Tax-Exempt Debt, Total

No definition available.

Name:	ed_TaxExemptDebt
Namespace Prefix:	ed_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=34725769&loc=d3e28878-108400

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399

+ Details

Name:	us-gaap_DebtInstrumentFaceAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Definition

The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

+ References

No definition available.

+ Details

Name:	us-gaap_LongTermDebtFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

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Namespace Prefix:
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- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=ed_CeconyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_SeniorNotesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=ed_SeniorNotes4.21Due2041Member
Namespace Prefix:
Data Type:	na
Balance Type:
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- Details

Name:	dei_LegalEntityAxis=ed_ConEdisonDevelopmentMember
Namespace Prefix:
Data Type:	na
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Period Type:

Capitalization - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2016	Feb. 29, 2016	Dec. 31, 2015
Schedule of Capitalization [Line Items]
Long-term debt, fair value	$ 14,710,000,000		$ 13,856,000,000
Level 2
Schedule of Capitalization [Line Items]
Long-term debt, fair value	14,074,000,000
Level 3
Schedule of Capitalization [Line Items]
Long-term debt, fair value	636,000,000
CECONY
Schedule of Capitalization [Line Items]
Long-term debt, fair value	12,995,000,000		$ 12,427,000,000
CECONY \| Level 2
Schedule of Capitalization [Line Items]
Long-term debt, fair value	12,359,000,000
CECONY \| Level 3
Schedule of Capitalization [Line Items]
Long-term debt, fair value	636,000,000
Tax-exempt debt	$ 636,000,000
Senior Notes \| 4.21% Senior Notes due 2041 \| Con Edison Development
Schedule of Capitalization [Line Items]
Debt Instrument, face amount		$ 218,000,000
Debt instrument, interest rate (percent)		4.21%