Summary of Significant Accounting Policies and Other Matters - Schedule of Investments (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2021	May 31, 2021	Dec. 31, 2019
Schedule of Equity Method Investments [Line Items]
Supplemental retirement income plan assets	$ 583	$ 524
Deferred income plan assets	116	99
Other	3	3
Total investments	1,126	999
New York Transco, LLC
Schedule of Equity Method Investments [Line Items]
Undistributed Earnings, Basic	16	13
CECONY
Schedule of Equity Method Investments [Line Items]
Supplemental retirement income plan assets	560	502
Deferred income plan assets	116	99
Other	8	7
Total investments	684	608
New York Transco, LLC | Con Edison Transmission
Schedule of Equity Method Investments [Line Items]
Equity method investment	254	221
New York Transco, LLC | Con Edison Transmission | CECONY
Schedule of Equity Method Investments [Line Items]
Equity method investment	0	0
Mountain Valley Pipeline
Schedule of Equity Method Investments [Line Items]
Equity method investment	530	530
Undistributed Earnings, Basic	127	114
Mountain Valley Pipeline | CET Gas
Schedule of Equity Method Investments [Line Items]
Equity method investment			$ 166		$ 530
Aggregate project cost	8,100			$ 8,100
Mountain Valley Pipeline | Con Edison Transmission
Schedule of Equity Method Investments [Line Items]
Equity method investment	166	144
Mountain Valley Pipeline | Con Edison Transmission | CECONY
Schedule of Equity Method Investments [Line Items]
Equity method investment	0	0
Virginia Tax Equity Project
Schedule of Equity Method Investments [Line Items]
Equity method investment	4	8
Virginia Tax Equity Project | CECONY
Schedule of Equity Method Investments [Line Items]
Equity method investment	$ 0	$ 0