Regulatory Matters - Regulatory Assets (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	$ 4,350	$ 3,974
Regulatory assets – current	251	305
Total Regulatory Assets	4,601	4,279
Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	4,047	3,669
Regulatory assets – current	231	286
Unrecognized pension and other postretirement costs
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	123	78
Environmental remediation costs
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	986	991
Revenue taxes
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	453	436
Deferred storm costs
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	262	270
Municipal infrastructure support costs
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	29	29
Brooklyn Queens demand management program
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	32	33
Meadowlands heater odorization project
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	26	27
Recoverable Demonstration project costs
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	17	17
Gate station upgrade project
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	14	14
System peak reduction and energy efficiency programs
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	802	783
Unamortized loss on reacquired debt
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	10	11
Deferred derivative losses - long term
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	165	31
Property tax reconciliation
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	132	121
Legacy meters
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	20	20
Gas service line deferred costs
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	66	99
COVID - 19 customer arrears relief programs
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	441	104
Pension and other postretirement benefits deferrals
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	196	279
Preferred stock redemption
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	19	19
MTA power reliability deferral
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	84	92
Non-wire alternative projects
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	21	22
COVID - 19 pandemic deferrals
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	211	292
Electric vehicle make ready
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	39	33
Other
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	202	173
Deferred derivative losses - short term
Regulatory Assets [Line Items]
Regulatory assets – current	199	184
Recoverable energy costs
Regulatory Assets [Line Items]
Regulatory assets – current	52	121
CECONY | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	4,047	3,669
Regulatory assets – current	231	286
Total Regulatory Assets	4,278	3,955
CECONY | Unrecognized pension and other postretirement costs | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	121	78
CECONY | Environmental remediation costs | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	902	906
CECONY | Revenue taxes | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	433	417
CECONY | Deferred storm costs | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	158	173
CECONY | Municipal infrastructure support costs | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	29	29
CECONY | Brooklyn Queens demand management program | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	32	33
CECONY | Meadowlands heater odorization project | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	26	27
CECONY | Recoverable Demonstration project costs | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	17	16
CECONY | Gate station upgrade project | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	14	14
CECONY | System peak reduction and energy efficiency programs | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	796	780
CECONY | Unamortized loss on reacquired debt | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	9	10
CECONY | Deferred derivative losses - long term | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	156	26
CECONY | Property tax reconciliation | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	132	121
CECONY | Legacy meters | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	0	0
CECONY | Gas service line deferred costs | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	66	99
CECONY | COVID - 19 customer arrears relief programs | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	436	101
CECONY | Pension and other postretirement benefits deferrals | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	166	240
CECONY | Preferred stock redemption | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	19	19
CECONY | MTA power reliability deferral | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	84	92
CECONY | Non-wire alternative projects | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	21	22
CECONY | COVID - 19 pandemic deferrals | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	208	288
CECONY | Electric vehicle make ready | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	36	30
CECONY | Other | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	186	148
CECONY | Deferred derivative losses - short term | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – current	190	178
CECONY | Recoverable energy costs | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – current	$ 41	$ 108