Regulatory Matters - Schedule of Regulatory Assets Not Earning a Return (Details) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Regulatory Assets [Line Items]
Regulatory assets not earning return	$ 1,766	$ 1,883
Subsidiaries | CECONY
Regulatory Assets [Line Items]
Regulatory assets not earning return	1,643	1,753
Unrecognized pension and other postretirement costs
Regulatory Assets [Line Items]
Regulatory assets not earning return	24	128
Unrecognized pension and other postretirement costs | Subsidiaries | CECONY
Regulatory Assets [Line Items]
Regulatory assets not earning return	10	110
Environmental remediation costs
Regulatory Assets [Line Items]
Regulatory assets not earning return	913	928
Environmental remediation costs | Subsidiaries | CECONY
Regulatory Assets [Line Items]
Regulatory assets not earning return	833	850
Revenue taxes
Regulatory Assets [Line Items]
Regulatory assets not earning return	408	375
Revenue taxes | Subsidiaries | CECONY
Regulatory Assets [Line Items]
Regulatory assets not earning return	392	359
COVID-19 Deferral for Uncollectible Accounts Receivable
Regulatory Assets [Line Items]
Regulatory assets not earning return	236	236
COVID-19 Deferral for Uncollectible Accounts Receivable | CECONY
Regulatory Assets [Line Items]
Regulatory assets not earning return	232	231
Deferred derivative losses - short term
Regulatory Assets [Line Items]
Regulatory assets not earning return	91	141
Deferred derivative losses - short term | Subsidiaries | CECONY
Regulatory Assets [Line Items]
Regulatory assets not earning return	88	134
Deferred derivative losses - long term
Regulatory Assets [Line Items]
Regulatory assets not earning return	32	51
Deferred derivative losses - long term | Subsidiaries | CECONY
Regulatory Assets [Line Items]
Regulatory assets not earning return	27	45
Other
Regulatory Assets [Line Items]
Regulatory assets not earning return	62	24
Other | Subsidiaries | CECONY
Regulatory Assets [Line Items]
Regulatory assets not earning return	$ 61	$ 24