Financial Instruments Financial Instruments (Details Textual 2) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Business Acquisition [Line Items]
Proceeds from sales of strategic investments	$ 309.7	$ 0.0
Strategic Investments
Business Acquisition [Line Items]
Strategic investment portfolio	569.8
Ionis Pharmaceuticals
Business Acquisition [Line Items]
Proceeds from sales of strategic investments	213.3
Other current assets | Strategic Investments
Business Acquisition [Line Items]
Strategic investment portfolio	$ 164.2
Other noncurrent assets | Strategic Investments
Business Acquisition [Line Items]
Strategic investment portfolio			$ 676.3