Other Postretirement Benefits (Plan Asset Allocations) (Details) (Other Postretirement Benefits [Member])	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Other Postretirement Benefits [Member]
Equity Securities, Target Allocation, Minimum	57.00%
Equity Securities, Target Allocation, Maximum	73.00%
Plan Assets, Equity Securities		62.00%	67.00%	66.00%
Debt Securities, Target Allocation, Minimum	26.00%
Debt Securities, Target Allocation, Maximum	44.00%
Plan Assets, Debt Securities		38.00%	33.00%	34.00%
Target Allocation Range, Total	100.00%
Plan Assets, Total		100.00%	100.00%	100.00%

Defined Benefit Plan, Target Allocation Percentage, total

No definition available.

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Namespace Prefix:	ed_
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- Definition

The percentage of the fair value of debt securities to the fair value of total plan assets held as of the measurement date.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 132R

-Paragraph 5

-Subparagraph d(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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 5

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=6962843&loc=d3e2446-114920

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (d)(1)

-URI http://asc.fasb.org/extlink&oid=6962843&loc=d3e1928-114920

+ Details

Name:	us-gaap_DefinedBenefitPlanDebtSecurities
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The percentage of the fair value of equity securities to the fair value of total plan assets held as of the measurement date.

+ References

+ Details

Name:	us-gaap_DefinedBenefitPlanEquitySecurities
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Target allocation maximum percentage of investments in debt securities to total plan assets presented on a weighted-average basis as of the measurement date of the latest statement of financial position.

+ References

No definition available.

+ Details

Name:	us-gaap_DefinedBenefitPlanTargetAllocationPercentageOfAssetsDebtSecuritiesRangeMaximum
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Target allocation minimum percentage of investments in debt securities to total plan assets presented on a weighted-average basis as of the measurement date of the latest statement of financial position.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 132R

-Paragraph 5

-Subparagraph d(2)

-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 715

-SubTopic 20

-Section 50

-Paragraph 5

-Subparagraph (c)(i)

-URI http://asc.fasb.org/extlink&oid=6962843&loc=d3e2446-114920

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (d)(i)

-URI http://asc.fasb.org/extlink&oid=6962843&loc=d3e1928-114920

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Target allocation maximum percentage of investments in equity securities to total plan assets presented on a weighted-average basis as of the measurement date of the latest statement of financial position.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Target allocation minimum percentage of investments in equity securities to total plan assets presented on a weighted-average basis as of the measurement date of the latest statement of financial position.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
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- Definition

The aggregate percentage of the fair value of investments (categorized by debt securities, equity securities, real estate and other plan assets) to the fair value of total plan assets held as of the measurement date.

+ References

+ Details

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Balance Type:	na
Period Type:	instant