Marketable Securities and Equity Investments - Summary of Cash Equivalents and Marketable Securities (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Cash equivalents
Amortized Cost	$ 5,865.3	$ 7,033.9
Fair Value	5,865.3	7,033.9
Total marketable available-for-sale debt securities
Gross Unrealized Losses	(19.1)
Corporate equity securities
Amortized Cost	72.1	72.1
Gross Unrealized Gains	0.0	0.0
Gross Unrealized Losses	(28.7)	(26.1)
Fair Value	43.4	46.0
Amortized Cost	5,436.3	3,360.8
Gross Unrealized Gains	6.2	15.9
Gross Unrealized Losses	(47.8)	(29.7)
Fair Value	5,394.7	3,347.0
Total cash equivalents and marketable securities, Amortized Cost	11,301.6	10,394.7
Total cash equivalents and marketable securities, Gross Unrealized Gains	6.2	15.9
Total cash equivalents and marketable securities, Gross Unrealized Losses	(47.8)	(29.7)
Total cash equivalents and marketable securities, Fair Value	11,260.0	10,380.9
U.S. Treasury securities
Total marketable available-for-sale debt securities
Amortized Cost	1,395.1	544.5
Gross Unrealized Gains	1.1	3.0
Gross Unrealized Losses	(6.8)	(1.0)
Fair Value	1,389.4	546.5
U.S. government agency securities
Total marketable available-for-sale debt securities
Amortized Cost	357.7	424.8
Gross Unrealized Gains	0.1	0.9
Gross Unrealized Losses	(1.1)	(0.5)
Fair Value	356.7	425.2
Asset-backed securities
Total marketable available-for-sale debt securities
Amortized Cost	793.5	304.9
Gross Unrealized Gains	0.7	1.4
Gross Unrealized Losses	(1.6)	(0.3)
Fair Value	792.6	306.0
Certificates of deposit
Total marketable available-for-sale debt securities
Amortized Cost	42.6	33.7
Gross Unrealized Gains	0.0	0.0
Gross Unrealized Losses	(0.0)	(0.0)
Fair Value	42.6	33.7
Corporate debt securities
Total marketable available-for-sale debt securities
Amortized Cost	2,637.4	1,794.0
Gross Unrealized Gains	4.3	10.5
Gross Unrealized Losses	(9.5)	(1.7)
Fair Value	2,632.2	1,802.8
Commercial paper
Total marketable available-for-sale debt securities
Amortized Cost	137.9	186.8
Gross Unrealized Gains	0.0	0.1
Gross Unrealized Losses	(0.1)	(0.1)
Fair Value	137.8	186.8
Total marketable available-for-sale debt securities
Total marketable available-for-sale debt securities
Amortized Cost	5,364.2	3,288.7
Gross Unrealized Gains	6.2	15.9
Gross Unrealized Losses	(19.1)	(3.6)
Fair Value	$ 5,351.3	$ 3,301.0