Regulatory Matters - Regulatory Assets (Details) - USD ($) $ in Millions	Sep. 30, 2024	Jan. 01, 2024	Dec. 31, 2023	Jan. 01, 2022
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	$ 5,317		$ 4,607
Regulatory assets – current	224		281
Total Regulatory Assets	5,541		4,888
System peak reduction and energy efficiency programs
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	1,204		1,095
Environmental remediation costs
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	1,093		1,105
COVID - 19 pandemic deferrals
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	888		789
Revenue taxes
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	525		476
Legacy meters
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	420		17
Property tax reconciliation
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	176		169
Deferred storm costs
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	169		206
Deferred derivative losses - long term
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	154		163
Electric vehicle make ready
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	115		73
MTA power reliability deferral
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	38		61
Gas service line deferred costs
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	23		43
Unrecognized pension and other postretirement costs
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	10		0
Pension and other postretirement benefits deferrals
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	5		48
Other
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	497		362
Deferred derivative losses - short term
Regulatory Assets [Line Items]
Regulatory assets – current	165		269
Recoverable energy costs
Regulatory Assets [Line Items]
Regulatory assets – current	59		12
CECONY
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	4,971		4,314
Regulatory assets – current	193		254
CECONY | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	4,971		4,314
Regulatory assets – current	193		254
Total Regulatory Assets	5,164		4,568
CECONY | System peak reduction and energy efficiency programs | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	1,172		1,075
CECONY | Environmental remediation costs | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	1,010		1,022
CECONY | COVID - 19 pandemic deferrals | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	875		782
CECONY | Revenue taxes | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	503		455
CECONY | Legacy meters | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	405		0
CECONY | Property tax reconciliation | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	176		169
CECONY | Deferred storm costs | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	67		115
CECONY | Deferred derivative losses - long term | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	138		148
CECONY | Electric vehicle make ready | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	105		68
CECONY | MTA power reliability deferral | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	38		61
CECONY | Gas service line deferred costs | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	23		43
CECONY | Unrecognized pension and other postretirement costs | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	10		0
CECONY | Pension and other postretirement benefits deferrals | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	5		39
CECONY | Other | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	444		337
CECONY | Deferred derivative losses - short term | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – current	151		253
CECONY | Recoverable energy costs | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – current	$ 42		$ 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