v3.26.1
Regulatory Matters - Schedule of Regulatory Assets Not Earning a Return (Details) - USD ($)
$ in Millions
Jun. 30, 2026
Dec. 31, 2025
Regulatory Assets [Line Items]    
Regulatory assets not earning return $ 2,290 $ 2,281
Subsidiaries | CECONY    
Regulatory Assets [Line Items]    
Regulatory assets not earning return 2,140 2,137
Environmental investigation and remediation costs    
Regulatory Assets [Line Items]    
Regulatory assets not earning return 1,071 1,072
Environmental investigation and remediation costs | Subsidiaries | CECONY    
Regulatory Assets [Line Items]    
Regulatory assets not earning return 980 980
Revenue taxes    
Regulatory Assets [Line Items]    
Regulatory assets not earning return 651 621
Revenue taxes | Subsidiaries | CECONY    
Regulatory Assets [Line Items]    
Regulatory assets not earning return 623 595
UB deferral for uncollectible accounts receivable    
Regulatory Assets [Line Items]    
Regulatory assets not earning return 381 427
UB deferral for uncollectible accounts receivable | Subsidiaries | CECONY    
Regulatory Assets [Line Items]    
Regulatory assets not earning return 378 426
Deferred derivative losses - short term    
Regulatory Assets [Line Items]    
Regulatory assets not earning return 87 97
Deferred derivative losses - short term | Subsidiaries | CECONY    
Regulatory Assets [Line Items]    
Regulatory assets not earning return 80 90
Deferred derivative losses - long term    
Regulatory Assets [Line Items]    
Regulatory assets not earning return 24 18
Deferred derivative losses - long term | Subsidiaries | CECONY    
Regulatory Assets [Line Items]    
Regulatory assets not earning return 23 15
Unrecognized pension and other postretirement costs    
Regulatory Assets [Line Items]    
Regulatory assets not earning return 7 4
Unrecognized pension and other postretirement costs | Subsidiaries | CECONY    
Regulatory Assets [Line Items]    
Regulatory assets not earning return 0 0
Other    
Regulatory Assets [Line Items]    
Regulatory assets not earning return 69 42
Other | Subsidiaries | CECONY    
Regulatory Assets [Line Items]    
Regulatory assets not earning return $ 56 $ 31