XML 82 R57.htm IDEA: XBRL DOCUMENT
v3.20.4

Summary of Significant Accounting Policies and Other Matters - Revenues (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Revenue from External Customer [Line Items] |  |  |
Excise taxes | $ 335 | $ 323 | $ 330
CECONY |  |  |
Revenue from External Customer [Line Items] |  |  |
Excise taxes | $ 323 | $ 312 | $ 318

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

X
- Definition The excise taxes collected by a public utility and reported in revenues if the amount of excise taxes is equal to 1 percent or more of such total. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03(1)(e)) -URI http://asc.fasb.org/extlink&oid=120395209&loc=SL114868664-224227 + Details
Name: | us-gaap_ExciseTaxesCollected
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

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