Regulatory Matters - Schedule of Regulatory Assets Not Earning a Return (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Regulatory Assets [Line Items]
Regulatory assets not earning return	$ 2,347	$ 1,975
CECONY
Regulatory Assets [Line Items]
Regulatory assets not earning return	2,209	1,858
Unrecognized pension and other postretirement costs
Regulatory Assets [Line Items]
Regulatory assets not earning return	0	78
Unrecognized pension and other postretirement costs | CECONY
Regulatory Assets [Line Items]
Regulatory assets not earning return	0	78
Environmental remediation costs
Regulatory Assets [Line Items]
Regulatory assets not earning return	1,105	987
Environmental remediation costs | CECONY
Regulatory Assets [Line Items]
Regulatory assets not earning return	1,022	903
Revenue taxes
Regulatory Assets [Line Items]
Regulatory assets not earning return	490	414
Revenue taxes | CECONY
Regulatory Assets [Line Items]
Regulatory assets not earning return	470	397
Deferred derivative losses - long term
Regulatory Assets [Line Items]
Regulatory assets not earning return	163	31
Deferred derivative losses - long term | CECONY
Regulatory Assets [Line Items]
Regulatory assets not earning return	148	26
COVID-19 deferral for uncollectible accounts receivable
Regulatory Assets [Line Items]
Regulatory assets not earning return	291	253
COVID-19 deferral for uncollectible accounts receivable | CECONY
Regulatory Assets [Line Items]
Regulatory assets not earning return	288	249
Other
Regulatory Assets [Line Items]
Regulatory assets not earning return	29	28
Other | CECONY
Regulatory Assets [Line Items]
Regulatory assets not earning return	28	27
Deferred derivative losses - short term
Regulatory Assets [Line Items]
Regulatory assets not earning return	269	184
Deferred derivative losses - short term | CECONY
Regulatory Assets [Line Items]
Regulatory assets not earning return	$ 253	$ 178