v3.26.1
Fair Value Measurements - Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($)
$ in Millions
Jun. 30, 2026
Dec. 31, 2025
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative assets: $ 1,109 $ 956
Cash Value of Life Insurance Policies 144 138
CECONY | Subsidiaries    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative assets: 1,060 913
Netting Adjustment    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative assets: (128) (104)
Netting Adjustment | CECONY | Subsidiaries    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative assets: (123) (100)
Level 1    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative assets: 639 625
Level 1 | CECONY | Subsidiaries    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative assets: 624 610
Level 2    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative assets: 588 430
Cash Value of Life Insurance Policies 144 138
Level 2 | CECONY | Subsidiaries    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative assets: 552 401
Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative assets: 10 5
Level 3 | CECONY | Subsidiaries    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative assets: 7 2
Commodity    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative assets: 342 212
Derivative liabilities: $ 23 $ 54
Derivative Asset, Statement of Financial Position [Extensible Enumeration] Assets Assets
Commodity | CECONY | Subsidiaries    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative assets: $ 315 $ 191
Derivative liabilities: $ 17 $ 47
Derivative Asset, Statement of Financial Position [Extensible Enumeration] Assets Assets
Commodity | Netting Adjustment    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative assets: $ (128) $ (104)
Derivative liabilities: (54) (32)
Commodity | Netting Adjustment | CECONY | Subsidiaries    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative assets: (123) (100)
Derivative liabilities: (53) (32)
Commodity | Level 1    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative assets: 16 19
Derivative liabilities: 13 6
Commodity | Level 1 | CECONY | Subsidiaries    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative assets: 16 19
Derivative liabilities: 12 6
Commodity | Level 2    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative assets: 444 292
Derivative liabilities: 58 70
Commodity | Level 2 | CECONY | Subsidiaries    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative assets: 415 270
Derivative liabilities: 55 68
Commodity | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative assets: 10 5
Derivative liabilities: 6 10
Commodity | Level 3 | CECONY | Subsidiaries    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative assets: 7 2
Derivative liabilities: 3 5
Mutual Funds    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative assets: $ 623 $ 606
Derivative Asset, Statement of Financial Position [Extensible Enumeration] Assets Assets
Mutual Funds | CECONY | Subsidiaries    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative assets: $ 608 $ 591
Derivative Asset, Statement of Financial Position [Extensible Enumeration] Assets Assets
Mutual Funds | Level 1    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative assets: $ 623 $ 606
Mutual Funds | Level 1 | CECONY | Subsidiaries    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative assets: 608 591
Cash Value of Life Insurance Policies | CECONY | Subsidiaries    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative assets: 137 131
Cash Value of Life Insurance Policies | Level 2 | CECONY | Subsidiaries    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative assets: $ 137 $ 131