Regulatory Matters - Regulatory Assets (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	$ 4,607	$ 3,974
Regulatory assets – current	281	305
Total Regulatory Assets	4,888	4,279
Environmental remediation costs
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	1,105	991
System peak reduction and energy efficiency programs
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	1,057	783
COVID-19 pandemic deferrals
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	789	396
Revenue taxes
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	476	436
Deferred storm costs
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	206	270
Property tax reconciliation
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	169	121
Deferred derivative losses - long term
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	163	31
Electric vehicle make ready
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	73	33
MTA power reliability deferral
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	61	92
Pension and other postretirement benefits deferrals
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	48	279
Gas service line deferred costs
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	43	99
Legacy meters
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	17	20
Unrecognized pension and other postretirement costs
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	0	78
Other
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	400	345
Deferred derivative losses - short term
Regulatory Assets [Line Items]
Regulatory assets – current	269	184
Recoverable energy costs
Regulatory Assets [Line Items]
Regulatory assets – current	12	121
CECONY
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	4,314	3,669
Regulatory assets – current	254	286
CECONY | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	4,314	3,669
Regulatory assets – current	254	286
Total Regulatory Assets	4,568	3,955
CECONY | Environmental remediation costs | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	1,022	906
CECONY | System peak reduction and energy efficiency programs | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	1,038	780
CECONY | COVID-19 pandemic deferrals | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	782	389
CECONY | Revenue taxes | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	455	417
CECONY | Deferred storm costs | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	115	173
CECONY | Property tax reconciliation | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	169	121
CECONY | Deferred derivative losses - long term | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	148	26
CECONY | Electric vehicle make ready | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	68	30
CECONY | MTA power reliability deferral | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	61	92
CECONY | Pension and other postretirement benefits deferrals | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	39	240
CECONY | Gas service line deferred costs | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	43	99
CECONY | Legacy meters | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	0	0
CECONY | Unrecognized pension and other postretirement costs | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	0	78
CECONY | Other | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	374	318
CECONY | Deferred derivative losses - short term | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – current	253	178
CECONY | Recoverable energy costs | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – current	$ 1	$ 108