Note 9. Income Taxes Unrecognized Tax Benefit (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Unrecognized Tax Benefits	$ 2.3	$ 2.3	$ 8.1	$ 7.0
Unrecognized Tax Benefits, Increase Resulting from Prior Period Tax Positions	0.0	0.0	3.0
Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions	0.0	0.0	(0.3)
Unrecognized Tax Benefits, Decrease Resulting from Settlements with Taxing Authorities	0.0	(5.8)	(1.5)
Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations	0.0	0.0	(0.1)
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	4.1	4.0
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued	2.9	2.7
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense	$ 0.2	$ (1.0)	$ 0.5