn Sina (National Methanol)) (Details) (National Methonal Company (Ibn Sina) [Member], USD $) In Millions, unless otherwise specified	Sep. 30, 2012	Sep. 30, 2011
National Methonal Company (Ibn Sina) [Member]
Schedule of Equity Method Investments [Line Items]
Current assets	$ 379	$ 350
Noncurrent assets	205	210
Current liabilities	172	162
Noncurrent liabilities	$ 56	$ 41

Investments in Affiliates (Schedule of Summarized Balance Sheet Information for Ibn Sina (National Methanol)) (Details) (National Methonal Company (Ibn Sina) [Member], USD $)
In Millions, unless otherwise specified

Sep. 30, 2012

Sep. 30, 2011

National Methonal Company (Ibn Sina) [Member]

Schedule of Equity Method Investments [Line Items]

Current assets

$ 379

$ 350

Noncurrent assets

205

210

Current liabilities

172

162

Noncurrent liabilities

$ 56

$ 41

- Definition

The amount of current assets reported by an equity method investment of the entity.

+ References

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

-Publisher AICPA

-Name Accounting Principles Board Opinion (APB)

-Number 18

-Paragraph 20

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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

-Topic 323

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

-Publisher FASB

-Name Accounting Standards Codification

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-SubTopic 10

-Section S99

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Reference 4: http://www.xbrl.org/2003/role/presentationRef

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Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 159

-Paragraph 18

-Subparagraph f

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 7: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

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Reference 8: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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-URI http://asc.fasb.org/extlink&oid=6382943&loc=d3e33912-111571

Reference 9: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph w

-Article 1

+ Details

- Definition

The amount of current liabilities reported by an equity method investment of the entity.

+ References

+ Details

- Definition

The amount of noncurrent assets reported by an equity method investment of the entity.

+ References

+ Details

- Definition

The amount of noncurrent liabilities reported by an equity method investment of the entity.

+ References

+ Details