Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024
Cash flows from operating activities:
Net income (loss)	$ 2,762.1	$ (1,448.6)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Stock-based compensation expense	528.3	530.7
Depreciation and amortization expense	154.1	160.7
Intangible asset impairment charge	379.0	0.0
Deferred income taxes	(541.3)	(400.4)
Losses on equity securities	12.2	50.5
Other non-cash items, net	90.3	(15.5)
Changes in operating assets and liabilities:
Accounts receivable	(247.9)	(168.3)
Inventories	(446.8)	(369.8)
Prepaid expenses and other assets	(145.4)	(35.7)
Accounts payable	(1.5)	41.1
Accrued expenses	547.6	533.0
Other liabilities	42.7	45.1
Net cash provided by (used in) operating activities	3,133.4	(1,077.2)
Cash flows from investing activities:
Purchases of available-for-sale debt securities	(5,165.9)	(5,279.6)
Sales and maturities of available-for-sale debt securities	4,805.6	3,005.4
Acquisition of available-for-sale debt securities from Alpine Immune Sciences, Inc.	0.0	(258.0)
Purchases of property and equipment	(288.2)	(205.1)
Net payments related to finite-lived intangible assets	0.0	(187.7)
Other investing activities	(8.8)	(23.1)
Net cash used in investing activities	(657.3)	(2,948.1)
Cash flows from financing activities:
Issuances of common stock under benefit plans	73.7	80.3
Repurchases of common stock	(1,889.0)	(759.2)
Payments in connection with common stock withheld for employee tax obligations	(367.4)	(397.7)
Payments on finance leases	(4.0)	(32.3)
Other financing activities	2.6	5.3
Net cash used in financing activities	(2,184.1)	(1,103.6)
Effect of changes in exchange rates on cash	83.6	4.7
Net increase (decrease) in cash, cash equivalents and restricted cash	375.6	(5,124.2)
Cash, cash equivalents and restricted cash—beginning of period	4,572.2	10,372.3
Cash, cash equivalents and restricted cash—end of period	4,947.8	5,248.1
Supplemental disclosure of cash flow information:
Cash paid for income taxes	1,177.3	810.3
Cash paid for interest	$ 9.4	$ 27.8