Regulatory Matters - Regulatory Assets (Details) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	$ 3,659	$ 3,639
Regulatory assets – current	221	206
Total Regulatory Assets	3,880	3,845
Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	3,336	3,316
Regulatory assets – current	205	188
Environmental remediation costs
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	926	938
System peak reduction and energy efficiency programs
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	426	285
Pension and other postretirement benefits deferrals
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	417	496
Revenue taxes
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	414	395
COVID-19 pandemic deferrals
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	313	282
Deferred storm costs
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	279	276
Property tax reconciliation
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	154	202
MTA power reliability deferral
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	116	140
Gas Service Line Deferred Costs
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	108	100
Deferred derivative losses - long term
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	81	51
Municipal infrastructure support costs
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	37	44
Brooklyn Queens demand management program
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	34	36
Meadowlands heater odorization project
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	28	29
Unrecognized pension and other postretirement costs
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	27	128
Non-wire alternative projects
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	23	23
Preferred stock redemption
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	20	20
Legacy meters
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	20	2
Recoverable REV demonstration project costs
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	19	16
Unamortized loss on reacquired debt
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	13	16
Gate station upgrade project
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	13	14
Other
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	191	146
Deferred derivative losses - short term
Regulatory Assets [Line Items]
Regulatory assets – current	131	141
Recoverable energy costs
Regulatory Assets [Line Items]
Regulatory assets – current	90	65
CECONY | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	3,336	3,316
Regulatory assets – current	205	188
Total Regulatory Assets	3,541	3,504
CECONY | Environmental remediation costs | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	847	860
CECONY | System peak reduction and energy efficiency programs | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	431	284
CECONY | Pension and other postretirement benefits deferrals | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	368	435
CECONY | Revenue taxes | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	396	378
CECONY | COVID-19 pandemic deferrals | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	305	277
CECONY | Deferred storm costs | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	172	158
CECONY | Property tax reconciliation | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	154	202
CECONY | MTA power reliability deferral | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	116	140
CECONY | Gas Service Line Deferred Costs | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	108	100
CECONY | Deferred derivative losses - long term | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	73	45
CECONY | Municipal infrastructure support costs | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	37	44
CECONY | Brooklyn Queens demand management program | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	34	36
CECONY | Meadowlands heater odorization project | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	28	29
CECONY | Unrecognized pension and other postretirement costs | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	8	110
CECONY | Non-wire alternative projects | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	23	23
CECONY | Preferred stock redemption | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	20	20
CECONY | Legacy meters | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	0	0
CECONY | Recoverable REV demonstration project costs | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	18	15
CECONY | Unamortized loss on reacquired debt | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	12	14
CECONY | Gate station upgrade project | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	13	14
CECONY | Other | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – noncurrent	173	132
CECONY | Deferred derivative losses - short term | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – current	125	133
CECONY | Recoverable energy costs | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets – current	$ 80	$ 55