Regulatory Matters - Other Regulatory Matters Narrative (Details) - USD ($) $ in Millions		9 Months Ended	12 Months Ended
	Nov. 06, 2025	Sep. 30, 2025	Dec. 31, 2024	May 31, 2024	Dec. 31, 2023
Public Utilities, General Disclosures [Line Items]
Other customer-provided capital rate (in percent)		4.75%	5.95%
Return on regulatory assets		$ 3,220.0	$ 3,262.0
Deferred derivative losses recovery period, current (in years)		1 year
Recovery period for deferred derivative losses (in years)		3 years
CECONY
Public Utilities, General Disclosures [Line Items]
Billing system costs		$ 510.0
Estimated capitalization costs		89.0
Incremental costs				$ 51.0
Net regulatory assets		1,042.0	1,078.0
Return on regulatory assets		$ 3,008.0	3,024.0
CECONY | Subsequent Event
Public Utilities, General Disclosures [Line Items]
Annual gas revenue requirement amount	$ 33.3
Rate adjustment mechanism	$ 100.0
CECONY | Commodity
Public Utilities, General Disclosures [Line Items]
Recovery period (in years)		4 years
O&R
Public Utilities, General Disclosures [Line Items]
Net regulatory assets		$ 10.0	14.0
RECO | Subsidiaries
Public Utilities, General Disclosures [Line Items]
Return on regulatory assets		33.0	$ 28.0
Maximum | CECONY
Public Utilities, General Disclosures [Line Items]
Capital expenditures limit		$ 421.0		$ 421.0	$ 38.0