v3.25.1
Investments (Tables)
 3 Months Ended
Mar. 31, 2025
Investments [Abstract]  
Schedule of Available-for-Sale Debt Securities
Available-for-sale debt securities are recorded at fair value, with the portion of the unrealized gains and losses that are not credit-related included as a component of accumulated other comprehensive loss in stockholders’ equity, until realized. Available-for-sale debt securities consisted of the following (in millions):
As of March 31, 2025Amortized
Cost		Gross
Unrealized
Gains		Gross
Unrealized
Losses		Fair
Value
U.S. government and agency securities$2,681.0 $6.8 $(1.1)$2,686.7 
Corporate debt securities586.8 2.5 (0.1)589.2 
Total
$3,267.8 $9.3 $(1.2)$3,275.9 
Reported under the following captions in our consolidated balance sheets:
Cash and cash equivalents$162.4 
Current marketable investments  1,402.8 
Non-current marketable investments  1,710.7 
Total
  $3,275.9 
As of December 31, 2024Amortized
Cost		Gross
Unrealized
Gains		Gross
Unrealized
Losses		Fair
Value
U.S. government and agency securities$2,473.7 $3.1 $(3.5)$2,473.3 
Corporate debt securities568.0 1.9 (0.5)569.4 
Total
$3,041.7 $5.0 $(4.0)$3,042.7 
Reported under the following captions in our consolidated balance sheets:
Cash and cash equivalents$21.5 
Current marketable investments  1,545.9 
Non-current marketable investments  1,475.3 
Total
  $3,042.7 
Schedule of Available-for-Sale Debt Securities in an Unrealized Loss Position
The following tables present gross unrealized losses and fair value for those available-for-sale debt securities that were in an unrealized loss position as of March 31, 2025 and December 31, 2024, aggregated by investment category and length of time that the individual securities have been in a continuous loss position (in millions):

Less than 12 months12 months or longerTotal
As of March 31, 2025Fair ValueGross
Unrealized
Losses		Fair ValueGross
Unrealized
Losses		Fair ValueGross
Unrealized
Losses
U.S. government and agency securities$708.6 $(1.0)$146.5 $(0.1)$855.1 $(1.1)
Corporate debt securities48.9 (0.1)22.0 — 70.9 (0.1)
Total$757.5 $(1.1)$168.5 $(0.1)$926.0 $(1.2)

Less than 12 months12 months or longerTotal
As of December 31, 2024Fair ValueGross
Unrealized
Losses		Fair ValueGross
Unrealized
Losses		Fair ValueGross
Unrealized
Losses
U.S. government and agency securities$947.3 $(3.3)$341.1 $(0.2)$1,288.4 $(3.5)
Corporate debt securities75.0 (0.2)82.0 (0.3)157.0 (0.5)
Total$1,022.3 $(3.5)$423.1 $(0.5)$1,445.4 $(4.0)
Schedule of the Contractual Maturities
The following table summarizes the contractual maturities of available-for-sale debt securities (in millions). Actual maturities may differ from contractual maturities because the issuers of certain of these debt securities have the right to call the securities or prepay their obligations under the securities with or without penalties.
 As of March 31, 2025
 Amortized CostFair Value
Due within one year$1,564.5 $1,565.2 
Due in one to three years1,703.3 1,710.7 
Total$3,267.8 $3,275.9