United States Cellular (USM) 10-K 25 Feb 20 2019 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2019	Jan. 31, 2020	Jun. 28, 2019
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2019
Document Transition Report	false
Entity File Number	001-09712
Entity Registrant Name	UNITED STATES CELLULAR CORPORATION
Entity Central Index Key	0000821130
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	62-1147325
Entity Address, Address Line One	8410 West Bryn Mawr
Entity Address, City or Town	Chicago
Entity Address, State or Province	IL
Entity Address, Postal Zip Code	60631
City Area Code	(773)
Local Phone Number	399-8900
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 703,000,000
Share Price			$ 44.67
Common Shares
Title of 12(b) Security	Common Shares, $1 par value
Trading Symbol	USM
Security Exchange Name	NYSE
Entity Common Stock, Shares Outstanding		53,142,600
6.95% Senior Notes
Title of 12(b) Security	6.95% Senior Notes Due 2060
Trading Symbol	UZA
Security Exchange Name	NYSE
7.25% 2063 Senior Notes
Title of 12(b) Security	7.25% Senior Notes Due 2063
Trading Symbol	UZB
Security Exchange Name	NYSE
7.25% 2064 Senior Notes
Title of 12(b) Security	7.25% Senior Notes Due 2064
Trading Symbol	UZC
Security Exchange Name	NYSE
Series A Common Shares
Entity Common Stock, Shares Outstanding		33,005,900

Consolidated Statement Of Opera

Consolidated Statement Of Operations - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating revenues
Total operating revenues	$ 4,022	$ 3,967	$ 3,890
Operating expenses
Selling, general and administrative (including charges from affiliates of $82 million, $86 million and $85 million in 2019, 2018 and 2017)	1,406	1,388	1,412
Depreciation, amortization and accretion	702	640	615
Loss on impairment of goodwill	0	0	370
(Gain) loss on asset disposals, net	19	10	17
(Gain) loss on sale of business and other exit costs, net	(1)	0	(1)
(Gain) loss on license sales and exchanges, net	0	(18)	(22)
Total operating expenses	3,910	3,809	4,194
Operating income (loss)	112	158	(304)
Investment and other income (expense)
Equity in earnings of unconsolidated entities	166	159	137
Interest and dividend income	17	15	8
Interest expense	(110)	(116)	(113)
Other, net	0	(1)	0
Total investment and other income	73	57	32
Income (loss) before income taxes	185	215	(272)
Income tax expense (benefit)	52	51	(287)
Net income	133	164	15
Less: Net income attributable to noncontrolling interests, net of tax	6	14	3
Net income attributable to U.S. Cellular shareholders	$ 127	$ 150	$ 12
Basic weighted average shares outstanding (in shares)	86	86	85
Basic earnings per share attributable to U.S. Cellular shareholders (in dollars per share)	$ 1.47	$ 1.75	$ 0.14
Diluted weighted average shares outstanding (in shares)	88	87	86
Diluted earnings per share attributable to U.S. Cellular shareholders (in dollars per share)	$ 1.44	$ 1.72	$ 0.14
Service
Operating revenues
Total operating revenues	$ 3,035	$ 2,978	$ 2,978
Operating expenses
Cost of goods and services sold	756	758	732
Equipment sales
Operating revenues
Total operating revenues	987	989	912
Operating expenses
Cost of goods and services sold	$ 1,028	$ 1,031	$ 1,071

Consolidated Statement Of Ope_2

Consolidated Statement Of Operations (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating expenses
Selling, general and administrative, charges from affiliates	$ 82	$ 86	$ 85

Consolidated Statement of Cash

Consolidated Statement of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities
Net income	$ 133	$ 164	$ 15
Add (deduct) adjustments to reconcile net income to net cash flows from operating activities
Depreciation, amortization and accretion	702	640	615
Bad debts expense	107	95	89
Stock-based compensation expense	41	37	30
Deferred income taxes, net	(4)	(3)	(365)
Equity in earnings of unconsolidated entities	(166)	(159)	(137)
Distributions from unconsolidated entities	161	152	136
Loss on impairment of goodwill	0	0	370
(Gain) loss on asset disposals, net	19	10	17
(Gain) loss on sale of business and other exit costs, net	(1)	0	(1)
(Gain) loss on license sales and exchanges, net	0	(18)	(22)
Other operating activities	4	3	2
Changes in assets and liabilities from operations
Accounts receivable	(46)	(39)	(68)
Equipment installment plans receivable	(97)	(149)	(261)
Inventory	(20)	(4)	0
Accounts payable	(69)	3	(14)
Customer deposits and deferred revenues	(8)	7	(3)
Accrued taxes	(23)	(39)	26
Other assets and liabilities	(9)	9	40
Net cash provided by operating activities	724	709	469
Cash flows from investing activities
Cash paid for additions to property, plant and equipment	(650)	(512)	(465)
Cash paid for licenses	(266)	(8)	(189)
Cash received from investments	29	50	0
Cash paid for investments	(11)	(17)	(50)
Cash received from divestitures and exchanges	41	24	21
Other investing activities	(7)	(1)	0
Net cash used in investing activities	(864)	(464)	(683)
Cash flows from financing activities
Repayment of long-term debt	(116)	(19)	(14)
Common shares reissued for benefit plans, net of tax payments	(9)	18	1
Repurchase of Common Shares	(21)	0	0
Distributions to noncontrolling interests	(4)	(6)	(4)
Other financing activities	(2)	(7)	(3)
Net cash used in financing activities	(152)	(14)	(20)
Net increase (decrease) in cash, cash equivalents and restricted cash	(292)	231	(234)
Cash, cash equivalents and restricted cash
Beginning of period	583	352	586
End of period	$ 291	$ 583	$ 352

Consolidated Balance Sheet

Consolidated Balance Sheet - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Current assets
Cash and cash equivalents	$ 285	$ 580
Short-term investments	0	17
Accounts receivable
Customers and agents, less allowances of $70 and $66, respectively	919	908
Roaming	27	20
Affiliated	1	2
Other, less allowances of $1 and $2, respectively	63	46
Inventory, net	162	142
Prepaid expenses	50	63
Income taxes receivable	46	15
Other current assets	20	19
Total current assets	1,573	1,812
Assets held for sale	0	54
Licenses	2,471	2,186
Investments in unconsolidated entities	447	441
Property, plant and equipment
In service and under construction	8,293	7,778
Less: Accumulated depreciation and amortization	6,086	5,576
Property, plant and equipment, net	2,207	2,202
Operating lease right-of-use assets	900	0
Other assets and deferred charges	566	579
Total assets	8,164	7,274
Current liabilities
Current portion of long-term debt	8	19
Accounts payable
Affiliated	8	9
Trade	296	304
Customer deposits and deferred revenues	148	157
Accrued taxes	30	30
Accrued compensation	76	78
Short-term operating lease liabilities	105	0
Other current liabilities	79	94
Total current liabilities	750	691
Liabilities held for sale	0	1
Deferred liabilities and credits
Deferred income tax liability, net	507	510
Long-term operating lease liabilities	865	0
Other deferred liabilities and credits	319	389
Long-term debt, net	1,502	1,605
Commitments and contingencies
Noncontrolling interests with redemption features	11	11
U.S. Cellular shareholders’ equity
Series A Common and Common Shares Authorized 190 shares (50 Series A Common and 140 Common Shares) Issued 88 shares (33 Series A Common and 55 Common Shares) Outstanding 86 shares (33 Series A Common and 53 Common Shares) Par Value ($1.00 per share) ($33 Series A Common and $55 Common Shares)	88	88
Additional paid-in capital	1,629	1,590
Treasury shares, at cost, 2 Common Shares	(70)	(65)
Retained earnings	2,550	2,444
Total U.S. Cellular shareholders' equity	4,197	4,057
Noncontrolling interests	13	10
Total equity	4,210	4,067
Total liabilities and equity	$ 8,164	$ 7,274

Consolidated Balance Sheet (Par

Consolidated Balance Sheet (Parenthetical) - USD ($) shares in Millions, $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Accounts receivable
Customers and agents allowances	$ 70	$ 66
Other allowances	$ 1	$ 2
U.S. Cellular shareholders’ equity
Authorized shares (in shares)	190	190
Issued shares (in shares)	88	88
Outstanding shares (in shares)	86	86
Par value	$ 88	$ 88
Variable Interest Entities VIE's
Total VIE assets that can be used to settle only the VIEs' obligations	930	868
Total VIE liabilities for which creditors have no recourse	$ 22	$ 23
Series A Common Shares
U.S. Cellular shareholders’ equity
Authorized shares (in shares)	50	50
Issued shares (in shares)	33	33
Outstanding shares (in shares)	33	33
Par value per share (in dollars per share)	$ 1	$ 1
Par value	$ 33	$ 33
Common Shares
U.S. Cellular shareholders’ equity
Authorized shares (in shares)	140	140
Issued shares (in shares)	55	55
Outstanding shares (in shares)	53	53
Par value per share (in dollars per share)	$ 1	$ 1
Par value	$ 55	$ 55
Treasury shares (in shares)	2	2

Consolidated Statement of Chang

Consolidated Statement of Changes in Equity - USD ($) $ in Millions	Total	Series A Common and Common shares	Additional paid-in capital	Treasury shares	Retained earnings	Total U.S. Cellular shareholders' equity	Noncontrolling interests
Beginning balance at Dec. 31, 2016	$ 3,645	$ 88	$ 1,522	$ (136)	$ 2,160	$ 3,634	$ 11
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to U.S. Cellular shareholders	12				12	12
Net income attributable to noncontrolling interests classified as equity	3					0	3
Incentive and compensation plans	1			16	(15)	1
Stock-based compensation awards	30		30			30
Distributions to noncontrolling interests	(4)					0	(4)
Ending balance at Dec. 31, 2017	3,687	88	1,552	(120)	2,157	3,677	10
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of accounting change	176				175	175	1
Net income attributable to U.S. Cellular shareholders	150				150	150
Net income attributable to noncontrolling interests classified as equity	2					0	2
Incentive and compensation plans	18		1	55	(38)	18
Stock-based compensation awards	37		37			37
Distributions to noncontrolling interests	(3)					0	(3)
Ending balance at Dec. 31, 2018	4,067	88	1,590	(65)	2,444	4,057	10
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of accounting change	2				2	2
Net income attributable to U.S. Cellular shareholders	127				127	127
Net income attributable to noncontrolling interests classified as equity	6					0	6
Repurchase of Common Shares	(21)			(21)		(21)
Incentive and compensation plans	(9)		(2)	16	(23)	(9)
Stock-based compensation awards	41		41			41
Distributions to noncontrolling interests	(3)					0	(3)
Ending balance at Dec. 31, 2019	$ 4,210	$ 88	$ 1,629	$ (70)	$ 2,550	$ 4,197	$ 13

Summary of Significant Accounti

Summary of Significant Accounting Policies and Recent Accounting Pronouncements	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Summary of Significant Accounting Policies and Recent Accounting Pronouncements	Note 1 Summary of Significant Accounting Policies and Recent Accounting Pronouncements United States Cellular Corporation (U.S. Cellular), a Delaware Corporation, is an 82% -owned subsidiary of Telephone and Data Systems, Inc. (TDS). Nature of Operations U.S. Cellular owns, operates and invests in wireless systems throughout the United States. As of December 31, 2019 , U.S. Cellular served customers with 4.9 million total connections. U.S. Cellular has one reportable segment. Principles of Consolidation The accounting policies of U.S. Cellular conform to accounting principles generally accepted in the United States of America (GAAP) as set forth in the Financial Accounting Standards Board (FASB) Accounting Standards Codification (ASC). Unless otherwise specified, references to accounting provisions and GAAP in these notes refer to the requirements of the FASB ASC. The consolidated financial statements include the accounts of U.S. Cellular, subsidiaries in which it has a controlling financial interest, general partnerships in which U.S. Cellular has a majority partnership interest and certain entities in which U.S. Cellular has a variable interest that requires consolidation under GAAP. See Note 14 — Variable Interest Entities for additional information relating to U.S. Cellular’s VIEs. All material intercompany accounts and transactions have been eliminated. Use of Estimates The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect (a) the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and (b) the reported amounts of revenues and expenses during the reported period. Actual results could differ from those estimates. Significant estimates are involved in accounting for indefinite-lived intangible assets and income taxes. Cash, Cash Equivalents and Restricted Cash Cash and cash equivalents include cash and highly liquid investments with original maturities of three months or less. Cash and cash equivalents subject to contractual restrictions are classified as restricted cash. The following table provides a reconciliation of Cash and cash equivalents and restricted cash reported in the Consolidated Balance Sheet to the total of the amounts in the Consolidated Statement of Cash Flows. December 31, 2019 2018 (Dollars in millions) Cash and cash equivalents $ 285 $ 580 Restricted cash included in Other current assets 6 3 Cash, cash equivalents and restricted cash in the statement of cash flows $ 291 $ 583 Accounts Receivable and Allowance for Doubtful Accounts Accounts receivable consist primarily of amounts owed by customers for wireless services and equipment sales, including sales of certain devices and accessories under installment plans, by agents for sales of equipment to them and by other wireless carriers whose customers have used U.S. Cellular’s wireless systems. The allowance for doubtful accounts is the best estimate of the amount of probable credit losses related to existing billed and unbilled accounts receivable. The allowance is estimated based on historical experience, account aging and other factors that could affect collectability. Accounts receivable balances are reviewed on either an aggregate or individual basis for collectability depending on the type of receivable. When it is probable that an account balance will not be collected, the account balance is charged against the allowance for doubtful accounts. U.S. Cellular does not have any off-balance sheet credit exposure related to its customers. Inventory Inventory consists primarily of wireless devices stated at the lower of cost, which approximates cost determined on the first-in first-out basis, or net realizable value. Net realizable value is determined by reference to the stand-alone selling price. Licenses Licenses consist of direct and incremental costs incurred in acquiring Federal Communications Commission (FCC) wireless spectrum licenses that provide U.S. Cellular with the exclusive right to utilize designated radio spectrum within specific geographic service areas to provide wireless service. Although wireless spectrum licenses are issued for a fixed period of time, generally ten years , or in some cases twelve or fifteen years , the FCC has granted license renewals routinely and at a nominal cost. The wireless spectrum licenses held by U.S. Cellular expire at various dates. U.S. Cellular believes that it is probable that its future wireless spectrum license renewal applications will be granted. U.S. Cellular determined that there are currently no legal, regulatory, contractual, competitive, economic or other factors that limit the useful lives of the wireless spectrum licenses. Therefore, U.S. Cellular has determined that wireless spectrum licenses are indefinite-lived intangible assets. U.S. Cellular performs its annual impairment assessment of wireless spectrum licenses as of November 1 of each year or more frequently if there are events or circumstances that cause U.S. Cellular to believe it is more likely than not that the carrying value of wireless spectrum licenses exceeds fair value. For purposes of its impairment testing, U.S. Cellular separated its FCC wireless spectrum licenses into eight units of accounting. The eight units of accounting consisted of one unit of accounting for developed operating market wireless spectrum licenses (built wireless spectrum licenses) and seven geographic non-operating market wireless spectrum licenses (unbuilt wireless spectrum licenses). U.S. Cellular performed a quantitative impairment assessment in 2019 and a qualitative impairment assessment in 2018 to determine whether the wireless spectrum licenses were impaired. Based on the impairment assessments performed, U.S. Cellular did no t have an impairment of its wireless spectrum licenses in 2019 or 2018 . See Note 7 — Intangible Assets for additional details related to wireless spectrum licenses. Investments in Unconsolidated Entities For its equity method investments for which financial information is readily available, U.S. Cellular records its equity in the earnings of the entity in the current period. For its equity method investments for which financial information is not readily available, U.S. Cellular records its equity in the earnings of the entity on a one quarter lag basis. Property, Plant and Equipment U.S. Cellular’s Property, plant and equipment is stated at the original cost of construction or purchase including capitalized costs of certain taxes, payroll-related expenses, interest and estimated costs to remove the assets. Expenditures that enhance the productive capacity of assets in service or extend their useful lives are capitalized and depreciated. Expenditures for maintenance and repairs of assets in service are charged to System operations expense or Selling, general and administrative expense, as applicable. Retirements and disposals of assets are recorded by removing the original cost of the asset (along with the related accumulated depreciation) from plant in service and recording it, together with proceeds, if any, and net removal costs (removal costs less an applicable accrued asset retirement obligation and salvage value realized), as a gain or loss, as appropriate. U.S. Cellular capitalizes certain costs of developing new information systems. Software licenses that qualify for capitalization as an asset are accounted for as the acquisition of an intangible asset and the incurrence of a liability to the extent that the license fees are not fully paid at acquisition. Depreciation and Amortization Depreciation is provided using the straight-line method over the estimated useful life of the related asset. U.S. Cellular depreciates leasehold improvement assets over periods ranging from one year to thirty years ; such periods approximate the shorter of the assets’ economic lives or the specific lease terms. Useful lives of specific assets are reviewed throughout the year to determine if changes in technology or other business changes would warrant accelerating the depreciation of those specific assets. There were no material changes to the assigned useful lives of the various categories of property, plant and equipment in 2019 , 2018 or 2017 . However, depreciation for certain specific assets was accelerated due to changes in technology. See Note 9 — Property, Plant and Equipment for additional details related to useful lives. Impairment of Long-Lived Assets U.S. Cellular reviews long-lived assets for impairment whenever events or changes in circumstances indicate that the assets might be impaired. U.S. Cellular has one asset group for purposes of assessing property, plant and equipment for impairment based on the integrated nature of its assets and operations. The cash flows generated by this single interdependent asset group represent the lowest level for which identifiable cash flows are largely independent of the cash flows of other groups of assets and liabilities. Leases A lease is generally present in a contract if the lessee controls the use of identified property, plant or equipment for a period of time in exchange for consideration. See Note 10 — Leases for additional details related to leases. Agent Liabilities U.S. Cellular has relationships with agents, which are independent businesses that obtain customers for U.S. Cellular. At December 31, 2019 and 2018 , U.S. Cellular had accrued $59 million and $63 million , respectively, in agent related liabilities. These amounts are included in Other current liabilities in the Consolidated Balance Sheet. Debt Issuance Costs Debt issuance costs include underwriters’ and legal fees and other charges related to issuing and renewing various borrowing instruments and other long–term agreements, and are amortized over the respective term of each instrument. Debt issuance costs related to U.S. Cellular’s revolving credit agreement and receivables securitization agreement are recorded in Other assets and deferred charges in the Consolidated Balance Sheet. All other debt issuance costs are presented as an offset to the related debt obligation in the Consolidated Balance Sheet. Asset Retirement Obligations U.S. Cellular records asset retirement obligations for the fair value of legal obligations associated with asset retirements and a corresponding increase in the carrying amount of the related long-lived asset in the period in which the obligations are incurred. In periods subsequent to initial measurement, U.S. Cellular recognizes changes in the liability resulting from the passage of time and updates to the timing or the amount of the original estimates. The liability is accreted to its estimated settlement date value over the period to the estimated settlement date. The change in the carrying amount of the long-lived asset is depreciated over the average remaining life of the related asset. See Note 11 — Asset Retirement Obligations for additional information. Treasury Shares Common Shares repurchased by U.S. Cellular are recorded at cost as treasury shares and result in a reduction of equity. When treasury shares are reissued, U.S. Cellular determines the cost using the first-in, first-out cost method. The difference between the cost of the treasury shares and reissuance price is included in Additional paid-in capital or Retained earnings. Revenue Recognition Revenues from sales of equipment and products are recognized when control has transferred to the customer, agent or third-party distributor. Service revenues are recognized as the related service is provided. See Note 2 — Revenue Recognition for additional information on U.S. Cellular's policies related to Revenues. Advertising Costs U.S. Cellular expenses advertising costs as incurred. Advertising costs totaled $212 million , $215 million and $211 million in 2019 , 2018 and 2017 , respectively. Income Taxes U.S. Cellular is included in a consolidated federal income tax return with other members of the TDS consolidated group. For financial statement purposes, U.S. Cellular and its subsidiaries calculate their income, income taxes and credits as if they comprised a separate affiliated group. Under a tax allocation agreement between TDS and U.S. Cellular, U.S. Cellular remits its applicable income tax payments to TDS. U.S. Cellular had a tax receivable balance with TDS of $46 million and $14 million as of December 31, 2019 , and 2018 , respectively. Deferred taxes are computed using the liability method, whereby deferred tax assets are recognized for future deductible temporary differences and operating loss carryforwards, and deferred tax liabilities are recognized for future taxable temporary differences. Both deferred tax assets and liabilities are measured using the enacted tax rates in effect when the temporary differences are expected to reverse. Temporary differences are the differences between the reported amounts of assets and liabilities and their tax bases. Deferred tax assets and liabilities are adjusted for the effects of changes in tax laws and rates on the date of enactment. Deferred tax assets are reduced by a valuation allowance when it is more likely than not that some portion or all of the deferred tax assets will not be realized. U.S. Cellular evaluates income tax uncertainties, assesses the probability of the ultimate settlement with the applicable taxing authority and records an amount based on that assessment. Deferred taxes are reported as a net non-current asset or liability by jurisdiction. Any corresponding valuation allowance to reduce the amount of deferred tax assets is also recorded as non-current. See Note 5 — Income Taxes for additional information. Stock-Based Compensation and Other Plans U.S. Cellular has established a long-term incentive plan and a non-employee director compensation plan. These plans are considered compensatory plans and, therefore, recognition of costs for grants made under these plans is required. U.S. Cellular recognizes stock compensation expense based upon the fair value of the specific awards granted using established valuation methodologies. The amount of stock compensation cost recognized on either a straight-line basis or graded attribution method is based on the portion of the award that is expected to vest over the requisite service period, which generally represents the vesting period. Stock-based compensation cost recognized has been reduced for estimated forfeitures. Forfeitures are estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates. See Note 17 — Stock-Based Compensation for additional information. Defined Contribution Plans U.S. Cellular participates in a qualified noncontributory defined contribution pension plan sponsored by TDS; such plan provides pension benefits for the employees of U.S. Cellular and its subsidiaries. Under this plan, pension benefits and costs are calculated separately for each participant and are funded currently. Pension costs were $11 million in 2019 , 2018 and 2017 . U.S. Cellular also participates in a defined contribution retirement savings plan (401(k) plan) sponsored by TDS. Total costs incurred for U.S. Cellular’s contributions to the 401(k) plan were $14 million , $15 million and $16 million in 2019 , 2018 and 2017 , respectively. Recently Issued Accounting Pronouncements In June 2016, the FASB issued Accounting Standards Update 2016-13, Financial Instruments - Credit Losses: Measurement of Credit Losses on Financial Instruments (ASU 2016-13). ASU 2016-13 requires entities to use a new forward-looking, expected loss model to estimate credit losses. It also requires additional disclosure relating to the credit quality of trade and other receivables, including information relating to management’s estimate of credit allowances. U.S. Cellular is required to adopt ASU 2016-13 on January 1, 2020, using the modified retrospective approach. The adoption of ASU 2016-13 is not expected to have a significant impact on U.S. Cellular's financial position or results of operations. In August 2018, the FASB issued Accounting Standards Update 2018-15, Intangibles - Goodwill and Other - Internal-Use Software: Customer's Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract (ASU 2018-15). ASU 2018-15 aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the existing guidance for capitalizing implementation costs for an arrangement that has a software license. The service element of a hosting arrangement will continue to be expensed as incurred. Any capitalized implementation costs will be amortized over the period of the service contract. U.S. Cellular is required to adopt ASU 2018-15 on January 1, 2020, either retrospectively or prospectively to eligible costs incurred on or after the date that this guidance is first applied. The adoption of ASU 2018-15 is not expected to have a significant impact on U.S. Cellular's financial position or results of operations.

Revenue Recognition

Revenue Recognition	12 Months Ended
	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Revenue Recognition	Note 2 Revenue Recognition Change in Accounting Policy In May 2014, the FASB issued Accounting Standards Update 2014-09, Revenue from Contracts with Customers and subsequently amended the standard with several Accounting Standards Updates, collectively referred to as ASC 606. U.S. Cellular adopted and applied the provisions of ASC 606 as of January 1, 2018, using a modified retrospective method. Under this method, the new accounting standard is applied only to the most recent period presented, recognizing the cumulative effect of the accounting change as an adjustment to the beginning balance of retained earnings. Accordingly, prior periods have not been recast to reflect the new accounting standard. The cumulative effect of applying the provisions of ASC 606 was an increase of $175 million to retained earnings as of January 1, 2018. As a practical expedient, U.S. Cellular groups similar contracts or similar performance obligations together into portfolios of contracts or performance obligations if doing so does not result in a significant difference from accounting for the individual contracts discretely. U.S. Cellular applies this grouping method for the following types of transactions: device activation fees, contract acquisition costs, and certain customer promotions. Contract portfolios are recognized over the respective expected customer lives or terms of the contracts. Nature of goods and services The following is a description of principal activities from which U.S. Cellular generates its revenues. Services and products Nature, timing of satisfaction of performance obligations, and significant payment terms Wireless services Wireless service includes voice, messaging and data services. Revenue is recognized in Service revenues as wireless service is provided to the customer. Wireless services generally are billed and paid in advance on a monthly basis. Wireless devices and accessories U.S. Cellular offers a comprehensive range of wireless devices such as handsets, tablets, mobile hotspots, home phones and routers for use by its customers, as well as accessories. U.S. Cellular also sells wireless devices to agents and other third-party distributors for resale. U.S. Cellular frequently discounts wireless devices sold to new and current customers. U.S. Cellular also offers customers the option to purchase certain devices and accessories under installment contracts over a specified time period. For certain equipment installment plans, after a specified period of time, the customer may have the right to upgrade to a new device. Such upgrades require the customer to enter into an equipment installment contract for the new device, and transfer the existing device to U.S. Cellular. U.S. Cellular recognizes revenue in Equipment sales revenues when control of the device or accessory is transferred to the customer, agent or third-party distributor, which is generally upon delivery. Wireless roaming U.S. Cellular receives roaming revenues when other wireless carriers’ customers use U.S. Cellular’s wireless systems. U.S. Cellular recognizes revenue in Service revenues when the roaming service is provided. Wireless Eligible Telecommunications Carrier (ETC) Revenues Telecommunications companies may be designated by states, or in some cases by the FCC, as an ETC to receive support payments from the Universal Service Fund if they provide specified services in “high cost” areas. ETC revenues recognized in the reporting period represent the amounts which U.S. Cellular is entitled to receive for such period, as determined and approved in connection with U.S. Cellular’s designation as an ETC in various states. Wireless tower rents U.S. Cellular receives tower rental revenues when another carrier leases tower space on a U.S. Cellular owned tower. U.S. Cellular recognizes revenue in Service revenues in the period during which the services are provided. Significant Judgments Revenues from sales of equipment are recognized when control has transferred to the customer, agent or third-party distributor. Service revenues are recognized as the related service is provided. Services are deemed to be highly interrelated when the method and timing of transfer and performance risk are the same. Highly interrelated services that are determined to not be distinct have been grouped into a single performance obligation. Each month of services promised is a performance obligation. The series of monthly service performance obligations promised over the course of the contract are combined into a single performance obligation for purposes of the allocation. U.S. Cellular has made judgments regarding transaction price, including but not limited to issues relating to variable consideration, time value of money and returns. When determined to be significant in the context of the contract, these items are considered in the valuation of transaction price at contract inception or modification, as appropriate. Multiple Performance Obligations U.S. Cellular sells bundled service and equipment offerings. In these instances, U.S. Cellular recognizes its revenue based on the relative standalone selling prices for each distinct service or equipment performance obligation, or bundles thereof. U.S. Cellular estimates the standalone selling price of the device or accessory to be its retail price excluding discounts. U.S. Cellular estimates the standalone selling price of wireless service to be the price offered to customers on month-to-month contracts. Equipment Installment Plans Equipment revenue under equipment installment plan contracts is recognized at the time the device is delivered to the customer for the amount allocated to the equipment. Incentives Discounts, incentives, and rebates to agents and end customers that are deemed cash are recognized as a reduction of Operating revenues concurrently with the associated revenue. From time to time, U.S. Cellular may offer certain promotions to incentivize customers to switch to, or to purchase additional services from, U.S. Cellular. Under these types of promotions, an eligible customer may receive an incentive in the form of a discount off additional services purchased shown as a credit to the customer’s monthly bill. U.S. Cellular accounts for the future discounts as material rights at the time of the initial transaction by allocating and deferring revenue based on the relative proportion of the future discounts in comparison to the aggregate initial purchase. The deferred revenue will be recognized as service revenue in future periods. Amounts Collected from Customers and Remitted to Governmental Authorities U.S. Cellular records amounts collected from customers and remitted to governmental authorities on a net basis within a liability account if the amount is assessed upon the customer and U.S. Cellular merely acts as an agent in collecting the amount on behalf of the imposing governmental authority. If the amount is assessed upon U.S. Cellular, then amounts collected from customers are recorded in Service revenues and amounts remitted to governmental authorities are recorded in Selling, general and administrative expenses in the Consolidated Statement of Operations. The amounts recorded gross in revenues that are billed to customers and remitted to governmental authorities totaled $53 million , $67 million and $58 million for 2019 , 2018 and 2017 , respectively. Disaggregation of Revenue In the following table, U.S. Cellular's revenues are disaggregated by type of service, which represents the relevant categorization of revenues for U.S. Cellular, and timing of recognition. Service revenues are recognized over time and Equipment sales are point in time. Year Ended Year Ended December 31, 2018 (Dollars in millions) Revenues from contracts with customers: Retail service $ 2,650 $ 2,623 Inbound roaming 174 154 Other service 137 135 Service revenues from contracts with customers 2,961 2,912 Equipment sales 987 989 Total revenues from contracts with customers 1 $ 3,948 $ 3,901 1 Revenue line items in this table will not agree to amounts presented in the Consolidated Statement of Operations as the amounts in this table only include revenue resulting from contracts with customers. Contract Balances For contracts that involve multiple element service and equipment offerings, the transaction price is allocated to each performance obligation based on its relative standalone selling price. When payment is collected in advance of delivery of goods or services, a contract liability is recorded. A contract asset is recorded when revenue is recognized in advance of U.S. Cellular’s right to receive consideration. Once there is an unconditional right to receive the consideration, U.S. Cellular bills the customer under the terms of the respective contract and the amounts are recorded as receivables. U.S. Cellular recognizes Equipment sales revenue when the equipment is delivered to the customer and a corresponding contract asset or liability is recorded for the difference between the amount of revenue recognized and the amount billed to the customer in cases where discounts are offered. The contract asset or liability is reduced over the contract term as service is provided and billed to the customer. The following table provides balances for contract assets from contracts with customers, which are recorded in Other current assets and Other assets and deferred charges in the Consolidated Balance Sheet, and contract liabilities from contracts with customers, which are recorded in Customer deposits and deferred revenues and Other deferred liabilities and credits in the Consolidated Balance Sheet. December 31, 2019 December 31, 2018 (Dollars in millions) Contract assets $ 7 $ 9 Contract liabilities 1 $ 154 $ 147 1 The contract liability balance at December 31, 2018 differs from the amount reported in Note 2 — Revenue Recognition of the 2018 Form 10-K, as the previously reported amount included certain lease-related balances that did not result from contracts with customers. Revenue recognized related to contract liabilities existing at January 1, 2019 was $128 million for the year ended December 31, 2019 . Transaction price allocated to the remaining performance obligations The following table includes estimated service revenues expected to be recognized related to performance obligations that are unsatisfied (or partially unsatisfied) at the end of the reporting period. These estimates represent service revenues to be recognized when wireless services are delivered to customers pursuant to service plan contracts and under certain roaming agreements with other carriers. These estimates are based on contracts in place as of December 31, 2019 , and may vary from actual results. As practical expedients, revenue related to contracts of less than one year, generally month-to-month contracts, and contracts with a fixed per-unit price and variable quantity, are excluded from these estimates. Service Revenues (Dollars in millions) 2020 $ 206 2021 90 Thereafter 160 Total $ 456 Contract Cost Assets U.S. Cellular expects that commission fees paid as a result of obtaining contracts are recoverable and therefore U.S. Cellular capitalizes these costs. As a practical expedient, costs with an amortization period of one year or less are not capitalized. The contract cost asset balance related to commission fees was $133 million and $139 million at December 31, 2019 and 2018 , respectively and was recorded in Other assets and deferred charges in the Consolidated Balance Sheet. Capitalized commission fees are amortized based on the timing of transfer of the goods or services to which the assets relate, typically the contract term. Amortization of contract cost assets was $109 million and $108 million for the year ended December 31, 2019 and 2018

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurements	Note 3 Fair Value Measurements As of December 31, 2019 and 2018 , U.S. Cellular did not have any material financial or nonfinancial assets or liabilities that were required to be recorded at fair value in its Consolidated Balance Sheet in accordance with GAAP. The provisions of GAAP establish a fair value hierarchy that contains three levels for inputs used in fair value measurements. Level 1 inputs include quoted market prices for identical assets or liabilities in active markets. Level 2 inputs include quoted market prices for similar assets and liabilities in active markets or quoted market prices for identical assets and liabilities in inactive markets. Level 3 inputs are unobservable. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. A financial instrument’s level within the fair value hierarchy is not representative of its expected performance or its overall risk profile and, therefore, Level 3 assets are not necessarily higher risk than Level 2 assets or Level 1 assets. U.S. Cellular has applied the provisions of fair value accounting for purposes of computing the fair value of financial instruments for disclosure purposes as displayed below. Level within the Fair Value Hierarchy December 31, 2019 December 31, 2018 Book Value Fair Value Book Value Fair Value (Dollars in millions) Cash and cash equivalents 1 $ 285 $ 285 $ 580 $ 580 Short-term investments 1 — — 17 17 Long-term debt Retail 2 917 943 917 850 Institutional 2 534 594 534 531 Other 2 83 83 180 180 The fair values of Cash and cash equivalents and Short-term investments approximate their book values due to the short-term nature of these financial instruments. Long-term debt excludes lease obligations, other installment arrangements, the current portion of Long-term debt and debt financing costs. The fair value of “Retail” Long-term debt was estimated using market prices for the 7.25% 2063 Senior Notes, 7.25% 2064 Senior Notes and 6.95% Senior Notes. U.S. Cellular’s “Institutional” debt consists of the 6.7% Senior Notes which are traded over the counter. U.S. Cellular’s “Other” debt consists of a senior term loan credit agreement. U.S. Cellular estimated the fair value of its Institutional and Other debt through a discounted cash flow analysis using the interest rates or estimated yield to maturity for each borrowing, which ranged from 3.55% to 5.73% and 5.03% to 6.97% at December 31, 2019 and 2018 , respectively.

Equipment Installment Plans

Equipment Installment Plans	12 Months Ended
	Dec. 31, 2019
Receivables [Abstract]
Equipment Installment Plans	Note 4 Equipment Installment Plans U.S. Cellular sells devices to customers under equipment installment plans over a specified time period. For certain equipment installment plans, after a specified period of time or amount of payments, the customer may have the right to upgrade to a new device and have the remaining unpaid equipment installment contract balance waived, subject to certain conditions, including trading in the original device in good working condition and signing a new equipment installment contract. The following table summarizes equipment installment plan receivables as of December 31, 2019 and 2018 . December 31, 2019 2018 (Dollars in millions) Equipment installment plan receivables, gross $ 1,008 $ 974 Allowance for credit losses (84 ) (77 ) Equipment installment plan receivables, net $ 924 $ 897 Net balance presented in the Consolidated Balance Sheet as: Accounts receivable — Customers and agents (Current portion) $ 587 $ 560 Other assets and deferred charges (Non-current portion) 337 337 Equipment installment plan receivables, net $ 924 $ 897 U.S. Cellular uses various inputs, including internal data, information from credit bureaus and other sources, to evaluate the credit profiles of its customers. From this evaluation, a credit class is assigned to the customer that determines the number of eligible lines, the amount of credit available, and the down payment requirement, if any. Customers assigned to credit classes requiring no down payment represent a lower risk category, whereas those assigned to credit classes requiring a down payment represent a higher risk category. A customer's assigned credit class is reviewed periodically and a change is made, if appropriate. The balance and aging of the equipment installment plan receivables on a gross basis by current credit category were as follows: December 31, 2019 December 31, 2018 Lower Risk Higher Risk Total Lower Risk Higher Risk Total (Dollars in millions) Unbilled $ 931 $ 11 $ 942 $ 904 $ 17 $ 921 Billed — current 44 1 45 35 1 36 Billed — past due 20 1 21 15 2 17 Equipment installment plan receivables, gross $ 995 $ 13 $ 1,008 $ 954 $ 20 $ 974 The activity in the allowance for credit losses for equipment installment plan receivables was as follows: 2019 2018 (Dollars in millions) Allowance for credit losses, beginning of year $ 77 $ 65 Bad debts expense 82 71 Write-offs, net of recoveries (75 ) (59 ) Allowance for credit losses, end of year $ 84 $ 77

