Asset Retirement Obligations (Tables)

12 Months Ended

Dec. 31, 2015

Asset Retirement Obligation Disclosure [Abstract]

Schedule of changes in asset retirement obligations

Changes in asset retirement obligations for the years ended December 31, 2015 and 2014 were as follows:

(In millions)	2015			2014
Balance at beginning of year	$	25.4		$	27.7
Accretion expense	0.6			0.9
Payments	(0.8		)	(2.2		)
Revision of estimates	(0.2		)	(1.0		)
Balance at end of year	$	25.0		$	25.4