Carryforwards (Details 4) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
State and local jurisdiction
Carryforwards [Line Items]
Operating loss carryforwards	$ 176.0	$ 164.8
Investment tax credit carryforward, amount	35.1	35.0
Federal and State Taxing Authority
Carryforwards [Line Items]
Tax credit carryforward, amount	$ 35.7	$ 35.6