Cash, Cash Equivalents, and Marketable Debt Securities - Schedule of Company's Cash and Available-For-Sale (AFS) Debt Securities by Major Asset Category (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2023		Dec. 31, 2022
Financial Instruments [Line Items]
Adjusted Cost Basis		$ 1,205.8		$ 472.7
Unrealized Gain		0.3		0.0
Unrealized Loss		(0.5)		(2.6)
Fair Value		1,205.6		470.1
Cash and Cash Equivalents		648.0		320.0
Short-Term Marketable Debt Securities		493.5		85.2
Long-Term Marketable Debt Securities		64.1		64.9
Level 1
Financial Instruments [Line Items]
Adjusted Cost Basis	[1]	30.9		24.4
Unrealized Gain	[1]	0.0		0.0
Unrealized Loss	[1]	0.0		(0.4)
Fair Value	[1]	30.9		24.0
Cash and Cash Equivalents	[1]	1.6		0.1
Short-Term Marketable Debt Securities	[1]	11.3		16.7
Long-Term Marketable Debt Securities	[1]	18.0		7.2
Level 2
Financial Instruments [Line Items]
Adjusted Cost Basis	[2]	128.5		130.0
Unrealized Gain	[2]	0.3	[1]	0.0
Unrealized Loss	[2]	(0.5)		(2.2)
Fair Value	[2]	128.3		127.8
Cash and Cash Equivalents	[2]	0.0		1.6
Short-Term Marketable Debt Securities	[2]	82.2		68.5
Long-Term Marketable Debt Securities	[2]	46.1		57.7
U.S. Government Agency Securities | Level 2
Financial Instruments [Line Items]
Adjusted Cost Basis	[2]	10.1		4.5
Unrealized Gain	[2]	0.0		0.0
Unrealized Loss	[2]	(0.1)		0.1
Fair Value	[2]	10.0		4.4
Cash and Cash Equivalents	[2]	0.0		0.0
Short-Term Marketable Debt Securities	[2]	7.8		1.2
Long-Term Marketable Debt Securities	[2]	2.2		3.2
Corporate Debt Securities | Level 2
Financial Instruments [Line Items]
Adjusted Cost Basis	[2]	112.5		123.9
Unrealized Gain	[2]	0.3		0.0
Unrealized Loss	[2]	(0.4)		(2.1)
Fair Value	[2]	112.4		121.8
Cash and Cash Equivalents	[2]	0.0		1.6
Short-Term Marketable Debt Securities	[2]	68.5		65.7
Long-Term Marketable Debt Securities	[2]	43.9		54.5
Cash and Cash Equivalents
Financial Instruments [Line Items]
Adjusted Cost Basis		646.4		318.3
Unrealized Gain		0.0		0.0
Unrealized Loss		0.0		0.0
Fair Value		646.4		318.3
Cash and Cash Equivalents		646.4		318.3
Short-Term Marketable Debt Securities		0.0		0.0
Long-Term Marketable Debt Securities		0.0		0.0
Time Deposits
Financial Instruments [Line Items]
Adjusted Cost Basis	[3]	400.0
Unrealized Gain	[3]	0.0
Unrealized Loss	[3]	0.0
Fair Value	[3]	400.0
Cash and Cash Equivalents	[3]	0.0
Short-Term Marketable Debt Securities	[3]	400.0
Long-Term Marketable Debt Securities	[3]	0.0
Money Market Fund | Level 1
Financial Instruments [Line Items]
Adjusted Cost Basis	[1]	1.6		0.1
Unrealized Gain	[1]	0.0		0.0
Unrealized Loss	[1]	0.0		0.0
Fair Value	[1]	1.6		0.1
Cash and Cash Equivalents	[1]	1.6		0.1
Short-Term Marketable Debt Securities	[1]	0.0		0.0
Long-Term Marketable Debt Securities	[1]	0.0		0.0
U.S. Treasury Securities | Level 1
Financial Instruments [Line Items]
Adjusted Cost Basis	[1]	29.3		24.3
Unrealized Gain	[1]	0.0		0.0
Unrealized Loss	[1]	0.0		(0.4)
Fair Value	[1]	29.3		23.9
Cash and Cash Equivalents	[1]	0.0		0.0
Short-Term Marketable Debt Securities	[1]	11.3		16.7
Long-Term Marketable Debt Securities	[1]	18.0		7.2
Certificates of Deposit | Level 2
Financial Instruments [Line Items]
Adjusted Cost Basis	[2]	5.9		1.6
Unrealized Gain	[2]	0.0		0.0
Unrealized Loss	[2]	0.0		0.0
Fair Value	[2]	5.9		1.6
Cash and Cash Equivalents	[2]	0.0		0.0
Short-Term Marketable Debt Securities	[2]	5.9		1.6
Long-Term Marketable Debt Securities	[2]	$ 0.0		$ 0.0

[1] Valuations based on quoted prices for identical assets and liabilities in active markets.

[2] Valuations based on observable inputs other than quoted prices included in Level 1, such as quoted prices for similar assets and liabilities in active markets, quoted prices for identical or similar assets and liabilities in markets that are not active, or other inputs that are observable or can be corroborated by observable market data.

[3] We had $400.0 million of investments in time deposits classified as HTM debt securities as of December 31, 2023. All these investments mature within one year and are recorded in “Short-term marketable debt securities” on our Consolidated Balance Sheets. We record HTM debt securities at amortized cost, which approximates fair value. We did not have any investments classified as HTM debt securities as of December 31, 2022.