XML 34 R15.htm IDEA: XBRL DOCUMENT v3.21.2
Asset Retirement Obligations
9 Months Ended
Sep. 30, 2021
Asset Retirement Obligation Disclosure [Abstract]  
Asset Retirement Obligation
Note 9 Asset Retirement Obligations
Asset retirement obligations are included in Other deferred liabilities and credits in the Consolidated Balance Sheet.
During the three months ended September 30, 2021, UScellular performed a review of the assumptions and estimated future costs related to asset retirement obligations. The results of the review and other changes in asset retirement obligations during the nine months ended September 30, 2021 were as follows:
Asset Retirement Obligations
(Dollars in millions)
Balance at December 31, 2020$249 
Additional liabilities accrued
Revisions in estimated cash outflows43 
Disposition of assets(1)
Accretion expense11 
Balance at September 30, 2021$310