Business Segment Information (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Segment Reporting Information [Line Items]
Net sales	$ 5,587us-gaap_SalesRevenueNet	$ 5,606us-gaap_SalesRevenueNet
Earnings before income taxes	765	643
Eliminations/Interest	(46)	(54)
Increase (decrease) in incentive stock compensation expense	(27)
Increase (decrease) in inventory costs (purchase accounting)	(20)
Increase (decrease) in pretax charitable contributions	(30)
Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales	5,750	5,745
Earnings before income taxes	864	825
Operating Segments [Member] \| Process Management [Member]
Segment Reporting Information [Line Items]
Net sales	2,099	2,041
Earnings before income taxes	392	373
Operating Segments [Member] \| Industrial Automation [Member]
Segment Reporting Information [Line Items]
Net sales	1,152	1,149
Earnings before income taxes	164	162
Operating Segments [Member] \| Network Power [Member]
Segment Reporting Information [Line Items]
Net sales	1,119	1,303
Earnings before income taxes	79	83
Operating Segments [Member] \| Climate Technologies [Member]
Segment Reporting Information [Line Items]
Net sales	900	786
Earnings before income taxes	126	107
Operating Segments [Member] \| Commercial & Residential Solutions [Member]
Segment Reporting Information [Line Items]
Net sales	480	466
Earnings before income taxes	103	100
Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Differences in accounting methods	58	57
Corporate and other	(111)	(185)
Eliminations/Interest	(46)	(54)
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Net sales	(163)	(139)
Intersegment Eliminations [Member] \| Industrial Automation [Member]
Segment Reporting Information [Line Items]
Net sales	$ (145)	$ (116)

Corporate and other costs

No definition available.

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

Increase (decrease) in incentive stock compensation expense.

+ References

No definition available.

+ Details

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

- Definition

Increase (decrease) in inventory costs (purchase accounting) versus prior period.

+ References

No definition available.

+ Details

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

- Definition

Increase (decrease) in pretax charitable contributions

+ References

No definition available.

+ Details

Name:	emr_IncreaseDecreaseinPretaxCharitableContributions
Namespace Prefix:	emr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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 FASB

-Name Accounting Standards Codification

-Topic 940

-SubTopic 20

-Section 25

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=35710027&loc=d3e41242-110953

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 3: 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

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=26872669&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

- Details

Name:	us-gaap_ConsolidationItemsAxis=us-gaap_CorporateNonSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ConsolidationItemsAxis=us-gaap_IntersegmentEliminationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ConsolidationItemsAxis=us-gaap_OperatingSegmentsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: