Fair Value Measurements - Schedule of Assets Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Available-for-sale debt securities:
Available-for-sale debt securities	$ 10,018.2	$ 8,397.2
Corporate bonds
Available-for-sale debt securities:
Available-for-sale debt securities	6,684.4	7,487.7
U.S. government and government agency obligations
Available-for-sale debt securities:
Available-for-sale debt securities	2,939.4	108.5
Sovereign bonds
Available-for-sale debt securities:
Available-for-sale debt securities	64.1	64.4
Commercial paper
Available-for-sale debt securities:
Available-for-sale debt securities	121.1	439.6
Certificates of deposit
Available-for-sale debt securities:
Available-for-sale debt securities	182.0	255.1
Asset-backed securities
Available-for-sale debt securities:
Available-for-sale debt securities	27.2	41.9
Measured on a recurring basis
Available-for-sale debt securities:
Total marketable securities	11,228.2	9,647.1
Measured on a recurring basis | Unrestricted
Available-for-sale debt securities:
Equity securities	24.6	58.4
Measured on a recurring basis | Restricted
Available-for-sale debt securities:
Equity securities	1,185.4	1,191.5
Measured on a recurring basis | Corporate bonds
Available-for-sale debt securities:
Available-for-sale debt securities	6,684.4	7,487.7
Measured on a recurring basis | U.S. government and government agency obligations
Available-for-sale debt securities:
Available-for-sale debt securities	2,939.4	108.5
Measured on a recurring basis | Sovereign bonds
Available-for-sale debt securities:
Available-for-sale debt securities	64.1	64.4
Measured on a recurring basis | Commercial paper
Available-for-sale debt securities:
Available-for-sale debt securities	121.1	439.6
Measured on a recurring basis | Certificates of deposit
Available-for-sale debt securities:
Available-for-sale debt securities	182.0	255.1
Measured on a recurring basis | Asset-backed securities
Available-for-sale debt securities:
Available-for-sale debt securities	27.2	41.9
Measured on a recurring basis | Level 1
Available-for-sale debt securities:
Total marketable securities	1,210.0	1,249.9
Measured on a recurring basis | Level 1 | Unrestricted
Available-for-sale debt securities:
Equity securities	24.6	58.4
Measured on a recurring basis | Level 1 | Restricted
Available-for-sale debt securities:
Equity securities	1,185.4	1,191.5
Measured on a recurring basis | Level 1 | Corporate bonds
Available-for-sale debt securities:
Available-for-sale debt securities	0.0	0.0
Measured on a recurring basis | Level 1 | U.S. government and government agency obligations
Available-for-sale debt securities:
Available-for-sale debt securities	0.0	0.0
Measured on a recurring basis | Level 1 | Sovereign bonds
Available-for-sale debt securities:
Available-for-sale debt securities	0.0	0.0
Measured on a recurring basis | Level 1 | Commercial paper
Available-for-sale debt securities:
Available-for-sale debt securities	0.0	0.0
Measured on a recurring basis | Level 1 | Certificates of deposit
Available-for-sale debt securities:
Available-for-sale debt securities	0.0	0.0
Measured on a recurring basis | Level 1 | Asset-backed securities
Available-for-sale debt securities:
Available-for-sale debt securities	0.0	0.0
Measured on a recurring basis | Level 2
Available-for-sale debt securities:
Total marketable securities	10,018.2	8,397.2
Measured on a recurring basis | Level 2 | Unrestricted
Available-for-sale debt securities:
Equity securities	0.0	0.0
Measured on a recurring basis | Level 2 | Restricted
Available-for-sale debt securities:
Equity securities	0.0	0.0
Measured on a recurring basis | Level 2 | Corporate bonds
Available-for-sale debt securities:
Available-for-sale debt securities	6,684.4	7,487.7
Measured on a recurring basis | Level 2 | U.S. government and government agency obligations
Available-for-sale debt securities:
Available-for-sale debt securities	2,939.4	108.5
Measured on a recurring basis | Level 2 | Sovereign bonds
Available-for-sale debt securities:
Available-for-sale debt securities	64.1	64.4
Measured on a recurring basis | Level 2 | Commercial paper
Available-for-sale debt securities:
Available-for-sale debt securities	121.1	439.6
Measured on a recurring basis | Level 2 | Certificates of deposit
Available-for-sale debt securities:
Available-for-sale debt securities	182.0	255.1
Measured on a recurring basis | Level 2 | Asset-backed securities
Available-for-sale debt securities:
Available-for-sale debt securities	$ 27.2	$ 41.9