Income Tax - Additional Information (Details) - USD ($)	3 Months Ended			9 Months Ended
	Sep. 30, 2022	Jun. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Income Taxes Disclosure [Line Items]
Income tax expense (benefit)	$ 160,000,000		$ 127,000,000	$ 330,000,000	$ 194,000,000
Increase in reserve due to settlement		$ 5,000,000
Estimated liability for uncertain tax positions	21,000,000			21,000,000
Effective income tax rate reconciliation, uncertainty of taxes				17,000,000
Total amount of unrecognized tax benefits, if recognized, that would reduce effective tax rate	21,000,000			21,000,000
Penalties recognized for uncertain tax positions				0	0
Subsidiaries
Income Taxes Disclosure [Line Items]
Income tax expense (benefit)	124,000,000		90,000,000	232,000,000	$ 188,000,000
CECONY | Subsidiaries
Income Taxes Disclosure [Line Items]
Income tax expense (benefit)	124,000,000		$ 90,000,000
Estimated liability for uncertain tax positions	7,000,000			7,000,000
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	$ 7,000,000			$ 7,000,000