Summary of Significant Accounting Policies and Other Matters - Schedule of Investments (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Jun. 30, 2024	Dec. 31, 2019
Schedule of Equity Method Investments [Line Items]
Supplemental retirement income plan assets	$ 620	$ 583
Deferred income plan assets	125	116
Other	1	3
INVESTMENTS	1,213	1,126
New York Transco, LLC
Schedule of Equity Method Investments [Line Items]
Undistributed earnings, basic	13	16
Income (loss) from equity method investments	29
Income (loss) from equity method Investments, after tax	21
CECONY
Schedule of Equity Method Investments [Line Items]
Supplemental retirement income plan assets	598	560
Deferred income plan assets	125	116
Other	2	8
INVESTMENTS	725	684
New York Transco, LLC | Con Edison Transmission
Schedule of Equity Method Investments [Line Items]
Equity method investment	294	254
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	121	127
Mountain Valley Pipeline | CET Gas
Schedule of Equity Method Investments [Line Items]
Equity method investment	168			$ 530
Aggregate project cost	8,100		$ 8,100
Income (loss) from equity method investments	30
Income (loss) from equity method Investments, after tax	21
Mountain Valley Pipeline | Con Edison Transmission
Schedule of Equity Method Investments [Line Items]
Equity method investment	168	166
Mountain Valley Pipeline | Con Edison Transmission | CECONY
Schedule of Equity Method Investments [Line Items]
Equity method investment	0	0
Virginia Tax Equity Interest
Schedule of Equity Method Investments [Line Items]
Equity method investment	5	4
Virginia Tax Equity Interest | CECONY
Schedule of Equity Method Investments [Line Items]
Equity method investment	$ 0	$ 0