Material Contingencies - Total Guarantees (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Guarantor Obligations [Line Items]
Total guarantees, by type and term	$ 58	$ 175
Con Edison Transmission
Guarantor Obligations [Line Items]
Total guarantees, by type and term	49
Broken Bow II (a)
Guarantor Obligations [Line Items]
Total guarantees, by type and term	9
0 – 3 years
Guarantor Obligations [Line Items]
Total guarantees, by type and term	49
0 – 3 years | Con Edison Transmission
Guarantor Obligations [Line Items]
Total guarantees, by type and term	49
0 – 3 years | Broken Bow II (a)
Guarantor Obligations [Line Items]
Total guarantees, by type and term	0
> 10 years
Guarantor Obligations [Line Items]
Total guarantees, by type and term	9
> 10 years | Con Edison Transmission
Guarantor Obligations [Line Items]
Total guarantees, by type and term	0
> 10 years | Broken Bow II (a)
Guarantor Obligations [Line Items]
Total guarantees, by type and term	$ 9