Segment Information - Schedule of Revenues by Product (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Revenue from External Customer [Line Items]
Total product revenues, net	$ 3,076.4	$ 2,771.9	$ 8,811.3	$ 8,108.1
Product revenues, net
Revenue from External Customer [Line Items]
Total product revenues, net	3,076.4	2,771.9	8,780.6	8,108.1
TRIKAFTA/KAFTRIO
Revenue from External Customer [Line Items]
Total product revenues, net	2,653.6	2,585.0	7,740.2	7,517.8
ALYFTREK
Revenue from External Customer [Line Items]
Total product revenues, net	247.0	0.0	457.7	0.0
Other product revenues
Revenue from External Customer [Line Items]
Total product revenues, net	$ 175.8	$ 186.9	$ 582.7	$ 590.3