Regulatory Matters - Summary of Utilities Rate Plans (O&R New York-Gas) (Details) - USD ($)	12 Months Ended			36 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2024	Dec. 31, 2021
Public Utilities, General Disclosures [Line Items]
Deferred revenues	$ 662,000,000	$ 599,000,000			$ 662,000,000
Earnings above threshold	$ 1,700,000
NYSPSC
Public Utilities, General Disclosures [Line Items]
Percentage of total consolidated revenues	15.00%				15.00%
Percentage of debt to total consolidated debt	20.00%				20.00%
Maximum | NYSPSC
Public Utilities, General Disclosures [Line Items]
Percentage of total consolidated revenues	15.00%				15.00%
O&R | Gas
Public Utilities, General Disclosures [Line Items]
Amount of revenues retained	$ 4,000,000				$ 4,000,000
Share in variances in annual revenue retained (percent)					20.00%
Potential earnings adjustment mechanism incentives					$ 300,000
Deferred revenues	4,000,000	500,000	$ 800,000		4,000,000
Negative revenue adjustments			200,000
Cost reconciliation, deferred net regulatory liabilities			6,000,000
Cost reconciliation, deferred net regulatory assets	$ 8,000,000	1,800,000			$ 8,000,000
Earnings sharing (percent)	9.60%				9.60%
Common equity ratio, percentage					48.00%
O&R | Gas | Customers
Public Utilities, General Disclosures [Line Items]
Share in variances in annual revenue retained (percent)					80.00%
O&R | Gas | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Earnings sharing (percent)				9.70%
Deferrals for property taxes limitation from rates (percent)				90.00%
O&R | Gas | Year 1
Public Utilities, General Disclosures [Line Items]
Base rate changes					$ (7,500,000)
Amortization to income of net regulatory assets					1,800,000
Potential earnings adjustment mechanism incentives					1,200,000
Net utility plant reconciliations					593,000,000
Average rate base					$ 454,000,000
Weighted average cost of capital (after-tax) (percent)					6.97%
Actual return on common equity (percent)					8.90%
Cost of long-term debt (percent)					5.17%
Requested rate increase (decrease), amount					$ (5,900,000)
O&R | Gas | Year 1 | AMI
Public Utilities, General Disclosures [Line Items]
Net utility plant reconciliations					20,000,000
O&R | Gas | Year 1 | Maximum
Public Utilities, General Disclosures [Line Items]
Potential penalties (annually)					5,500,000
O&R | Gas | Year 1 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Base rate changes				$ 700,000
Amortization to income of net regulatory assets				800,000
Potential earnings adjustment mechanism incentives				200,000
Potential positive rate adjustment for gas safety and performance				1,200,000
Net utility plant reconciliations				720,000,000
Average rate base				$ 566,000,000
Weighted average cost of capital (after-tax) (percent)				6.77%
Cost of long-term debt (percent)				4.58%
Requested rate increase (decrease), amount				$ 4,400,000
Deferral, annual maximum (not more than) (percent)				0.10%
O&R | Gas | Year 1 | Scenario, Forecast | Maximum
Public Utilities, General Disclosures [Line Items]
Potential penalties (annually)				$ 6,300,000
O&R | Gas | Year 2
Public Utilities, General Disclosures [Line Items]
Base rate changes					3,600,000
Amortization to income of net regulatory assets					1,800,000
Potential earnings adjustment mechanism incentives					1,300,000
Net utility plant reconciliations					611,000,000
Average rate base					$ 476,000,000
Weighted average cost of capital (after-tax) (percent)					6.96%
Actual return on common equity (percent)					9.58%
Cost of long-term debt (percent)					5.14%
Requested rate increase (decrease), amount					$ 1,000,000
O&R | Gas | Year 2 | AMI
Public Utilities, General Disclosures [Line Items]
Net utility plant reconciliations					24,000,000
O&R | Gas | Year 2 | Maximum
Public Utilities, General Disclosures [Line Items]
Potential penalties (annually)					5,700,000
