Other Financial Information (PPE) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Sep. 30, 2018
Property, Plant and Equipment [Abstract]
Property, plant and equipment, at cost	$ 8,451	$ 8,370
Less: Accumulated depreciation	4,900	4,808
Total	$ 3,551	$ 3,562

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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-Section 50
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- References

No definition available.

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- Definition

Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 1
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- Definition

Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(14))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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-URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229

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-Name Accounting Standards Codification
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