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Pension Benefits - Schedule of Employer Contribution to Defined Savings Plan (Details) - Defined Contribution Savings Plan - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items] |  |  |
Employer contribution to the defined savings plan | $ 52 | $ 49 | $ 45
CECONY |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Employer contribution to the defined savings plan | $ 43 | $ 42 | $ 39

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- 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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Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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- Definition Amount of discretionary contributions made by an employer to a defined contribution plan. + References No definition available. + Details
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Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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- Details
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Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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- Details
Name: | dei_LegalEntityAxis=ed_ConsolidatedEdisonCompanyofNewYorkInc.Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |