Revenue Recognition, Consolidated Balance Sheet (Details) - USD ($) $ in Millions		Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
Accounts receivable
Customers and agents, less allowances		$ 789	$ 775
Roaming		15	26
Prepaid expenses		66	79
Other current assets		32	21
Total current assets		1,591	1,483
Licenses		2,231	2,223
Investments in unconsolidated entities		450	415
Other assets and deferred charges		537	390
Total assets	[1]	7,048	6,841
Customer deposits and deferred revenues		132	185
Accrued taxes		58	56
Other current liabilities		90	90
Total current liabilities		616	733
Deferred income tax liability, net		526	461
Other deferred liabilities and credits		359	337
Retained earnings		2,375	2,157
Total U.S. Cellular shareholders' equity		3,907	3,677
Noncontrolling interests		11	10
Total equity		3,918	3,687	$ 3,682	$ 3,645
Total liabilities and equity	[1]	7,048	$ 6,841
Results under prior accounting standards
Accounts receivable
Customers and agents, less allowances		730
Roaming		26
Prepaid expenses		87
Other current assets		19
Total current assets		1,550
Licenses		2,230
Investments in unconsolidated entities		436
Other assets and deferred charges		383
Total assets		6,838
Customer deposits and deferred revenues		158
Accrued taxes		59
Other current liabilities		86
Total current liabilities		638
Deferred income tax liability, net		477
Other deferred liabilities and credits		349
Retained earnings		2,203
Total U.S. Cellular shareholders' equity		3,735
Noncontrolling interests		10
Total equity		3,745
Total liabilities and equity		6,838
Adjustment
Accounts receivable
Customers and agents, less allowances		59
Roaming		(11)
Prepaid expenses		(21)
Other current assets		13
Total current assets		41
Licenses		1
Investments in unconsolidated entities		14
Other assets and deferred charges		154
Total assets		210
Customer deposits and deferred revenues		(26)
Accrued taxes		(1)
Other current liabilities		4
Total current liabilities		(22)
Deferred income tax liability, net		49
Other deferred liabilities and credits		10
Retained earnings		172
Total U.S. Cellular shareholders' equity		172
Noncontrolling interests		1
Total equity		173
Total liabilities and equity		$ 210

[1] The consolidated total assets as of March 31, 2018 and December 31, 2017, include assets held by consolidated variable interest entities (VIEs) of $793 million and $785 million, respectively, which are not available to be used to settle the obligations of U.S. Cellular. The consolidated total liabilities as of March 31, 2018 and December 31, 2017, include certain liabilities of consolidated VIEs of $21 million and $24 million, respectively, for which the creditors of the VIEs have no recourse to the general credit of U.S. Cellular. See Note 9 — Variable Interest Entities for additional information.