Regulatory Matters - Schedule of Regulatory Assets Not Earning a Return (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Regulatory Assets [Line Items]
Regulatory assets not earning return	$ 2,281	$ 2,402
CECONY | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets not earning return	2,137	2,240
Environmental remediation costs
Regulatory Assets [Line Items]
Regulatory assets not earning return	1,072	1,037
Environmental remediation costs | CECONY | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets not earning return	980	942
Revenue taxes
Regulatory Assets [Line Items]
Regulatory assets not earning return	621	567
Revenue taxes | CECONY | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets not earning return	595	543
UB deferral for uncollectible accounts receivable
Regulatory Assets [Line Items]
Regulatory assets not earning return	427	551
UB deferral for uncollectible accounts receivable | CECONY | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets not earning return	426	541
Deferred derivative losses - short term
Regulatory Assets [Line Items]
Regulatory assets not earning return	97	102
Deferred derivative losses - short term | CECONY | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets not earning return	90	92
Deferred derivative losses - long term
Regulatory Assets [Line Items]
Regulatory assets not earning return	18	106
Deferred derivative losses - long term | CECONY | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets not earning return	15	94
Unrecognized pension and other postretirement costs
Regulatory Assets [Line Items]
Regulatory assets not earning return	4	0
Unrecognized pension and other postretirement costs | CECONY | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets not earning return	0	0
Other
Regulatory Assets [Line Items]
Regulatory assets not earning return	42	39
Other | CECONY | Subsidiaries
Regulatory Assets [Line Items]
Regulatory assets not earning return	$ 31	$ 28