Fair Value Measurements - Schedule of Assets Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Millions	Sep. 30, 2025	Dec. 31, 2024
Assets, Fair Value Disclosure [Abstract]
Available-for-sale debt securities	$ 15,522.1	$ 14,329.1
Corporate bonds
Assets, Fair Value Disclosure [Abstract]
Available-for-sale debt securities	9,697.7	8,220.6
U.S. government and government agency obligations
Assets, Fair Value Disclosure [Abstract]
Available-for-sale debt securities	4,703.3	4,817.0
Commercial paper
Assets, Fair Value Disclosure [Abstract]
Available-for-sale debt securities	445.3	548.7
Certificates of deposit
Assets, Fair Value Disclosure [Abstract]
Available-for-sale debt securities	310.4	381.1
Asset-backed securities
Assets, Fair Value Disclosure [Abstract]
Available-for-sale debt securities	295.2	279.3
Sovereign bonds
Assets, Fair Value Disclosure [Abstract]
Available-for-sale debt securities	70.2	82.4
Measured on a recurring basis
Assets, Fair Value Disclosure [Abstract]
Cash equivalents	1,162.5	1,452.2
Equity securities	700.8	1,095.3
Total assets	17,385.4	16,876.6
Liabilities, Fair Value Disclosure [Abstract]
Contingent consideration	10.3	52.3
Measured on a recurring basis | Restricted
Assets, Fair Value Disclosure [Abstract]
Equity securities	63.9	43.2
Measured on a recurring basis | Corporate bonds
Assets, Fair Value Disclosure [Abstract]
Available-for-sale debt securities	9,697.7	8,220.6
Measured on a recurring basis | U.S. government and government agency obligations
Assets, Fair Value Disclosure [Abstract]
Available-for-sale debt securities	4,703.3	4,817.0
Measured on a recurring basis | Commercial paper
Assets, Fair Value Disclosure [Abstract]
Available-for-sale debt securities	445.3	548.7
Measured on a recurring basis | Certificates of deposit
Assets, Fair Value Disclosure [Abstract]
Available-for-sale debt securities	310.4	381.1
Measured on a recurring basis | Asset-backed securities
Assets, Fair Value Disclosure [Abstract]
Available-for-sale debt securities	295.2	279.3
Measured on a recurring basis | Sovereign bonds
Assets, Fair Value Disclosure [Abstract]
Available-for-sale debt securities	70.2	82.4
Measured on a recurring basis | Level 1
Assets, Fair Value Disclosure [Abstract]
Cash equivalents	378.3	1,264.2
Equity securities	700.8	1,095.3
Total assets	1,079.1	2,359.5
Liabilities, Fair Value Disclosure [Abstract]
Contingent consideration	0.0	0.0
Measured on a recurring basis | Level 1 | Corporate bonds
Assets, Fair Value Disclosure [Abstract]
Available-for-sale debt securities	0.0	0.0
Measured on a recurring basis | Level 1 | U.S. government and government agency obligations
Assets, Fair Value Disclosure [Abstract]
Available-for-sale debt securities	0.0	0.0
Measured on a recurring basis | Level 1 | Commercial paper
Assets, Fair Value Disclosure [Abstract]
Available-for-sale debt securities	0.0	0.0
Measured on a recurring basis | Level 1 | Certificates of deposit
Assets, Fair Value Disclosure [Abstract]
Available-for-sale debt securities	0.0	0.0
Measured on a recurring basis | Level 1 | Asset-backed securities
Assets, Fair Value Disclosure [Abstract]
Available-for-sale debt securities	0.0	0.0
Measured on a recurring basis | Level 1 | Sovereign bonds
Assets, Fair Value Disclosure [Abstract]
Available-for-sale debt securities	0.0	0.0
Measured on a recurring basis | Level 2
Assets, Fair Value Disclosure [Abstract]
Cash equivalents	784.2	188.0
Equity securities	0.0	0.0
Total assets	16,306.3	14,517.1
Liabilities, Fair Value Disclosure [Abstract]
Contingent consideration	0.0	0.0
Measured on a recurring basis | Level 2 | Corporate bonds
Assets, Fair Value Disclosure [Abstract]
Available-for-sale debt securities	9,697.7	8,220.6
Measured on a recurring basis | Level 2 | U.S. government and government agency obligations
Assets, Fair Value Disclosure [Abstract]
Available-for-sale debt securities	4,703.3	4,817.0
Measured on a recurring basis | Level 2 | Commercial paper
Assets, Fair Value Disclosure [Abstract]
Available-for-sale debt securities	445.3	548.7
Measured on a recurring basis | Level 2 | Certificates of deposit
Assets, Fair Value Disclosure [Abstract]
Available-for-sale debt securities	310.4	381.1
Measured on a recurring basis | Level 2 | Asset-backed securities
Assets, Fair Value Disclosure [Abstract]
Available-for-sale debt securities	295.2	279.3
Measured on a recurring basis | Level 2 | Sovereign bonds
Assets, Fair Value Disclosure [Abstract]
Available-for-sale debt securities	70.2	82.4
Measured on a recurring basis | Level 3
Assets, Fair Value Disclosure [Abstract]
Cash equivalents	0.0	0.0
Equity securities	0.0	0.0
Total assets	0.0	0.0
Liabilities, Fair Value Disclosure [Abstract]
Contingent consideration	10.3	52.3
Measured on a recurring basis | Level 3 | Corporate bonds
Assets, Fair Value Disclosure [Abstract]
Available-for-sale debt securities	0.0	0.0
Measured on a recurring basis | Level 3 | U.S. government and government agency obligations
Assets, Fair Value Disclosure [Abstract]
Available-for-sale debt securities	0.0	0.0
Measured on a recurring basis | Level 3 | Commercial paper
Assets, Fair Value Disclosure [Abstract]
Available-for-sale debt securities	0.0	0.0
Measured on a recurring basis | Level 3 | Certificates of deposit
Assets, Fair Value Disclosure [Abstract]
Available-for-sale debt securities	0.0	0.0
Measured on a recurring basis | Level 3 | Asset-backed securities
Assets, Fair Value Disclosure [Abstract]
Available-for-sale debt securities	0.0	0.0
Measured on a recurring basis | Level 3 | Sovereign bonds
Assets, Fair Value Disclosure [Abstract]
Available-for-sale debt securities	$ 0.0	$ 0.0