Material Contingencies - Schedule of Guarantees (Details) - USD ($) $ in Millions	Mar. 31, 2026	Dec. 31, 2025
Guarantor Obligations [Line Items]
Total guarantees, by type and term	$ 59	$ 60
Con Edison Transmission
Guarantor Obligations [Line Items]
Total guarantees, by type and term	59
0 – 3 years
Guarantor Obligations [Line Items]
Total guarantees, by type and term	59
0 – 3 years | Con Edison Transmission
Guarantor Obligations [Line Items]
Total guarantees, by type and term	$ 59