Other Consolidated Financial Statement Detail (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Other Income (Expense), Net
Gain on sale of equity interest in Samsung Bioepis(1)	$ 0.0	$ (1,505.4)	$ 0.0	$ (1,505.4)
Litigation settlement agreement	0.0	900.0	0.0	900.0
Interest income	(75.9)	(12.6)	(156.8)	(15.5)
Interest expense	49.1	65.8	111.6	131.9
(Gains) losses on investments, net	(105.4)	78.2	(27.7)	269.3
Foreign exchange (gains) losses, net	8.7	19.2	19.4	27.5
Other, net	2.3	26.2	1.7	26.9
Other (income) expense	(121.2)	(428.6)	(51.8)	(165.3)
Equity Securities, FV-NI, Gain (Loss), Alternative [Abstract]
Net (gains) losses recognized on equity securities	(106.5)	77.2	(28.4)	267.9
Less: Net (gains) losses realized on equity securities	(0.7)	0.7	0.9	0.5
Net unrealized (gains) losses recognized on equity securities	(105.8)	76.5	(29.3)	267.4
Accrued Expenses and Other
Revenue-related reserves for discounts and allowances	1,114.5		1,114.5		$ 1,035.0
Collaboration expense	253.3		253.3		395.6
Royalties and licensing fees	205.0		205.0		209.4
Collaboration expense	332.5		332.5		277.9
Other	725.6		725.6		746.9
Total accrued expense and other	2,481.1		2,481.1		2,521.4
Ionis, Sangamo, Denali and Sage
Equity Securities, FV-NI, Gain (Loss), Alternative [Abstract]
Net unrealized (gains) losses recognized on equity securities	117.7	$ 75.3	78.0	$ 277.1
Component of accrued expenses and other
Accrued Expenses and Other
Revenue-related reserves for discounts and allowances	$ 964.7		$ 964.7		$ 891.6