Regulatory Matters - Schedule of Regulatory Assets Not Earning a Return (Details) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Regulatory Assets [Line Items]
Regulatory assets not earning return	$ 2,039	$ 1,975
Subsidiaries | CECONY
Regulatory Assets [Line Items]
Regulatory assets not earning return	1,921	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	123	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	449	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	205	253
COVID-19 Deferral for Uncollectible Accounts Receivable | Subsidiaries | CECONY
Regulatory Assets [Line Items]
Regulatory assets not earning return	202	249
Deferred derivative losses - short term
Regulatory Assets [Line Items]
Regulatory assets not earning return	159	184
Deferred derivative losses - short term | Subsidiaries | CECONY
Regulatory Assets [Line Items]
Regulatory assets not earning return	153	178
Deferred derivative losses - long term
Regulatory Assets [Line Items]
Regulatory assets not earning return	65	31
Deferred derivative losses - long term | Subsidiaries | CECONY
Regulatory Assets [Line Items]
Regulatory assets not earning return	60	26
Other
Regulatory Assets [Line Items]
Regulatory assets not earning return	53	28
Other | Subsidiaries | CECONY
Regulatory Assets [Line Items]
Regulatory assets not earning return	$ 52	$ 27