Segment Reporting (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
Dec. 31, 2012	Dec. 31, 2011
Segment Reporting Information [Line Items]
Net sales	$ 5,553	$ 5,309
Segment Earnings	673	553
Differences in accounting methods	50	49
Corporate and other	(123)	(129)
Intersegment sales	(144)	(132)
Interest expense	(54)	(58)
Change in stock compensation expense	22
Number of active performance share plans	2
Charge for the elimination of post-65 supplemental retiree medical benefits		19
Process Management [Member]
Segment Reporting Information [Line Items]
Segment Sales	1,896	1,527
Segment Earnings	333	190
Industrial Automation [Member]
Segment Reporting Information [Line Items]
Segment Sales	1,137	1,229
Segment Earnings	164	182
Intersegment sales	121	110
Network Power [Member]
Segment Reporting Information [Line Items]
Segment Sales	1,459	1,495
Segment Earnings	105	122
Climate Technologies [Member]
Segment Reporting Information [Line Items]
Segment Sales	752	733
Segment Earnings	101	100
Commercial & Residential Solutions [Member]
Segment Reporting Information [Line Items]
Segment Sales	453	457
Segment Earnings	97	97
Segment Total [Member]
Segment Reporting Information [Line Items]
Segment Sales	5,697	5,441
Segment Earnings	$ 800	$ 691

Increase (decrease) in stock compensation expense compared to prior period.

No definition available.

Name:	emr_ChangeInStockCompensationExpense
Namespace Prefix:	emr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Charge for the elimination of post-65 supplemental retiree medical benefits for a small group of active employees.

+ References

No definition available.

+ Details

Name:	emr_ChargeForEliminationOfPostSixtyFiveSupplementalRetireeMedicalBenefits
Namespace Prefix:	emr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Corporate and other costs

+ References

No definition available.

+ Details

Name:	emr_CorporateAndOtherCosts
Namespace Prefix:	emr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Differences in accounting methods

+ References

No definition available.

+ Details

Name:	emr_DifferencesInAccountingMethods
Namespace Prefix:	emr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Number of active performance share plans

+ References

No definition available.

+ Details

Name:	emr_NumberOfActivePerformanceSharePlans
Namespace Prefix:	emr_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

This element represents the income or loss from continuing operations attributable to the economic entity which may also be defined as revenue less expenses from ongoing operations, after income or loss from equity method investments, but before income taxes, extraordinary items, and noncontrolling interest.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 10

-Article 5

+ Details

Name:	us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The net amount of nonoperating interest income (expense).

+ References

No definition available.

+ Details

Name:	us-gaap_InterestIncomeExpenseNonoperatingNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of revenue from transactions with other operating segments of the same entity.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 131

-Paragraph 27

-Subparagraph b

-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_RevenuesFromTransactionsWithOtherOperatingSegmentsOfSameEntity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Total revenue from sale of goods and services rendered during the reporting period, in the normal course of business, reduced by sales returns and allowances, and sales discounts.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1)

-URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Article 5

+ Details

Name:	us-gaap_SalesRevenueNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	us-gaap_SegmentReportingInformationLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of total revenue for the reportable segments, including revenue from external customers, transactions with other operating segments of the same entity, and (gross) interest revenue. All considered to be "operating revenue" for purposes of the taxonomy.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 280

-SubTopic 10

-Section 50

-Paragraph 22

-Subparagraph (a),(b),(c)

-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8736-108599

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 131

-Paragraph 27

-Subparagraph a, b, 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.

+ Details

Name:	us-gaap_SegmentReportingInformationRevenue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration