Available-for-Sale Debt Securities (Tables)

12 Months Ended

Dec. 31, 2025

Investments, Debt and Equity Securities [Abstract]

Schedule of Fair Value of Available-For-Sale Debt Securities

The following table presents a summary of available-for-sale debt securities, aggregated by major security type and contractual maturity.


		December 31, 2025								December 31, 2024
(dollars in millions)	Contractual Maturity	Amortized Cost		Unrealized Gain		Unrealized Loss		Fair Value		Amortized Cost		Unrealized Gain		Unrealized Loss		Fair Value
Commercial paper	0 to 1 years	$	22.6	$	—	$	—	$	22.6	$	37.1	$	—	$	—	$	37.1
Corporate debt securities	0 to 1 years	622.6		1.7		—		624.3		527.0		0.6		(0.1)		527.5
Securities of government-sponsored entities	0 to 1 years	120.2		0.3		—		120.5		278.2		0.3		—		278.5
		$	765.4	$	2.0	$	—	$	767.4	$	842.3	$	0.9	$	(0.1)	$	843.1

Corporate debt securities	1 to 3 years	$	945.0	$	4.5	$	(0.5)	$	949.0	$	584.4	$	2.0	$	(1.0)	$	585.4
Securities of government-sponsored entities	1 to 3 years	113.8		0.3		(0.1)		114.0		154.4		0.3		(0.6)		154.1
		$	1,058.8	$	4.8	$	(0.6)	$	1,063.0	$	738.8	$	2.3	$	(1.6)	$	739.5

Schedule of Gross Unrealized Losses and Fair Value Available-For-Sale Investments in Unrealized Loss Position

The following table presents available-for-sale debt securities that were in an unrealized loss position as of December 31, 2025, aggregated by major security type and length of time in a continuous loss position.


	Less Than 12 Months				12 Months or Longer				Total
(in millions)	Fair Value		Unrealized Loss		Fair Value		Unrealized Loss		Fair Value		Unrealized Loss

Corporate debt securities	$	298.2	$	(0.5)	$	—	$	—	$	298.2	$	(0.5)

The following table presents available-for-sale debt securities that were in an unrealized loss position as of December 31, 2024, aggregated by major security type and length of time in a continuous loss position.


	Less Than 12 Months				12 Months or Longer				Total
(in millions)	Fair Value		Unrealized Loss		Fair Value		Unrealized Loss		Fair Value		Unrealized Loss

Corporate debt securities	$	334.9	$	(1.1)	$	—	$	—	$	334.9	$	(1.1)
Securities of government-sponsored entities	$	123.8	$	(0.6)	$	—	$	—	$	123.8	$	(0.6)