Asset Retirement Obligations (Tables)

3 Months Ended

Mar. 31, 2015

Asset Retirement Obligation Disclosure [Abstract]

Changes in Asset Retirement Obligations

The change in our asset retirement obligations during the three months ended March 31, 2015 is set forth below:

	Three Months Ended March 31, 2015
	(In millions)
Asset retirement obligations as of the beginning of the period, including current portion	$	316.4
Liabilities settled		(17.1	)
Accretion expense		6.4
Asset retirement obligations as of the end of the period, including current portion	$	305.7