Summary of Significant Accounting Policies and Other Matters - Changes in Accumulated Other Comprehensive Income/(Loss) by Component (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
AOCI Attributable to Parent, Net of Tax [Roll Forward]
BALANCE AS OF BEGINNING OF PERIOD	$ 20,336	$ 19,065	$ 18,213
BALANCE AS OF BEGINNING OF PERIOD	20,037
TOTAL OTHER COMPREHENSIVE INCOME (LOSS), NET OF TAXES	17	30	(6)
BALANCE AS OF END OF PERIOD	20,889	20,336	19,065
BALANCE AS OF END OF PERIOD	20,687	20,037
Accumulated OCI
AOCI Attributable to Parent, Net of Tax [Roll Forward]
BALANCE AS OF BEGINNING OF PERIOD	5	(25)	(19)
BALANCE AS OF END OF PERIOD	22	5	(25)
Pension Plan Liabilities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
OCI before reclassifications, net of tax	13	22	(11)
Amounts reclassified from accumulated OCI related to pension plan liabilities, net of tax	4	8	5
TOTAL OTHER COMPREHENSIVE INCOME (LOSS), NET OF TAXES	17	30	(6)
OCI before reclassifications, tax	(5)	(8)	4
Amounts reclassified from accumulated OCI related to pension plan liabilities, tax	(1)	(3)	(2)
Accumulated OCI
AOCI Attributable to Parent, Net of Tax [Roll Forward]
BALANCE AS OF BEGINNING OF PERIOD	5	(25)	(19)
TOTAL OTHER COMPREHENSIVE INCOME (LOSS), NET OF TAXES	17	30	(6)
BALANCE AS OF END OF PERIOD	22	5	(25)
Pension Plan Liabilities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Amounts reclassified from accumulated OCI related to pension plan liabilities, tax
CECONY
AOCI Attributable to Parent, Net of Tax [Roll Forward]
BALANCE AS OF BEGINNING OF PERIOD	16,312	14,849	14,147
TOTAL OTHER COMPREHENSIVE INCOME (LOSS), NET OF TAXES	4	7	(1)
BALANCE AS OF END OF PERIOD	16,878	16,312	14,849
CECONY | Pension Plan Liabilities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Amounts reclassified from accumulated OCI related to pension plan liabilities, tax		(1)
CECONY | Accumulated OCI
AOCI Attributable to Parent, Net of Tax [Roll Forward]
BALANCE AS OF BEGINNING OF PERIOD	0	(7)	(6)
TOTAL OTHER COMPREHENSIVE INCOME (LOSS), NET OF TAXES	4	7	(1)
BALANCE AS OF END OF PERIOD	4	0	(7)
CECONY | Pension Plan Liabilities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
OCI before reclassifications, net of tax	3	5	(3)
Amounts reclassified from accumulated OCI related to pension plan liabilities, net of tax	1	2	2
TOTAL OTHER COMPREHENSIVE INCOME (LOSS), NET OF TAXES	4	7	(1)
OCI before reclassifications, tax	$ (1)	$ (2)	$ 1