Regulatory Matters - Schedule of Regulatory Assets Not Earning a Return (Details) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Regulatory Assets [Line Items]
Regulatory assets not earning return	$ 1,872	$ 1,883
Subsidiaries | CECONY
Regulatory Assets [Line Items]
Regulatory assets not earning return	1,735	1,753
Unrecognized pension and other postretirement costs
Regulatory Assets [Line Items]
Regulatory assets not earning return	27	128
Unrecognized pension and other postretirement costs | Subsidiaries | CECONY
Regulatory Assets [Line Items]
Regulatory assets not earning return	8	110
Environmental remediation costs
Regulatory Assets [Line Items]
Regulatory assets not earning return	916	928
Environmental remediation costs | Subsidiaries | CECONY
Regulatory Assets [Line Items]
Regulatory assets not earning return	837	850
Revenue taxes
Regulatory Assets [Line Items]
Regulatory assets not earning return	393	375
Revenue taxes | Subsidiaries | CECONY
Regulatory Assets [Line Items]
Regulatory assets not earning return	377	359
COVID-19 Deferral for Uncollectible Accounts Receivable
Regulatory Assets [Line Items]
Regulatory assets not earning return	274	236
COVID-19 Deferral for Uncollectible Accounts Receivable | CECONY
Regulatory Assets [Line Items]
Regulatory assets not earning return	266	231
Deferred derivative losses - short term
Regulatory Assets [Line Items]
Regulatory assets not earning return	131	141
Deferred derivative losses - short term | Subsidiaries | CECONY
Regulatory Assets [Line Items]
Regulatory assets not earning return	125	134
Deferred derivative losses - long term
Regulatory Assets [Line Items]
Regulatory assets not earning return	81	51
Deferred derivative losses - long term | Subsidiaries | CECONY
Regulatory Assets [Line Items]
Regulatory assets not earning return	73	45
Other
Regulatory Assets [Line Items]
Regulatory assets not earning return	50	24
Other | Subsidiaries | CECONY
Regulatory Assets [Line Items]
Regulatory assets not earning return	$ 49	$ 24