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Commitments and Contingencies - Legal Proceedings (Details) $ in Millions	3 Months Ended	6 Months Ended
	Mar. 31, 2026 USD ($)	Jun. 30, 2026 USD ($) lawsuit	Dec. 31, 2025 USD ($)
Loss Contingencies [Line Items]
Finite-lived intangible assets, net		$ 109	$ 45
Arbutus Biopharma Corporation (Arbutus) and Genevant Sciences GmbH (Genevant)
Loss Contingencies [Line Items]
Litigation settlement liability		950
Amount awarded to other party	$ 876
Loss contingency, estimate of possible loss	$ 74
Arbutus Biopharma Corporation (Arbutus) and Genevant Sciences GmbH (Genevant) \| Maximum
Loss Contingencies [Line Items]
Litigation liability		1,300
Arbutus Biopharma Corporation (Arbutus) and Genevant Sciences GmbH (Genevant) \| Intellectual Property
Loss Contingencies [Line Items]
Finite-lived intangible asset, useful life	3 years
Finite-lived intangible assets, net		$ 66
GlaxoSmithKline Biologicals
Loss Contingencies [Line Items]
Number of patent infringement cases \| lawsuit		2