Material Contingencies - Total Guarantees (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Guarantor Obligations [Line Items]
Total guarantees, by type and term	$ 175	$ 2,412
Con Edison Transmission
Guarantor Obligations [Line Items]
Total guarantees, by type and term	76
Guarantees on behalf of the Clean Energy Businesses
Guarantor Obligations [Line Items]
Total guarantees, by type and term	90
Broken Bow II
Guarantor Obligations [Line Items]
Total guarantees, by type and term	9
0 – 3 years
Guarantor Obligations [Line Items]
Total guarantees, by type and term	134
0 – 3 years | Con Edison Transmission
Guarantor Obligations [Line Items]
Total guarantees, by type and term	76
0 – 3 years | Guarantees on behalf of the Clean Energy Businesses
Guarantor Obligations [Line Items]
Total guarantees, by type and term	58
0 – 3 years | Broken Bow II
Guarantor Obligations [Line Items]
Total guarantees, by type and term	0
4 – 10 years
Guarantor Obligations [Line Items]
Total guarantees, by type and term	0
4 – 10 years | Guarantees on behalf of the Clean Energy Businesses
Guarantor Obligations [Line Items]
Total guarantees, by type and term	0
4 – 10 years | Broken Bow II
Guarantor Obligations [Line Items]
Total guarantees, by type and term	0
> 10 years
Guarantor Obligations [Line Items]
Total guarantees, by type and term	41
> 10 years | Con Edison Transmission
Guarantor Obligations [Line Items]
Total guarantees, by type and term	0
> 10 years | Guarantees on behalf of the Clean Energy Businesses
Guarantor Obligations [Line Items]
Total guarantees, by type and term	32
> 10 years | Broken Bow II
Guarantor Obligations [Line Items]
Total guarantees, by type and term	$ 9