Note 3. Derivative Instruments and Fair Value Measurements Derivatives - FX Hedge (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Derivative [Line Items]
Total stockholders' equity		$ 2,016.0	$ 2,378.9	$ 2,562.0	$ 4,858.0
Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member]
Derivative [Line Items]
Derivative, Notional Amount		30.0
Derivative Asset		(4.8)
Designated as Hedging Instrument [Member] | Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] | Foreign Exchange Contract [Member]
Derivative [Line Items]
Total stockholders' equity		(7.3)
Designated as Hedging Instrument [Member] | Interest Expense [Member] | Foreign Exchange Contract [Member]
Derivative [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net		3.2	$ 0.1
Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net	[1]	$ (7.3)

[1] Based on the fair value of open hedges as of December 31, 2020