Regulatory Matters - Regulatory Liabilities (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	$ 5,067	$ 5,328
Regulatory liabilities – current	125	145
Total Regulatory Liabilities	5,192	5,473
Regulatory assets	5,096	4,607
Regulatory assets	167	281
Pension and other postretirement benefits deferrals
Regulatory Liabilities [Line Items]
Regulatory assets	9	48
Gas service line deferred costs
Regulatory Liabilities [Line Items]
Regulatory assets	29	43
Environmental remediation costs
Regulatory Liabilities [Line Items]
Regulatory assets	1,100	1,105
Deferred derivative losses - long term
Regulatory Liabilities [Line Items]
Regulatory assets	115	163
Deferred derivative losses - short term
Regulatory Liabilities [Line Items]
Regulatory assets	147	269
Recoverable energy costs
Regulatory Liabilities [Line Items]
Regulatory assets	20	12
Allowance for cost of removal less salvage
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	1,468	1,456
Future income tax
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	1,397	1,535
Unrecognized pension and other postretirement costs
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	793	943
Pension and other postretirement benefit deferrals
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	324	284
Net unbilled revenue deferrals
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	268	278
Late payment charge deferral
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	208	167
System benefit charge carrying charge
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	103	92
Net proceeds from sale of property
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	36	48
Deferred derivative gains - long term
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	26	49
Settlement of prudence proceeding
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	11	11
Other
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	433	465
Deferred derivative gains - short term
Regulatory Liabilities [Line Items]
Regulatory liabilities – current	60	74
Refundable energy costs
Regulatory Liabilities [Line Items]
Regulatory liabilities – current	52	71
Revenue decoupling mechanism
Regulatory Liabilities [Line Items]
Regulatory liabilities – current	13	0
CECONY
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	4,591	4,818
Regulatory liabilities – current	76	107
Regulatory assets	4,777	4,314
Regulatory assets	145	254
CECONY | Subsidiaries
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	4,591	4,818
Regulatory liabilities – current	76	107
Total Regulatory Liabilities	4,667	4,925
Regulatory assets	4,777	4,314
Regulatory assets	145	254
CECONY | Subsidiaries | Pension and other postretirement benefits deferrals
Regulatory Liabilities [Line Items]
Regulatory assets	8	39
CECONY | Subsidiaries | Gas service line deferred costs
Regulatory Liabilities [Line Items]
Regulatory assets	29	43
CECONY | Subsidiaries | Environmental remediation costs
Regulatory Liabilities [Line Items]
Regulatory assets	1,017	1,022
CECONY | Subsidiaries | Deferred derivative losses - long term
Regulatory Liabilities [Line Items]
Regulatory assets	104	148
CECONY | Subsidiaries | Deferred derivative losses - short term
Regulatory Liabilities [Line Items]
Regulatory assets	137	253
CECONY | Subsidiaries | Recoverable energy costs
Regulatory Liabilities [Line Items]
Regulatory assets	8	1
CECONY | Allowance for cost of removal less salvage | Subsidiaries
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	1,271	1,266
CECONY | Future income tax | Subsidiaries
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	1,279	1,404
CECONY | Unrecognized pension and other postretirement costs | Subsidiaries
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	746	867
CECONY | Pension and other postretirement benefit deferrals | Subsidiaries
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	270	233
CECONY | Net unbilled revenue deferrals | Subsidiaries
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	268	278
CECONY | Late payment charge deferral | Subsidiaries
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	202	161
CECONY | System benefit charge carrying charge | Subsidiaries
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	99	88
CECONY | Net proceeds from sale of property | Subsidiaries
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	35	47
CECONY | Deferred derivative gains - long term | Subsidiaries
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	24	49
CECONY | Settlement of prudence proceeding | Subsidiaries
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	11	11
CECONY | Other | Subsidiaries
Regulatory Liabilities [Line Items]
Regulatory liabilities – noncurrent	386	414
CECONY | Deferred derivative gains - short term | Subsidiaries
Regulatory Liabilities [Line Items]
Regulatory liabilities – current	55	71
CECONY | Refundable energy costs | Subsidiaries
Regulatory Liabilities [Line Items]
Regulatory liabilities – current	21	36
CECONY | Revenue decoupling mechanism | Subsidiaries
Regulatory Liabilities [Line Items]
Regulatory liabilities – current	$ 0	$ 0