Regulatory Matters - Regulatory Assets (Details) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	$ 3,705	$ 3,639
Regulatory assets – current	282	206
Total Regulatory Assets	3,987	3,845
Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	3,396	3,316
Regulatory assets – current	271	188
Environmental remediation costs
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	919	938
System peak reduction and energy efficiency programs
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	546	285
Pension and other postretirement benefits deferrals
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	369	496
Revenue taxes
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	428	395
COVID-19 pandemic deferrals
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	275	282
Deferred storm costs
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	270	276
Property tax reconciliation
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	142	202
MTA power reliability deferral
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	104	140
Gas Service Line Deferred Costs
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	107	100
COVID-19 arrears relief program deferral
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	91	0
Municipal infrastructure support costs
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	33	44
Brooklyn Queens demand management program
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	33	36
Deferred derivative losses - long term
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	32	51
Meadowlands heater odorization project
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	27	29
Unrecognized pension and other postretirement costs
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	24	128
Non-wire alternative projects
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	23	23
Legacy meters
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	20	2
Preferred stock redemption
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	19	20
Recoverable REV demonstration project costs
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	17	16
Gate station upgrade project
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	14	14
Unamortized loss on reacquired debt
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	12	16
Other
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	200	146
Deferred derivative losses - short term
Regulatory Assets [Line Items]
Regulatory assets – current	91	141
Recoverable energy costs
Regulatory Assets [Line Items]
Regulatory assets – current	191	65
CECONY | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	3,396	3,316
Regulatory assets – current	271	188
Total Regulatory Assets	3,667	3,504
CECONY | Environmental remediation costs | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	840	860
CECONY | System peak reduction and energy efficiency programs | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	546	284
CECONY | Pension and other postretirement benefits deferrals | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	325	435
CECONY | Revenue taxes | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	409	378
CECONY | COVID-19 pandemic deferrals | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	272	277
CECONY | Deferred storm costs | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	168	158
CECONY | Property tax reconciliation | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	140	202
CECONY | MTA power reliability deferral | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	104	140
CECONY | Gas Service Line Deferred Costs | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	107	100
CECONY | COVID-19 arrears relief program deferral | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	88	0
CECONY | Municipal infrastructure support costs | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	33	44
CECONY | Brooklyn Queens demand management program | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	33	36
CECONY | Deferred derivative losses - long term | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	27	45
CECONY | Meadowlands heater odorization project | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	27	29
CECONY | Unrecognized pension and other postretirement costs | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	10	110
CECONY | Non-wire alternative projects | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	23	23
CECONY | Legacy meters | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	0	0
CECONY | Preferred stock redemption | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	19	20
CECONY | Recoverable REV demonstration project costs | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	17	15
CECONY | Gate station upgrade project | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	14	14
CECONY | Unamortized loss on reacquired debt | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	11	14
CECONY | Other | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	183	132
CECONY | Deferred derivative losses - short term | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – current	88	133
CECONY | Recoverable energy costs | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – current	$ 183	$ 55