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Income Taxes	Note 5 Income Taxes U.S. Cellular is included in a consolidated federal income tax return and in certain state income tax returns with other members of the TDS consolidated group. For financial statement purposes, U.S. Cellular and its subsidiaries compute their income tax expense as if they comprised a separate affiliated group and were not included in the TDS consolidated group. U.S. Cellular’s current income taxes balances at December 31, 2019 and 2018 , were as follows: December 31, 2019 2018 (Dollars in millions) Federal income taxes receivable $ 44 $ 15 Net state income taxes receivable 2 — Income tax expense (benefit) is summarized as follows: Year Ended December 31, 2019 2018 2017 (Dollars in millions) Current Federal $ 44 $ 48 $ 68 State 12 6 10 Deferred Federal — (5 ) (354 ) State (4 ) 2 (11 ) Total income tax expense (benefit) $ 52 $ 51 $ (287 ) In December 2017, the Tax Act was signed into law. Following the guidance of FASB Accounting Standards Update 2018-05, Income Taxes: Amendments to SEC Paragraphs Pursuant to SEC Staff Accounting Bulletin No. 118 , Income tax expense (benefit) for the year ended December 31, 2017, included a provisional estimate for the impact of the Tax Act on U.S. Cellular's 2017 depreciation expense deduction. During 2018, U.S. Cellular completed a full analysis of depreciation expense deductions related to fixed assets placed in service during 2017 and Income tax expense (benefit) for 2018 included a benefit of $4 million related to this adjustment. A reconciliation of U.S. Cellular’s income tax expense computed at the statutory rate to the reported income tax expense, and the statutory federal income tax rate to U.S. Cellular’s effective income tax rate is as follows: Year Ended December 31, 2019 2018 2017 Amount Rate Amount Rate Amount Rate (Dollars in millions) Statutory federal income tax expense and rate $ 39 21.0 % $ 45 21.0 % $ (95 ) 35.0 % State income taxes, net of federal benefit 1 6 3.4 9 4.0 (4 ) 1.4 Effect of noncontrolling interests (1 ) (0.5 ) (1 ) (0.4 ) (2 ) 0.8 Federal income tax rate change 2 — — (4 ) (2.0 ) (254 ) 93.3 Change in federal valuation allowance 3 7 3.6 (1 ) (0.3 ) (5 ) 1.9 Goodwill impairment 4 — — — — 71 (26.2 ) Nondeductible compensation 2 1.3 4 1.8 4 (1.5 ) Tax credits (3 ) (1.5 ) — (0.1 ) — 0.1 Other differences, net 2 0.8 (1 ) (0.3 ) (2 ) 0.7 Total income tax expense (benefit) and rate $ 52 28.1 % $ 51 23.7 % $ (287 ) 105.5 % 1 State income taxes, net of federal benefit, include changes in unrecognized tax benefits as well as adjustments to the valuation allowance. 2 The Tax Act reduced the federal income tax rate from 35% to 21% for years after 2017. The $4 million tax benefit in 2018 relates primarily to finalizing the analysis for 2017 depreciation deductions as described above. The $254 million tax benefit in 2017 related to adjusting the deferred tax liability to the lower tax rate upon enactment of the Tax Act. 3 Change in federal valuation allowance in 2019 is due primarily to interest expense carryforwards not expected to be realized. The 2018 change also includes a change in judgment related to net operating loss carryforwards that are now realizable due to an internal restructuring. 4 Goodwill impairment reflects an adjustment to increase 2017 income tax expense by $71 million related to a portion of the impaired goodwill that is not amortizable for income tax purposes. See Note 7 — Intangible Assets for additional information related to the goodwill impairment. Significant components of U.S. Cellular’s deferred income tax assets and liabilities at December 31, 2019 and 2018 , were as follows 1 : December 31, 2019 2018 (Dollars in millions) Deferred tax assets Net operating loss (NOL) carryforwards $ 96 $ 96 Lease liabilities 230 — Asset retirement obligation 45 43 Other 84 114 Total deferred tax assets 455 253 Less valuation allowance (90 ) (75 ) Net deferred tax assets 365 178 Deferred tax liabilities Property, plant and equipment 284 299 Licenses/intangibles 230 207 Partnership investments 131 133 Lease assets 206 — Other 21 49 Total deferred tax liabilities 872 688 Net deferred income tax liability $ 507 $ 510 1 Certain prior year deferred tax assets and liabilities have been reclassified to align with the current year presentation. At December 31, 2019 , U.S. Cellular and certain subsidiaries had $1,895 million of state NOL carryforwards (generating a $86 million deferred tax asset) available to offset future taxable income. The state NOL carryforwards expire between 2020 and 2039 . Certain subsidiaries had federal NOL carryforwards (generating a $10 million deferred tax asset) available to offset their future taxable income. The federal NOL carryforwards generally expire between 2020 and 2037 , with the exception of federal NOLs generated after 2017, which do not expire. A valuation allowance was established for certain state NOL carryforwards and federal NOL carryforwards since it is more likely than not that a portion of such carryforwards will expire before they can be utilized. A summary of U.S. Cellular’s deferred tax asset valuation allowance is as follows: 2019 2018 2017 (Dollars in millions) Balance at beginning of year $ 75 $ 77 $ 65 Charged to income tax expense 15 5 12 Charged to Retained earnings — (7 ) — Balance at end of year $ 90 $ 75 $ 77 A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows: 2019 2018 2017 (Dollars in millions) Unrecognized tax benefits balance at beginning of year $ 48 $ 47 $ 43 Additions for tax positions of current year 7 6 6 Additions for tax positions of prior years — 1 1 Reductions for tax positions of prior years (6 ) — (1 ) Reductions for settlements of tax positions (1 ) — — Reductions for lapses in statutes of limitations — (6 ) (2 ) Unrecognized tax benefits balance at end of year $ 48 $ 48 $ 47 Unrecognized tax benefits are included in Accrued taxes and Other deferred liabilities and credits in the Consolidated Balance Sheet. If these benefits were recognized, they would have reduced income tax expense in 2019 , 2018 and 2017 by $37 million , $38 million and $38 million , respectively, net of the federal benefit from state income taxes. U.S. Cellular recognizes accrued interest and penalties related to unrecognized tax benefits in Income tax expense (benefit). The amounts charged to income tax expense related to interest and penalties resulted in an expense of $3 million in 2019 , a benefit of less than $1 million in 2018 and an expense of $3 million in 2017 . Net accrued liabilities for interest and penalties were $21 million and $19 million at December 31, 2019 and 2018 , respectively, and are included in Other deferred liabilities and credits in the Consolidated Balance Sheet. U.S. Cellular is included in TDS’ consolidated federal and certain state income tax returns. U.S. Cellular also files certain state and local income tax returns separately from TDS. With limited exceptions, TDS is no longer subject to federal and state income tax audits for the years prior to 2016 .

