Regulatory Matters - Summary of Utilities Rate Plans (O&R New York-Gas) (Details) - USD ($) $ in Millions	36 Months Ended
	Dec. 31, 2024	Sep. 30, 2021
NYSPSC
Public Utilities, General Disclosures [Line Items]
Percentage of total consolidated revenues		15.00%
Percentage of debt to total consolidated debt		20.00%
O&R | Gas | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Authorized return on common equity (percent)	9.20%
Earnings sharing (percent)	9.70%
Common equity ratio (percent)	48.00%
Deferrals for property taxes limitation from rates (percent)	90.00%
O&R | Gas | Year 1 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Base rate changes	$ 0.7
Amortization to income of net regulatory assets	0.8
Potential earnings adjustment mechanism incentives	0.2
Potential Positive Rate Adjustment Gas Safety And Performance Revenue	1.2
Net utility plant reconciliations	720.0
Average rate base	$ 566.0
Weighted average cost of capital (after-tax) (percent)	6.77%
Cost of long-term debt (percent)	4.58%
Requested rate increase (decrease), amount	$ 4.4
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)	$ 6.3
O&R | Gas | Year 2 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Base rate changes	7.4
Amortization to income of net regulatory assets	0.7
Potential earnings adjustment mechanism incentives	0.2
Potential Positive Rate Adjustment Gas Safety And Performance Revenue	1.3
Net utility plant reconciliations	761.0
Average rate base	$ 607.0
Weighted average cost of capital (after-tax) (percent)	6.73%
Cost of long-term debt (percent)	4.51%
Requested rate increase (decrease), amount	$ 4.4
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)	$ 6.7
O&R | Gas | Year 3 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Base rate changes	9.9
Amortization to income of net regulatory assets	0.3
Potential earnings adjustment mechanism incentives	0.4
Potential Positive Rate Adjustment Gas Safety And Performance Revenue	1.4
Net utility plant reconciliations	803.0
Average rate base	$ 649.0
Weighted average cost of capital (after-tax) (percent)	6.72%
Cost of long-term debt (percent)	4.49%
Requested rate increase (decrease), amount	$ 4.4
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)	$ 7.3