Income Tax - Additional Information (Details) - USD ($)	3 Months Ended	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating Loss Carryforwards [Line Items]
Increase in effective tax rate (in percent)		10.00%
Increase to net deferred income tax liabilities	$ 111,000,000
Increase in valuation allowance	10,000,000
Deferred income taxes	121,000,000	$ 435,000,000	$ 133,000,000	$ 85,000,000
Write-off of deferred tax assets of other state net operating losses		11,000,000
Deferred income tax benefit from net operating losses		$ 3,000,000
State income tax rate (in percent)		6.00%	4.00%	4.00%
Unrecognized tax benefits	23,000,000	$ 23,000,000	$ 17,000,000	$ 14,000,000	$ 13,000,000
Effective income tax rate reconciliation, uncertainty of taxes		20,000,000
Unrecognized tax benefits that would have an impact on effective tax rate	23,000,000	23,000,000
Penalties for uncertain tax positions		0	0	0
Excise taxes paid		2,000,000
Uncertain tax positions, released		1,000,000
General Business Tax Credit
Operating Loss Carryforwards [Line Items]
Tax credit carryovers	767,000,000	767,000,000
State | New York State
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	892,000,000	892,000,000
Deferred tax assets	84,000,000	84,000,000
Expected taxable income minimum		$ 5,000,000
State income tax rate (in percent)		7.25%
State | New York City
Operating Loss Carryforwards [Line Items]
Deferred tax assets	17,000,000	$ 17,000,000
Valuation allowance reversed	14,000,000	$ 14,000,000
State | Metropolitan Transportation Authority Subcharge
Operating Loss Carryforwards [Line Items]
State income tax rate (in percent)		9.40%
State | Other States
Operating Loss Carryforwards [Line Items]
Deferred tax assets	46,000,000	$ 46,000,000
Valuation allowance reversed	10,000,000	10,000,000
CECONY
Operating Loss Carryforwards [Line Items]
Deferred income taxes		$ 85,000,000	$ 124,000,000	$ 168,000,000
State income tax rate (in percent)		5.00%	5.00%	5.00%
Unrecognized tax benefits	8,000,000	$ 8,000,000	$ 5,000,000	$ 3,000,000	$ 2,000,000
Effective income tax rate reconciliation, uncertainty of taxes		6,000,000
Unrecognized tax benefits that would have an impact on effective tax rate	$ 8,000,000	$ 8,000,000