Equity Method Investment (Details) - NMRD $ in Millions	9 Months Ended
	Sep. 30, 2020 USD ($) MW	Sep. 30, 2019 USD ($)
Business Acquisition [Line Items]
Renewable energy capacity in operating (in mw) | MW	135.1
PNMR Development
Business Acquisition [Line Items]
Ownership percentage	50.00%
Contribution to construction activities | $	$ 23.3	$ 29.3