Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2020

Fair Value Disclosures [Abstract]

Financial Instruments not Carried at Fair Value but which Require Fair Value Disclosure

The following table presents the financial instruments that are not carried at fair value but which require fair value disclosure as of December 31, 2019 and 2020.

		December 31, 2019				December 31, 2020
		Carrying amount		Fair value		Carrying amount		Fair value
	(In millions)
Cash, cash equivalents and restricted cash		$	392.3	$	392.3	$	362.0	$	362.0
Long-term debt - Fixed rate Senior Notes			442.6		457.0		485.7		499.9