Income Taxes - Additional Information (Details) - USD ($) $ in Millions		12 Months Ended
	May 20, 2024	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Tax Carryforwards [Line Items]
Effective tax rate		315.50%	17.40%	21.50%
Valuation allowance		$ 272.9	$ 266.6
Deferred costs		279.3	185.8
Increase in unrecognized tax benefits		90.3	156.3	$ 312.4
Unrecognized tax benefits, increase (decrease) in deferred tax assets, gross		1.6	3.7	(29.7)
Unrecognized tax benefits, deferred tax liabilities, gross		91.9	160.0	282.7
Unrecognized tax benefits		706.2	615.9	459.6	$ 147.2
Net unrecognized tax benefits which would affect the tax rate if recognized		341.4	288.7	208.5
Unrecognized tax benefits, income tax penalties and interest expense (credit)		(41.5)	84.9	$ 36.6
Unrecognized tax benefits, income tax penalties and interest accrued		82.6	$ 124.1
Decrease in unrecognized tax benefits is reasonably possible		74.3
Alpine Immune Sciences Inc
Tax Carryforwards [Line Items]
Acquired in-process research and development expense	$ 4,423.2	4,400.0
Deferred tax assets
Tax Carryforwards [Line Items]
Unrecognized tax benefits		48.2
Accrued expenses
Tax Carryforwards [Line Items]
Unrecognized tax benefits		22.3
Other long-term liabilities
Tax Carryforwards [Line Items]
Unrecognized tax benefits		635.7
Domestic Tax Jurisdiction
Tax Carryforwards [Line Items]
Operating loss carryforwards		152.3
Operating loss carryforwards, subject to expiration		19.5
State and Local Jurisdiction
Tax Carryforwards [Line Items]
Operating loss carryforwards		463.8
Tax credit carryforwards		380.1
Foreign Tax Jurisdiction
Tax Carryforwards [Line Items]
Operating loss carryforwards		40.2
Operating loss carryforwards, subject to expiration		17.9
Tax credit carryforwards		$ 8.3