Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2017

Goodwill and Intangible Assets Disclosure [Abstract]

Intangible assets

Intangible assets, which are included in Other assets, consist of the following:

(In millions)	At December 31,
	2017				2016
	Amortizing		Non-amortizing		Amortizing		Non-amortizing
Customer-related assets	$	18.6	$	—	$	20.9	$	—
Market-related assets	6.6		6.0		—		13.0
Intangible assets, net	$	25.2	$	6.0	$	20.9	$	13.0