Business Segment Information (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	6 Months Ended
Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2015	Mar. 31, 2014
Segment Reporting Information [Line Items]
Net sales	$ 5,400us-gaap_SalesRevenueNet	$ 5,812us-gaap_SalesRevenueNet	$ 10,987us-gaap_SalesRevenueNet	$ 11,418us-gaap_SalesRevenueNet
Earnings before income taxes	1,604	817	2,369	1,460
Eliminations/Interest	(40)	(47)	(86)	(101)
Gain on sale of business	932us-gaap_GainLossOnSaleOfBusiness	0us-gaap_GainLossOnSaleOfBusiness	932us-gaap_GainLossOnSaleOfBusiness	0us-gaap_GainLossOnSaleOfBusiness
Increase (decrease) in incentive stock compensation expense	(19)		(46)
Increase (decrease) in income (loss) from equity method investment	(34)
Increase (decrease) in pretax charitable contributions			(30)
Increase (decrease) in inventory costs (purchase accounting)			(21)
Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales	5,586	6,012	11,336	11,757
Earnings before income taxes	738	951	1,602	1,776
Operating Segments [Member] \| Process Management [Member]
Segment Reporting Information [Line Items]
Net sales	2,042	2,108	4,141	4,149
Earnings before income taxes	299	383	691	756
Operating Segments [Member] \| Industrial Automation [Member]
Segment Reporting Information [Line Items]
Net sales	1,034	1,232	2,186	2,381
Earnings before income taxes	144	187	308	349
Operating Segments [Member] \| Network Power [Member]
Segment Reporting Information [Line Items]
Net sales	1,063	1,171	2,182	2,474
Earnings before income taxes	34	96	113	179
Operating Segments [Member] \| Climate Technologies [Member]
Segment Reporting Information [Line Items]
Net sales	982	1,041	1,882	1,827
Earnings before income taxes	170	186	296	293
Operating Segments [Member] \| Commercial & Residential Solutions [Member]
Segment Reporting Information [Line Items]
Net sales	465	460	945	926
Earnings before income taxes	91	99	194	199
Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Differences in accounting methods	53	60	111	117
Corporate and other	853	(147)	742	(332)
Eliminations/Interest	(40)	(47)	(86)	(101)
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Net sales	(186)	(200)	(349)	(339)
Intersegment Eliminations [Member] \| Industrial Automation [Member]
Segment Reporting Information [Line Items]
Net sales	$ (167)	$ (182)	$ (312)	$ (298)

Corporate and other costs

No definition available.

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Differences in accounting methods

+ References

No definition available.

+ Details

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Namespace Prefix:	emr_
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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 income (loss) from equity method investment

+ References

No definition available.

+ Details

Name:	emr_Increasedecreaseinincomelossfromequitymethodinvestment
Namespace Prefix:	emr_
Data Type:	xbrli:monetaryItemType
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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
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- Definition

Increase (decrease) in pretax charitable contributions

+ References

No definition available.

+ Details

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- Definition

Gain (loss) from sale or disposal of an organization or integrated set of activities (for example, but not limited to, a partnership or corporation) engaged in providing a product or service in a commercial, industrial, or professional environment.

+ References

No definition available.

+ Details

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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 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

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Data Type:	xbrli:monetaryItemType
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- Definition

The net amount of nonoperating interest income (expense).

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
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- 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

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- Details

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