Note 11. Employee Retirement Plans Accumulated Benefit Obligations and Funded Status (Details) - Supplemental Executive Retirement Plan (SERP) [Member] - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Defined Benefit Plan, Plan Assets, Category [Line Items]
Liability, Defined Benefit Plan	$ (11.1)	$ (11.2)
Defined Benefit Plan, Funded (Unfunded) Status of Plan	$ (11.1)	$ (11.2)