Segment Information - Schedule of Significant Segment Expenses (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Segment Reporting Information [Line Items]
Product revenues, net	$ 11,020.1	$ 9,869.2	$ 8,930.7
Cost of sales	1,530.5	1,262.2	1,080.3
Acquired in-process research and development expenses	4,628.4	527.1	115.5
Interest income	(598.1)	(614.7)	(144.6)
Provision for income taxes	784.1	760.2	910.4
Net (loss) income	(535.6)	3,619.6	3,322.0
Pharmaceuticals
Segment Reporting Information [Line Items]
Product revenues, net	11,020.1	9,869.2	8,930.7
Research expenses	804.5	705.6	626.7
Development expenses	2,825.8	2,457.3	1,913.6
Acquired in-process research and development expenses	4,628.4	527.1	115.5
Selling and other commercial expenses	838.5	592.4	468.9
General and administrative expenses	625.8	544.2	475.8
Interest income	(598.1)	(614.7)	(144.6)
Other Segment items	116.2	15.3	162.1
Provision for income taxes	784.1	760.2	910.4
Net (loss) income	(535.6)	3,619.6	3,322.0
Products | Pharmaceuticals
Segment Reporting Information [Line Items]
Cost of sales	516.3	349.2	260.5
Royalty | Pharmaceuticals
Segment Reporting Information [Line Items]
Cost of sales	$ 1,014.2	$ 913.0	$ 819.8