Carryforwards (Details 4) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
State and local jurisdiction
Carryforwards [Line Items]
Operating loss carryforwards	$ 164.8	$ 151.5
Investment tax credit carryforward, amount	35.0	36.3
Federal and State Taxing Authority
Carryforwards [Line Items]
Tax credit carryforward, amount	$ 35.6	$ 37.1