v3.26.1
Derivative Instruments and Hedging Activities - Schedule of Realized and Unrealized Gains (Losses) on Commodity Derivatives (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Pre-tax gains (losses) deferred in accordance with accounting rules for regulated operations:        
Total deferred gains (losses) $ 140 $ (80) $ 153 $ 19
Total deferred gains (losses) (56) 66 191 50
Net deferred gains (losses) 84 (14) 344 69
Other operations and maintenance 0   3  
Balance Sheet Location [Axis]: us-gaap:RegulatoryAssetsCurrent        
Pre-tax gains (losses) deferred in accordance with accounting rules for regulated operations:        
Total deferred gains (losses) (12) 100 10 (5)
Balance Sheet Location [Axis]: us-gaap:RegulatoryAssetsCurrent | Recoverable energy costs        
Pre-tax gains (losses) deferred in accordance with accounting rules for regulated operations:        
Total deferred gains (losses) (43) (77) 188 54
Balance Sheet Location [Axis]: us-gaap:RegulatoryAssetsNoncurrent        
Pre-tax gains (losses) deferred in accordance with accounting rules for regulated operations:        
Total deferred gains (losses) (1) 43 (7) 1
Balance Sheet Location [Axis]: us-gaap:RegulatoryLiabilityCurrent        
Pre-tax gains (losses) deferred in accordance with accounting rules for regulated operations:        
Total deferred gains (losses) 67 (85) 131 2
Balance Sheet Location [Axis]: us-gaap:RegulatoryLiabilityNoncurrent        
Pre-tax gains (losses) deferred in accordance with accounting rules for regulated operations:        
Total deferred gains (losses) 73 5 22 17
CECONY | Subsidiaries        
Pre-tax gains (losses) deferred in accordance with accounting rules for regulated operations:        
Total deferred gains (losses) 136 (73) 146 19
Total deferred gains (losses) (51) 62 174 46
Net deferred gains (losses) 85 (11) 320 65
Other operations and maintenance 0   3  
CECONY | Balance Sheet Location [Axis]: us-gaap:RegulatoryAssetsCurrent | Subsidiaries        
Pre-tax gains (losses) deferred in accordance with accounting rules for regulated operations:        
Total deferred gains (losses) (9) 93 11 (5)
CECONY | Balance Sheet Location [Axis]: us-gaap:RegulatoryAssetsCurrent | Subsidiaries | Recoverable energy costs        
Pre-tax gains (losses) deferred in accordance with accounting rules for regulated operations:        
Total deferred gains (losses) (41) (71) 171 51
CECONY | Balance Sheet Location [Axis]: us-gaap:RegulatoryAssetsNoncurrent | Subsidiaries        
Pre-tax gains (losses) deferred in accordance with accounting rules for regulated operations:        
Total deferred gains (losses) (1) 40 (8) 0
CECONY | Balance Sheet Location [Axis]: us-gaap:RegulatoryLiabilityCurrent | Subsidiaries        
Pre-tax gains (losses) deferred in accordance with accounting rules for regulated operations:        
Total deferred gains (losses) 65 (77) 123 2
CECONY | Balance Sheet Location [Axis]: us-gaap:RegulatoryLiabilityNoncurrent | Subsidiaries        
Pre-tax gains (losses) deferred in accordance with accounting rules for regulated operations:        
Total deferred gains (losses) $ 71 $ 4 $ 23 $ 17