Asset Retirement Obligations (Tables)

3 Months Ended

Mar. 31, 2016

Asset Retirement Obligation Disclosure [Abstract]

Changes in Asset Retirement Obligations

The change in our asset retirement obligations during the three months ended March 31, 2016 is set forth below:

	Three Months Ended March 31, 2016
	(In millions)
Asset retirement obligations as of the beginning of the period, including current portion	$	225.9
Liabilities incurred	2.1
Liabilities settled	(4.7		)
Accretion expense	10.0
Asset retirement obligations as of the end of the period, including current portion	$	233.3