Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2023

Fair Value Disclosures [Abstract]

Schedule of Fair Value, Assets Measured on Recurring and Nonrecurring Basis

The table below summarizes the valuation of our financial instruments carried at fair value by the applicable pricing categories (in millions):

	Year Ended
	December 31, 2023						December 31, 2022
	Level 1		Level 2		Level 3		Level 1		Level 2		Level 3
Measured at fair value on a recurring basis:
Assets:
Investment securities	$	0.1	$	—	$	—	$	0.1	$	—	$	—
Foreign currency forward contracts	—		0.6		—		—		4.2		—
Interest rate swap agreements	—		30.5		—		—		50.5		—
Total assets	$	0.1	$	31.1	$	—	$	0.1	$	54.7	$	—
Liabilities:
Foreign currency forward contracts	$	—	$	2.7	$	—	$	—	$	5.2	$	—
Cross-currency swap	—		172.0		—		—		96.1		—
Interest rate swap agreements	—		11.7		—		—		—		—
Total liabilities	$	—	$	186.4	$	—	$	—	$	101.3	$	—
Measured at fair value on a non-recurring basis:
Assets:
Goodwill(1)	$	—	$	—	$	118.9	$	—	$	—	$	—
Total assets	$	—	$	—	$	118.9	$	—	$	—	$	—

(1) During the year ended December 31, 2023, goodwill within our Rare Diseases reporting unit with a carrying value of $208.9 million was written down to a fair value of $118.9 million.

Schedule of Long-Term Debt Fair Value

Our fixed rate long-term debt consisted of the following (in millions):

	Year Ended
	December 31, 2023				December 31, 2022
	Level 1		Level 2		Level 1		Level 2
Public Bonds
Carrying value (excluding discount)	$	2,244.4	$	—	$	2,544.4	$	—
Fair Value	$	2,062.2	$	—	$	2,225.4	$	—