Regulatory Matters - Regulatory Assets (Details) - USD ($) $ in Millions	Mar. 31, 2024	Jan. 01, 2024	Dec. 31, 2023	Jan. 01, 2022
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	$ 5,050		$ 4,607
Regulatory assets – current	210		281
Total Regulatory Assets	5,260		4,888
Environmental remediation costs
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	1,098		1,105
System peak reduction and energy efficiency programs
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	1,046		1,057
COVID - 19 pandemic deferrals
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	827		789
Revenue taxes
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	494		476
Legacy meters
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	436		17
Deferred storm costs
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	190		206
Property tax reconciliation
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	146		169
Deferred derivative losses - long term
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	133		163
Electric vehicle make ready
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	85		73
Pension and other postretirement benefits deferrals
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	73		48
MTA power reliability deferral
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	54		61
Gas service line deferred costs
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	38		43
Unrecognized pension and other postretirement costs
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	4		0
Other
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	426		400
Deferred derivative losses - short term
Regulatory Assets [Line Items]
Regulatory assets – current	202		269
Recoverable energy costs
Regulatory Assets [Line Items]
Regulatory assets – current	8		12
CECONY
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	4,757		4,314
Regulatory assets – current	191		254
CECONY | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	4,757		4,314
Regulatory assets – current	191		254
Total Regulatory Assets	4,948		4,568
CECONY | Environmental remediation costs | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	1,015		1,022
CECONY | System peak reduction and energy efficiency programs | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	1,024		1,038
CECONY | COVID - 19 pandemic deferrals | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	816		782
CECONY | Revenue taxes | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	473		455
CECONY | Legacy meters | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	420		0
CECONY | Deferred storm costs | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	100		115
CECONY | Property tax reconciliation | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	146		169
CECONY | Deferred derivative losses - long term | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	121		148
CECONY | Electric vehicle make ready | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	79		68
CECONY | Pension and other postretirement benefits deferrals | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	70		39
CECONY | MTA power reliability deferral | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	54		61
CECONY | Gas service line deferred costs | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	38		43
CECONY | Unrecognized pension and other postretirement costs | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	3		0
CECONY | Other | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	398		374
CECONY | Deferred derivative losses - short term | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – current	191		253
CECONY | Recoverable energy costs | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – current	$ 0		$ 1
Consolidated Edison Company of New York, Inc. And Orange And Rockland | Legacy meters
Regulatory Assets [Line Items]
Cost of the program, recovery period (in years)		15 years		12 years