Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Cash flows from operating activities:
Net (loss) income	$ (1,448.6)	$ 2,650.8
Adjustments to reconcile net (loss) income to net cash (used in) provided by operating activities:
Stock-based compensation expense	530.7	372.6
Depreciation and amortization expense	160.7	122.3
Deferred income taxes	(400.4)	(405.5)
Loss on equity securities	50.5	0.2
Increase (decrease) in fair value of contingent consideration	0.7	(1.3)
Other non-cash items, net	(16.2)	(9.6)
Changes in operating assets and liabilities:
Accounts receivable, net	(168.3)	(99.5)
Inventories	(369.8)	(252.9)
Prepaid expenses and other assets	(35.7)	(94.4)
Accounts payable	41.1	80.5
Accrued expenses	533.0	786.1
Other liabilities	45.1	153.4
Net cash (used in) provided by operating activities	(1,077.2)	3,302.7
Cash flows from investing activities:
Purchases of available-for-sale debt securities	(5,279.6)	(2,798.0)
Sales and maturities of available-for-sale debt securities	3,005.4	621.0
Acquisition of available-for-sale debt securities from Alpine Immune Sciences, Inc.	(258.0)	0.0
Purchases of property and equipment	(205.1)	(142.3)
Net payments related to finite-lived intangible assets	(187.7)	0.0
Sale of equity securities	0.0	95.1
Other investing activities	(23.1)	(31.0)
Net cash used in investing activities	(2,948.1)	(2,255.2)
Cash flows from financing activities:
Issuances of common stock under benefit plans	80.3	88.2
Repurchases of common stock	(759.2)	(278.1)
Payments in connection with common stock withheld for employee tax obligations	(397.7)	(222.9)
Payments on finance leases	(32.3)	(32.9)
Other financing activities	5.3	3.3
Net cash used in financing activities	(1,103.6)	(442.4)
Effect of changes in exchange rates on cash	4.7	(0.5)
Net (decrease) increase in cash, cash equivalents and restricted cash	(5,124.2)	604.6
Cash, cash equivalents and restricted cash—beginning of period	10,372.3	10,512.0
Cash, cash equivalents and restricted cash—end of period	5,248.1	11,116.6
Supplemental disclosure of cash flow information:
Cash paid for income taxes	810.3	919.1
Cash paid for interest	$ 27.8	$ 32.6