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Other Consolidated Financial Statement (Details Textual) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Class of Stock [Line Items]
Gain (loss) on investments, net	$ 106.8	$ (173.4)	$ 29.5	$ 203.0
Other long-term liabilities	1,475.4		1,475.4		$ 1,348.9
Accrued income taxes	743.2		743.2		803.3
Net gains recognized on the increase in fair value of equity securities	102.9	(131.3)	42.0	159.5
Proceeds from sale of available-for-sale securities, equity			0.5	$ 309.7
Tax Cuts and Jobs Act, Transition Tax for Accumulated Foreign Earnings, Income Tax Expense			$ 635.0		$ 697.0
Ionis
Class of Stock [Line Items]
Net gains recognized on the increase in fair value of equity securities	67.2
Proceeds from sale of available-for-sale securities, equity		$ 203.0
Sangamo
Class of Stock [Line Items]
Net gains recognized on the increase in fair value of equity securities	$ 40.9