Regulatory Matters - MISO Return on Equity Complaints (Details) - FERC [Member]	Dec. 31, 2020	Dec. 31, 2019
Loss Contingencies [Line Items]
FERC Authorized Return on Common Equity	10.02%	9.88%
FERC Authorized Return on Equity Including Incentive Adder	10.52%	10.38%