O&R | Gas | Year 2 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Base rate changes				7,400,000
Amortization to income of net regulatory assets				700,000
Potential earnings adjustment mechanism incentives				200,000
Potential positive rate adjustment for gas safety and performance				1,300,000
Net utility plant reconciliations				761,000,000
Average rate base				$ 607,000,000
Weighted average cost of capital (after-tax) (percent)				6.73%
Cost of long-term debt (percent)				4.51%
Requested rate increase (decrease), amount				$ 4,400,000
Deferral, annual maximum (not more than) (percent)				0.075%
O&R | Gas | Year 2 | Scenario, Forecast | Maximum
Public Utilities, General Disclosures [Line Items]
Potential penalties (annually)				$ 6,700,000
O&R | Gas | Year 3
Public Utilities, General Disclosures [Line Items]
Base rate changes					700,000
Amortization to income of net regulatory assets					1,800,000
Potential earnings adjustment mechanism incentives					1,300,000
Net utility plant reconciliations					632,000,000
Average rate base					$ 498,000,000
Weighted average cost of capital (after-tax) (percent)					6.96%
Actual return on common equity (percent)					10.11%
Cost of long-term debt (percent)					5.14%
Requested rate increase (decrease), amount					$ 1,000,000
O&R | Gas | Year 3 | AMI
Public Utilities, General Disclosures [Line Items]
Net utility plant reconciliations					25,000,000
O&R | Gas | Year 3 | Maximum
Public Utilities, General Disclosures [Line Items]
Potential penalties (annually)					$ 6,000,000
O&R | Gas | Year 3 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Base rate changes				9,900,000
Amortization to income of net regulatory assets				300,000
Potential earnings adjustment mechanism incentives				400,000
Potential positive rate adjustment for gas safety and performance				1,400,000
Net utility plant reconciliations				803,000,000
Average rate base				$ 649,000,000
Weighted average cost of capital (after-tax) (percent)				6.72%
Cost of long-term debt (percent)				4.49%
Requested rate increase (decrease), amount				$ 4,400,000
Deferral, annual maximum (not more than) (percent)				0.05%
O&R | Gas | Year 3 | Scenario, Forecast | Maximum
Public Utilities, General Disclosures [Line Items]
Potential penalties (annually)				$ 7,300,000
O&R | Electric
Public Utilities, General Disclosures [Line Items]
Deferred revenues		6,000,000	100,000
Negative revenue adjustments	$ 0	0	0
Earnings sharing (percent)	9.60%				9.60%
Common equity ratio, percentage					48.00%
Deferrals for property taxes limitation from rates (percent)					90.00%
O&R | Electric | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Earnings sharing (percent)				9.70%
O&R | Electric | Year 1
Public Utilities, General Disclosures [Line Items]
Base rate changes					$ 13,400,000
Amortization to income of net regulatory assets					1,500,000
Potential earnings adjustment mechanism incentives					3,600,000
Average rate base					$ 878,000,000
Weighted average cost of capital (after-tax) (percent)					6.97%
Actual return on common equity (percent)					9.60%
Cost of long-term debt (percent)					5.17%
Requested rate increase (decrease), amount					$ 8,600,000
Deferral, annual maximum (not more than) (percent)					10.00%
O&R | Electric | Year 1 | AMI
Public Utilities, General Disclosures [Line Items]
Net utility plant reconciliations					$ 48,000,000
O&R | Electric | Year 1 | Maximum
Public Utilities, General Disclosures [Line Items]
Potential penalties (annually)					4,400,000
O&R | Electric | Year 1 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Base rate changes				$ 4,900,000
Amortization to income of net regulatory assets				11,800,000
Potential earnings adjustment mechanism incentives				3,300,000
Net utility plant reconciliations				1,175,000,000
Average rate base				$ 1,021,000,000
