Acquisitions And Divestitures (Schedule Of Purchase Price Of Avocent And Chloride Allocated To Assets And Liabilities) (Details) (USD $) In Millions	12 Months Ended
Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2009
Business Acquisition [Line Items]
Intangibles	$ 75	$ 1,166	$ 365
Goodwill	125	1,633	541
Debt assumed		169	230
Cash paid, net of cash acquired	232	2,843	776
Avocent And Chloride [Member]
Business Acquisition [Line Items]
Accounts receivable		197
Inventory		155
Property, plant & equipment and other assets		148
Intangibles		1,071
Goodwill		1,509
Assets held for sale, including deferred taxes		278
Total assets		3,358
Accounts payable and accrued expenses		183
Debt assumed		165
Deferred taxes and other liabilities		395
Cash paid, net of cash acquired		$ 2,615

Business acquisition purchase price allocation current assets asset held for sale including deferred taxes.

Name:	emr_BusinessAcquisitionPurchasePriceAllocationCurrentAssetsAssetHeldForSaleIncludingDeferredTaxes
Namespace Prefix:	emr
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Business acquisition purchase price allocation current liabilities accounts payable and accrued expenses.

+ Details

Name:	emr_BusinessAcquisitionPurchasePriceAllocationCurrentLiabilitiesAccountsPayableAndAccruedExpenses
Namespace Prefix:	emr
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Business acquisition purchase price allocation property plant and equipment and other assets.

+ Details

Name:	emr_BusinessAcquisitionPurchasePriceAllocationPropertyPlantAndEquipmentAndOtherAssets
Namespace Prefix:	emr
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ Details

Name:	us-gaap_BusinessAcquisitionLineItems
Namespace Prefix:	us-gaap
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of acquisition cost of a business combination allocated to an identifiable intangible asset that will be amortized.

+ References

+ Details

Name:	us-gaap_BusinessAcquisitionPurchasePriceAllocationAmortizableIntangibleAssets
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The amount of acquisition cost of a business combination allocated to assets acquired.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141

-Paragraph 37

-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.

+ Details

Name:	us-gaap_BusinessAcquisitionPurchasePriceAllocationAssetsAcquired
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The amount of acquisition cost of a business combination allocated to inventory, including finished goods, work-in-process, and raw materials.

+ References

+ Details

Name:	us-gaap_BusinessAcquisitionPurchasePriceAllocationCurrentAssetsInventory
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The amount of acquisition cost of a business combination allocated to receivables.

+ References

+ Details

Name:	us-gaap_BusinessAcquisitionPurchasePriceAllocationCurrentAssetsReceivables
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of goodwill arising from a business combination, which is the excess of the cost of the acquired entity over the amounts assigned to assets acquired and liabilities assumed.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141

-Paragraph 52

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141

-Paragraph 53

-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.

+ Details

Name:	us-gaap_BusinessAcquisitionPurchasePriceAllocationGoodwillAmount
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The amount of acquisition cost of a business combination allocated to the noncurrent portion of the long-term debt assumed from the acquired entity.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141

-Paragraph 51

-Subparagraph e

-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 Emerging Issues Task Force (EITF)

-Number 98-1

-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 Statement of Financial Accounting Standard (FAS)

-Number 141

-Paragraph 37

-Subparagraph g

-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.

+ Details

Name:	us-gaap_BusinessAcquisitionPurchasePriceAllocationNoncurrentLiabilitiesLongTermDebt
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The amount of acquisition cost of a business combination allocated to other noncurrent liabilities of the acquired entity.

+ References

+ Details

Name:	us-gaap_BusinessAcquisitionPurchasePriceAllocationOtherNoncurrentLiabilities
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The cash outflow associated with the acquisition of a business, net of the cash acquired from the purchase.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 15, 17

-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 Investing Activities

-URI http://asc.fasb.org/extlink&oid=6516133

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 13

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3213-108585

+ Details

Name:	us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration