Regulatory Matters - Rate Plans (Details) - Scenario, Forecast - O&R - NYSPSC $ in Millions	1 Months Ended
	Jan. 31, 2019 USD ($)
Electric
Public Utilities, General Disclosures [Line Items]
Increase (decrease) in requested rate increase	$ 2.2
Requested rate increase, amount	22.5
Gas
Public Utilities, General Disclosures [Line Items]
Increase (decrease) in requested rate increase	(1.7)
Requested rate increase, amount	$ 2.7