Material Contingencies - Guarantees (Details) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Guarantor Obligations [Line Items]
Total guarantees, by type and term	$ 568	$ 2,412
Con Edison Transmission
Guarantor Obligations [Line Items]
Total guarantees, by type and term	365
Guarantees on behalf of the Clean Energy Businesses
Guarantor Obligations [Line Items]
Total guarantees, by type and term	194
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	528
0 – 3 years | Con Edison Transmission
Guarantor Obligations [Line Items]
Total guarantees, by type and term	365
0 – 3 years | Guarantees on behalf of the Clean Energy Businesses
Guarantor Obligations [Line Items]
Total guarantees, by type and term	163
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
Greater than 10 years
Guarantor Obligations [Line Items]
Total guarantees, by type and term	40
Greater than 10 years | Con Edison Transmission
Guarantor Obligations [Line Items]
Total guarantees, by type and term	0
Greater than 10 years | Guarantees on behalf of the Clean Energy Businesses
Guarantor Obligations [Line Items]
Total guarantees, by type and term	31
Greater than 10 years | Broken Bow II
Guarantor Obligations [Line Items]
Total guarantees, by type and term	$ 9