Note 10 Asset Retirement Obligations

U.S. Cellular is subject to asset retirement obligations associated with its leased cell sites, switching office sites, retail store sites and office locations in its operating markets. Asset retirement obligations generally include obligations to restore leased land and retail store and office premises to their pre-lease conditions. These obligations are included in Other deferred liabilities and credits in the Consolidated Balance Sheet.

In 2016 and 2015, U.S. Cellular performed a review of the assumptions and estimated costs related to its asset retirement obligations. The results of the reviews (identified as “Revisions in estimated cash outflows”) and other changes in asset retirement obligations during 2016 and 2015 were as follows:

		2016		2015
(Dollars in millions)
Balance at beginning of year		$	158	$	152
	Additional liabilities accrued		1		2
	Revisions in estimated cash outflows		5		(1)
	Disposition of assets		(1)		(6)
	Accretion expense		11		11
Balance at end of year		$	174	$	158