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Financial Instruments and Fair Value - Fair Value Measurements (Details) - USD ($) $ in Millions	Jun. 30, 2025	Dec. 31, 2024
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 1,222.4	$ 1,126.4
Marketable equity securities	84.0	64.2
Fair Value	1,306.4	1,190.6
U.S. government and agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	514.5	469.5
Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	433.1	428.7
Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	177.5	166.4
Certificates of deposit and term deposits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	97.3	61.8
Recurring Basis | Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	1,596.4	1,546.4
Recurring Basis | Fair Value | Cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	290.0	355.8
Recurring Basis | Fair Value | Short term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	1,194.4	1,190.6
Recurring Basis | Fair Value | Long-term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	112.0	0.0
Recurring Basis | Fair Value | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	841.4	824.8
Recurring Basis | Fair Value | Level 1 | Cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	251.7	296.1
Recurring Basis | Fair Value | Level 1 | Short term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	534.5	528.7
Recurring Basis | Fair Value | Level 1 | Long-term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	55.2	0.0
Recurring Basis | Fair Value | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	755.0	721.6
Recurring Basis | Fair Value | Level 2 | Cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	38.3	59.7
Recurring Basis | Fair Value | Level 2 | Short term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	659.9	661.9
Recurring Basis | Fair Value | Level 2 | Long-term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	56.8	0.0
Recurring Basis | Fair Value | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	0.0	0.0
Recurring Basis | Fair Value | Level 3 | Cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0.0	0.0
Recurring Basis | Fair Value | Level 3 | Short term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0.0	0.0
Recurring Basis | Fair Value | Level 3 | Long-term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0.0	0.0
Recurring Basis | Fair Value | Money market funds | Cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	251.7	296.1
Recurring Basis | Fair Value | Money market funds | Level 1 | Cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	251.7	296.1
Recurring Basis | Fair Value | Money market funds | Level 2 | Cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0.0	0.0
Recurring Basis | Fair Value | Money market funds | Level 3 | Cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0.0	0.0
Recurring Basis | Fair Value | Commercial paper | Cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	36.3	59.7
Recurring Basis | Fair Value | Commercial paper | Level 1 | Cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0.0	0.0
Recurring Basis | Fair Value | Commercial paper | Level 2 | Cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	36.3	59.7
Recurring Basis | Fair Value | Commercial paper | Level 3 | Cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0.0	0.0
Recurring Basis | Fair Value | U.S. government and agency securities | Short term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	454.0	469.5
Recurring Basis | Fair Value | U.S. government and agency securities | Long-term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	60.5	0.0
Recurring Basis | Fair Value | U.S. government and agency securities | Level 1 | Short term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	450.5	464.5
Recurring Basis | Fair Value | U.S. government and agency securities | Level 1 | Long-term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	55.2	0.0
Recurring Basis | Fair Value | U.S. government and agency securities | Level 2 | Short term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	3.5	5.0
Recurring Basis | Fair Value | U.S. government and agency securities | Level 2 | Long-term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	5.3	0.0
Recurring Basis | Fair Value | U.S. government and agency securities | Level 3 | Short term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0.0	0.0
Recurring Basis | Fair Value | U.S. government and agency securities | Level 3 | Long-term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0.0	0.0
Recurring Basis | Fair Value | Commercial paper | Short term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	433.1	428.7
Recurring Basis | Fair Value | Commercial paper | Level 1 | Short term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0.0	0.0
Recurring Basis | Fair Value | Commercial paper | Level 2 | Short term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	433.1	428.7
Recurring Basis | Fair Value | Commercial paper | Level 3 | Short term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0.0	0.0
Recurring Basis | Fair Value | Corporate debt securities | Cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	2.0	0.0
Recurring Basis | Fair Value | Corporate debt securities | Short term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	126.0	166.4
Recurring Basis | Fair Value | Corporate debt securities | Long-term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	51.5	0.0
Recurring Basis | Fair Value | Corporate debt securities | Level 1 | Cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0.0	0.0
Recurring Basis | Fair Value | Corporate debt securities | Level 1 | Short term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0.0	0.0
Recurring Basis | Fair Value | Corporate debt securities | Level 1 | Long-term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0.0	0.0
Recurring Basis | Fair Value | Corporate debt securities | Level 2 | Cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	2.0	0.0
Recurring Basis | Fair Value | Corporate debt securities | Level 2 | Short term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	126.0	166.4
Recurring Basis | Fair Value | Corporate debt securities | Level 2 | Long-term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	51.5	0.0
Recurring Basis | Fair Value | Corporate debt securities | Level 3 | Cash equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0.0	0.0
Recurring Basis | Fair Value | Corporate debt securities | Level 3 | Short term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0.0	0.0
Recurring Basis | Fair Value | Corporate debt securities | Level 3 | Long-term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0.0	0.0
Recurring Basis | Fair Value | Certificates of deposit and term deposits | Short term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	97.3	61.8
Recurring Basis | Fair Value | Certificates of deposit and term deposits | Level 1 | Short term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0.0	0.0
Recurring Basis | Fair Value | Certificates of deposit and term deposits | Level 2 | Short term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	97.3	61.8
Recurring Basis | Fair Value | Certificates of deposit and term deposits | Level 3 | Short term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0.0	0.0
Recurring Basis | Fair Value | Marketable equity securities | Short term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable equity securities	84.0	64.2
Recurring Basis | Fair Value | Marketable equity securities | Level 1 | Short term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable equity securities	84.0	64.2
Recurring Basis | Fair Value | Marketable equity securities | Level 2 | Short term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable equity securities	0.0	0.0
Recurring Basis | Fair Value | Marketable equity securities | Level 3 | Short term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable equity securities	$ 0.0	$ 0.0

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