Merger (Details) - Forecast - Merger Agreement - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2023	Dec. 31, 2022
Business Acquisition [Line Items]
Business combination, cash right per common share (in dollars per share)		$ 50.30
Out-of-pocket fees and expenses reimbursement	$ 10.0
PNMR
Business Acquisition [Line Items]
Termination fees	130.0
Avangrid
Business Acquisition [Line Items]
Termination fees	$ 184.0