Financial Instruments (Tables)

3 Months Ended

Mar. 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:

	December 31, 2019				March 31, 2020
	Carrying amount		Fair value		Carrying amount		Fair value
	(In millions)
Cash, cash equivalents and restricted cash	$	392.3	$	392.3	$	342.9	$	342.9
Long-term debt - Fixed rate Senior Notes		442.6		457.0		435.1		374.8
Common stockholders' equity		816.1		1,549.7		782.3		975.1