ASSET RETIREMENT OBLIGATIONS

12 Months Ended

Dec. 31, 2016

Asset Retirement Obligation Disclosure [Abstract]

ASSET RETIREMENT OBLIGATIONS

18. ASSET RETIREMENT OBLIGATIONS

We do not have any assets that are legally restricted for purposes of settling our AROs at December 31, 2016 and 2015. The following is a reconciliation of the beginning and ending aggregate carrying amounts of our ARO liabilities for each of the years ended December 31, 2016 and 2015:

	2016		2015
	(in millions)
Balance at beginning of period	$	103.6	$	96.8
Revisions in estimates		(1.0)		14.1
Accretion expense		4.6		1.5
Liabilities settled		(6.1)		(8.8)
Balance at end of period	$	101.1	$	103.6

ARO liabilities of $1.8 million and $99.3 million are included in “Accounts payable and other” and “Other long-term liabilities,” respectively, on our consolidated statements of financial position. We did not record any AROs for the years ended December 31, 2016 and 2015.