Investment in ATC and ATC Holdco (Details-3) - ATC [Member] - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Related Party Transaction [Line Items]
Related party expenses	$ 7.8	$ 8.0	$ 15.7	$ 16.0
Due from related parties	$ 3.1		$ 3.1		$ 7.0

For an unclassified balance sheet, amounts due from related parties including affiliates, employees, joint ventures, officers and stockholders, immediate families thereof, and pension funds.

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+ Details