Other Consolidated Financial Statement Detail (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Other Income (Expense), Net
Interest income	$ 2.9	$ 2.9
Interest expense	(66.1)	(64.7)
Gains (losses) on investments, net	(191.1)	(436.6)
Foreign exchange gains (losses), net	(8.3)	(8.6)
Other, net	(0.7)	0.1
Total other income (expense), net	(263.3)	(506.9)
Equity Securities, FV-NI, Gain (Loss), Alternative [Abstract]
Net gains (losses) recognized during the period on equity securities	(190.7)	(436.1)
Less: Net gains (losses) realized during the period on equity securities	0.2	6.2
Unrealized gains (losses) recognized during the period on equity securities	(190.9)	$ (442.3)
Accrued Expenses and Other
Revenue-related reserves for discounts and allowances	968.0		$ 935.3
Collaboration expense	206.6		345.1
Royalties and licensing fees	216.0		234.7
Collaboration expense	266.2		324.7
Other	711.2		828.6
Total accrued expense and other	2,231.1		2,535.2
Ionis, Sangamo, Denali and Sage
Equity Securities, FV-NI, Gain (Loss), Alternative [Abstract]
Unrealized gains (losses) recognized during the period on equity securities	205.5
Component of accrued expenses and other
Accrued Expenses and Other
Revenue-related reserves for discounts and allowances	$ 831.1		$ 802.1