Segment Reporting (Details) (USD $) In Millions	3 Months Ended	9 Months Ended
Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Segment Sales	$ 6,506	$ 5,611	$ 18,229	$ 15,697
Segment Earnings	1,097	970	2,904	2,476
Net sales	6,288	5,417	17,677	15,198
Earnings from continuing operations before income taxes	992	863	2,538	2,041
Joint venture ownership acquisition gain			15
Interest expense	(56)	(64)	(174)	(196)
Process Management [Member]
Segment Sales	1,789	1,511	4,984	4,321
Segment Earnings	366	311	952	768
Industrial Automation [Member]
Segment Sales	1,391	1,124	3,909	3,120
Segment Earnings	230	162	625	401
Intersegment sales	198	174	500	438
Network Power [Member]
Segment Sales	1,683	1,418	4,968	4,150
Segment Earnings	176	181	508	545
Climate Technologies [Member]
Segment Sales	1,171	1,106	2,995	2,798
Segment Earnings	229	222	539	498
Tools and Storage [Member]
Segment Sales	472	452	1,373	1,308
Segment Earnings	96	94	280	264
Differences in Accounting Methods [Member]
Differences in accounting methods	60	50	169	142
Corporate and Other [Member]
Segment Earnings	(109)	(93)	(361)	(381)
Change in stock compensation expense	13
Eliminations/Interest [Member]
Segment Sales	$ (218)	$ (194)	$ (552)	$ (499)

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

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

- Definition

Differences in accounting methods

+ Details

Name:	emr_DifferencesInAccountingMethods
Namespace Prefix:	emr
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Joint Venture Ownership Acquisition Gain (Loss)

+ Details

Name:	emr_JointVentureOwnershipAcquisitionGainLoss
Namespace Prefix:	emr
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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
-Article 5
-Section 03
-Paragraph 10

+ Details

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

- Definition

Sum of operating profit and nonoperating income or expense before Income or Loss from equity method investments, 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
-Article 4
-Section 08
-Paragraph h
-Subparagraph 1(i)

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(h)(1)(i))
-URI http://asc.fasb.org/extlink&oid=6881521&loc=d3e23780-122690

+ Details

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

- Definition

The net amount of nonoperating interest income (expense).

+ 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

+ 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 SEC
-Name Regulation S-X (SX)
-Number 210
-Article 5
-Section 03
-Paragraph 1

Reference 2: 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

+ Details

Name:	us-gaap_SalesRevenueNet
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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 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.

Reference 2: 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

+ Details

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