Regulatory Matters - Regulatory Assets (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	$ 5,523	$ 4,607
Regulatory assets – current	141	281
Total Regulatory Assets	5,664	4,888
Environmental remediation costs
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	1,038	1,105
System peak reduction and energy efficiency programs
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	1,656	1,251
COVID-19 pandemic deferrals
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	1,073	789
Revenue taxes
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	540	476
Deferred storm costs
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	147	206
Property tax reconciliation
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	131	169
Deferred derivative losses - long term
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	106	163
MTA power reliability deferral
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	31	61
Pension and other postretirement benefits deferrals
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	2	48
Gas service line deferred costs
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	18	43
Legacy meters (c)
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	413	17
Other
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	368	279
Deferred derivative losses - short term
Regulatory Assets [Line Items]
Regulatory assets – current	102	269
Recoverable energy costs
Regulatory Assets [Line Items]
Regulatory assets – current	39	12
CECONY
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	5,158	4,314
Regulatory assets – current	106	254
CECONY | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	5,158	4,314
Regulatory assets – current	106	254
Total Regulatory Assets	5,264	4,568
CECONY | Environmental remediation costs | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	952	1,022
CECONY | System peak reduction and energy efficiency programs | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	1,598	1,223
CECONY | COVID-19 pandemic deferrals | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	1,058	782
CECONY | Revenue taxes | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	517	455
CECONY | Deferred storm costs | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	53	115
CECONY | Property tax reconciliation | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	131	169
CECONY | Deferred derivative losses - long term | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	94	148
CECONY | MTA power reliability deferral | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	31	61
CECONY | Pension and other postretirement benefits deferrals | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	2	39
CECONY | Gas service line deferred costs | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	18	43
CECONY | Legacy meters (c) | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	398	0
CECONY | Other | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	306	257
CECONY | Deferred derivative losses - short term | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – current	92	253
CECONY | Recoverable energy costs | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – current	$ 14	$ 1