Current Expected Credit Losses - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Accounts, Notes, Loans and Financing Receivable [Line Items]
Increase (decrease) in allowance for uncollectible accounts resulting from COVID-19 pandemic	$ (5)	$ 27	$ (10)	$ 101
Subsidiaries \| CECONY
Accounts, Notes, Loans and Financing Receivable [Line Items]
Increase (decrease) in allowance for uncollectible accounts resulting from COVID-19 pandemic		$ 29	$ (5)	$ 95

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.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 310
-SubTopic 20
-Name Accounting Standards Codification
-Section 40
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481628/310-20-40-7

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481990/310-10-45-2

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