Income Tax - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Income Taxes Disclosure [Line Items]
Income tax expense (benefit)	$ 133	$ 144	$ 307	$ 416
Increase (decrease) in income taxes payable	(457)
Increase (decrease) in accumulated deferred tax liabilities	457
Accrued income taxes	73		73
Estimated liability for uncertain tax positions	13		13
Unrecognized tax benefits, increase resulting from current period tax positions			2
Effective income tax rate reconciliation, uncertainty of taxes			3
Unrecognized tax benefits, net	12		12
CECONY
Income Taxes Disclosure [Line Items]
Income tax expense (benefit)	119	109	301	297
Increase (decrease) in income taxes payable	(418)
Increase (decrease) in accumulated deferred tax liabilities	418
Accrued income taxes	64		64
CECONY | Subsidiaries
Income Taxes Disclosure [Line Items]
Income tax expense (benefit)	119	$ 109	301	$ 297
Estimated liability for uncertain tax positions	9		$ 9
O&R
Income Taxes Disclosure [Line Items]
Increase (decrease) in income taxes payable	(39)
Increase (decrease) in accumulated deferred tax liabilities	$ 39