Income Tax - Additional Information (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Income Taxes Disclosure [Line Items]
Income tax expense (benefit)	$ 17,000,000	$ (11,000,000)	$ 171,000,000	$ 68,000,000
Increase in reserve due to settlement	5,000,000
Estimated liability for uncertain tax positions	22,000,000		22,000,000
Effective income tax rate reconciliation, uncertainty of taxes			18,000,000
Total amount of unrecognized tax benefits, if recognized, that would reduce effective tax rate	22,000,000		22,000,000
Penalties recognized for uncertain tax positions			0	0
Subsidiaries
Income Taxes Disclosure [Line Items]
Income tax expense (benefit)	(10,000,000)	(16,000,000)	108,000,000	$ 98,000,000
CECONY | Subsidiaries
Income Taxes Disclosure [Line Items]
Income tax expense (benefit)	(10,000,000)	$ (16,000,000)
Estimated liability for uncertain tax positions	6,000,000		6,000,000
Effective income tax rate reconciliation, uncertainty of taxes			4,000,000
Total amount of unrecognized tax benefits, if recognized, that would reduce effective tax rate	$ 6,000,000		$ 6,000,000