Regulatory Matters - Schedule of Regulatory Assets Not Earning a Return (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Regulatory Assets [Line Items]
Regulatory assets not earning return	$ 2,134	$ 1,975
Subsidiaries | CECONY
Regulatory Assets [Line Items]
Regulatory assets not earning return	2,010	1,858
Unrecognized pension and other postretirement costs
Regulatory Assets [Line Items]
Regulatory assets not earning return	123	78
Unrecognized pension and other postretirement costs | Subsidiaries | CECONY
Regulatory Assets [Line Items]
Regulatory assets not earning return	121	78
Environmental remediation costs
Regulatory Assets [Line Items]
Regulatory assets not earning return	985	987
Environmental remediation costs | Subsidiaries | CECONY
Regulatory Assets [Line Items]
Regulatory assets not earning return	900	903
Revenue taxes
Regulatory Assets [Line Items]
Regulatory assets not earning return	448	414
Revenue taxes | Subsidiaries | CECONY
Regulatory Assets [Line Items]
Regulatory assets not earning return	431	397
COVID-19 Deferral for Uncollectible Accounts Receivable
Regulatory Assets [Line Items]
Regulatory assets not earning return	174	253
COVID-19 Deferral for Uncollectible Accounts Receivable | Subsidiaries | CECONY
Regulatory Assets [Line Items]
Regulatory assets not earning return	172	249
Deferred derivative losses - short term
Regulatory Assets [Line Items]
Regulatory assets not earning return	199	184
Deferred derivative losses - short term | Subsidiaries | CECONY
Regulatory Assets [Line Items]
Regulatory assets not earning return	190	178
Deferred derivative losses - long term
Regulatory Assets [Line Items]
Regulatory assets not earning return	165	31
Deferred derivative losses - long term | Subsidiaries | CECONY
Regulatory Assets [Line Items]
Regulatory assets not earning return	156	26
Other
Regulatory Assets [Line Items]
Regulatory assets not earning return	40	28
Other | Subsidiaries | CECONY
Regulatory Assets [Line Items]
Regulatory assets not earning return	$ 40	$ 27