Asset Retirement Obligations (Tables)

6 Months Ended

Jun. 30, 2016

Asset Retirement Obligation Disclosure [Abstract]

Changes in Asset Retirement Obligations

The change in our asset retirement obligations during the six months ended June 30, 2016 is set forth below:

	Six Months Ended June 30, 2016
	(In millions)
Asset retirement obligations as of the beginning of the period, including current portion	$	225.9
Liabilities incurred	2.1
Liabilities settled	(10.7		)
Accretion expense	20.1
Asset retirement obligations as of the end of the period, including current portion	$	237.4