Regulatory Matters - Schedule of Regulatory Assets Not Earning a Return (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Regulatory Assets [Line Items]
Regulatory assets not earning return	$ 2,311	$ 2,347
Subsidiaries | CECONY
Regulatory Assets [Line Items]
Regulatory assets not earning return	2,176	2,209
Environmental remediation costs
Regulatory Assets [Line Items]
Regulatory assets not earning return	1,098	1,105
Environmental remediation costs | Subsidiaries | CECONY
Regulatory Assets [Line Items]
Regulatory assets not earning return	1,015	1,022
Revenue taxes
Regulatory Assets [Line Items]
Regulatory assets not earning return	509	490
Revenue taxes | Subsidiaries | CECONY
Regulatory Assets [Line Items]
Regulatory assets not earning return	488	470
COVID-19 deferral for uncollectible accounts receivable
Regulatory Assets [Line Items]
Regulatory assets not earning return	324	291
COVID-19 deferral for uncollectible accounts receivable | Subsidiaries | CECONY
Regulatory Assets [Line Items]
Regulatory assets not earning return	318	288
Deferred derivative losses - short term
Regulatory Assets [Line Items]
Regulatory assets not earning return	202	269
Deferred derivative losses - short term | Subsidiaries | CECONY
Regulatory Assets [Line Items]
Regulatory assets not earning return	191	253
Deferred derivative losses - long term
Regulatory Assets [Line Items]
Regulatory assets not earning return	133	163
Deferred derivative losses - long term | Subsidiaries | CECONY
Regulatory Assets [Line Items]
Regulatory assets not earning return	121	148
Unrecognized pension and other postretirement costs
Regulatory Assets [Line Items]
Regulatory assets not earning return	4	0
Unrecognized pension and other postretirement costs | Subsidiaries | CECONY
Regulatory Assets [Line Items]
Regulatory assets not earning return	3	0
Other
Regulatory Assets [Line Items]
Regulatory assets not earning return	41	29
Other | Subsidiaries | CECONY
Regulatory Assets [Line Items]
Regulatory assets not earning return	$ 40	$ 28