Weighted average cost of capital (after-tax) (percent)				6.77%
Cost of long-term debt (percent)				4.58%
Requested rate increase (decrease), amount				$ 11,700,000
O&R | Electric | Year 1 | Scenario, Forecast | Maximum
Public Utilities, General Disclosures [Line Items]
Potential penalties (annually)				4,300,000
O&R | Electric | Year 2
Public Utilities, General Disclosures [Line Items]
Base rate changes					8,000,000
Amortization to income of net regulatory assets					1,500,000
Potential earnings adjustment mechanism incentives					4,000,000
Average rate base					$ 906,000,000
Weighted average cost of capital (after-tax) (percent)					6.96%
Actual return on common equity (percent)					8.76%
Cost of long-term debt (percent)					5.14%
Requested rate increase (decrease), amount					$ 12,100,000
Deferral, annual maximum (not more than) (percent)					7.50%
O&R | Electric | Year 2 | AMI
Public Utilities, General Disclosures [Line Items]
Net utility plant reconciliations					$ 58,000,000
O&R | Electric | Year 2 | Maximum
Public Utilities, General Disclosures [Line Items]
Potential penalties (annually)					4,400,000
O&R | Electric | Year 2 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Base rate changes				16,200,000
Amortization to income of net regulatory assets				13,500,000
Potential earnings adjustment mechanism incentives				2,300,000
Net utility plant reconciliations				1,198,000,000
Average rate base				$ 1,044,000,000
Weighted average cost of capital (after-tax) (percent)				6.73%
Cost of long-term debt (percent)				4.51%
Requested rate increase (decrease), amount				$ 11,700,000
O&R | Electric | Year 2 | Scenario, Forecast | Maximum
Public Utilities, General Disclosures [Line Items]
Potential penalties (annually)				4,400,000
O&R | Electric | Year 3
Public Utilities, General Disclosures [Line Items]
Base rate changes					5,800,000
Amortization to income of net regulatory assets					1,500,000
Potential earnings adjustment mechanism incentives					4,200,000
Average rate base					$ 948,000,000
Weighted average cost of capital (after-tax) (percent)					6.96%
Actual return on common equity (percent)					9.16%
Cost of long-term debt (percent)					5.14%
Requested rate increase (decrease), amount					$ 12,200,000
Deferral, annual maximum (not more than) (percent)					5.00%
O&R | Electric | Year 3 | AMI
Public Utilities, General Disclosures [Line Items]
Net utility plant reconciliations					$ 61,000,000
O&R | Electric | Year 3 | Maximum
Public Utilities, General Disclosures [Line Items]
Potential penalties (annually)					$ 4,500,000
O&R | Electric | Year 3 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Base rate changes				23,100,000
Amortization to income of net regulatory assets				15,200,000
Potential earnings adjustment mechanism incentives				4,000,000.0
Net utility plant reconciliations				1,304,000,000
Average rate base				$ 1,144,000,000
Weighted average cost of capital (after-tax) (percent)				6.72%
Cost of long-term debt (percent)				4.49%
Requested rate increase (decrease), amount				$ 11,700,000
O&R | Electric | Year 3 | Scenario, Forecast | Maximum
Public Utilities, General Disclosures [Line Items]
Potential penalties (annually)				$ 5,100,000
Energy Efficiency | O&R | Gas
Public Utilities, General Disclosures [Line Items]
Actual earnings adjustment mechanism incentives	$ 500,000
Energy Efficiency | O&R | Electric
Public Utilities, General Disclosures [Line Items]
Actual earnings adjustment mechanism incentives	1,800,000	1,900,000	2,600,000
Service Termination | O&R | Gas
Public Utilities, General Disclosures [Line Items]
Actual earnings adjustment mechanism incentives	200,000	300,000	700,000
Incentives reversed	300,000
Service Termination | O&R | Electric
Public Utilities, General Disclosures [Line Items]
Actual earnings adjustment mechanism incentives	0	$ 500,000	$ 200,000
Incentives reversed	$ 500,000