Related Party Transactions - Summary of Costs of Administrative and Other Services Provided and Received (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Related Party Transaction [Line Items]
Cost of services provided	$ 3,595	$ 3,220	$ 8,393	$ 7,495
Cost of services received	3,240	2,900	6,913	6,134
CECONY
Related Party Transaction [Line Items]
Cost of services provided	3,340	2,996	7,782	6,967
Cost of services received	2,993	2,682	6,368	5,663
CECONY | Related Party
Related Party Transaction [Line Items]
Cost of services provided	37	35	77	68
Cost of services received	$ 22	$ 21	$ 42	$ 41