Other Postretirement Benefits - Additional Information (Details) - Other Postretirement Benefits - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Defined Benefit Plan Disclosure [Line Items]
Increase (decrease) in liability for other postretirement benefits	$ (164,000,000)	$ (50,000,000)
Noncurrent liabilities	224,000,000	72,000,000
Increase (decrease) in regulatory liabilities	123,000,000
Other comprehensive income (loss), unrecognized net losses	2,000,000
Other comprehensive (income) loss, prior service cost	0
Expected contributions	7,000,000
CECONY
Defined Benefit Plan Disclosure [Line Items]
Increase (decrease) in liability for other postretirement benefits	(138,000,000)	(21,000,000)
Noncurrent liabilities	154,000,000	$ 27,000,000
Increase (decrease) in regulatory liabilities	119,000,000
Other comprehensive income (loss), unrecognized net losses	1,000,000
Other comprehensive (income) loss, prior service cost	$ 0