Earnings Per Share

Earnings Per Share	12 Months Ended
	Dec. 31, 2019
Earnings Per Share [Abstract]
Earnings Per Share	Note 6 Earnings Per Share Basic earnings per share attributable to U.S. Cellular shareholders is computed by dividing Net income attributable to U.S. Cellular shareholders by the weighted average number of Common Shares outstanding during the period. Diluted earnings per share attributable to U.S. Cellular shareholders is computed by dividing Net income attributable to U.S. Cellular shareholders by the weighted average number of Common Shares outstanding during the period adjusted to include the effects of potentially dilutive securities. Potentially dilutive securities primarily include incremental shares issuable upon the exercise of outstanding stock options and the vesting of performance and restricted stock units. The amounts used in computing basic and diluted earnings per share attributable to U.S. Cellular shareholders were as follows: Year Ended December 31, 2019 2018 2017 (Dollars and shares in millions, except per share amounts) Net income attributable to U.S. Cellular shareholders $ 127 $ 150 $ 12 Weighted average number of shares used in basic earnings per share 86 86 85 Effects of dilutive securities 2 1 1 Weighted average number of shares used in diluted earnings per share 88 87 86 Basic earnings per share attributable to U.S. Cellular shareholders $ 1.47 $ 1.75 $ 0.14 Diluted earnings per share attributable to U.S. Cellular shareholders $ 1.44 $ 1.72 $ 0.14 Certain Common Shares issuable upon the exercise of stock options or vesting of performance and restricted stock units were not included in weighted average diluted shares outstanding for the calculation of Diluted earnings per share attributable to U.S. Cellular shareholders because their effects were antidilutive. The number of such Common Shares excluded was less than 1 million shares, 2 million shares and 3 million shares for 2019 , 2018 and 2017 , respectively.

Intangible Assets

Intangible Assets	12 Months Ended
	Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets	Note 7 Intangible Assets Licenses U.S. Cellular reviews attractive opportunities to acquire additional wireless spectrum, including pursuant to FCC auctions. U.S. Cellular also may seek to divest outright or include in exchanges wireless spectrum that is not strategic to its long-term success. Activity related to U.S. Cellular's Licenses is presented below. 2019 2018 (Dollars in millions) Balance at beginning of year $ 2,186 $ 2,223 Acquisitions 267 8 Transferred to Assets held for sale — (51 ) Divestitures (10 ) (11 ) Exchanges - Licenses received 26 18 Exchanges - Licenses surrendered — (1 ) Capitalized interest 2 — Balance at end of year $ 2,471 $ 2,186 Auctions 101 and 102 In June 2019, the FCC announced by way of public notice that U.S. Cellular was the provisional winning bidder for 408 wireless spectrum licenses in its 28 GHz auction (Auction 101) and 282 wireless spectrum licenses in its 24 GHz auction (Auction 102) for an aggregate purchase price of $256 million . U.S. Cellular paid substantially all of the $256 million in the first half of 2019. The wireless spectrum licenses from Auction 101 were granted by the FCC on October 2, 2019, and the wireless spectrum licenses from Auction 102 were granted by the FCC on December 11, 2019. Goodwill — Interim Impairment Assessment in 2017 Based on 2017 developments, including wireless expansion plans announced by other companies and the results of the FCC’s forward auction of 600 MHz wireless spectrum licenses and other FCC actions, U.S. Cellular anticipated increased competition for customers in its primary operating markets from new and existing market participants over the long term. In addition, the widening adoption of unlimited data plans and other data pricing constructs across the industry, including U.S. Cellular’s introduction of unlimited plans in 2017, may limit the industry’s ability to monetize future growth in data usage. These factors when assessed and considered as part of U.S. Cellular’s annual planning process conducted in the third quarter of each year caused management to revise its long-range financial forecast in the third quarter of 2017. Based on the factors noted above, management identified a triggering event and performed a quantitative goodwill impairment test during the third quarter of 2017. The results of the interim goodwill impairment test indicated that the carrying value of the U.S. Cellular reporting unit exceeded its fair value. Therefore, U.S. Cellular recognized a loss on impairment of goodwill of $370 million to reduce the carrying value of goodwill to zero in the third quarter of 2017.

Investments in Unconsolidated E

Investments in Unconsolidated Entities	12 Months Ended
	Dec. 31, 2019
Equity Method Investments and Joint Ventures [Abstract]
Investments in Unconsolidated Entities	Note 8 Investments in Unconsolidated Entities Investments in unconsolidated entities consist of amounts invested in entities in which U.S. Cellular holds a noncontrolling interest. U.S. Cellular's Investments in unconsolidated entities are accounted for using either the equity method or measurement alternative method as shown in the table below. The carrying value of measurement alternative method investments represents cost minus any impairments plus or minus any observable price changes. December 31, 2019 2018 (Dollars in millions) Equity method investments: Capital contributions, loans, advances and adjustments $ 105 $ 105 Cumulative share of income 2,060 1,892 Cumulative share of distributions (1,725 ) (1,563 ) Total equity method investments 440 434 Measurement alternative method investments 7 7 Total investments in unconsolidated entities $ 447 $ 441 The following tables, which are based on information provided in part by third parties, summarize the combined assets, liabilities and equity, and results of operations of U.S. Cellular’s equity method investments: December 31, 2019 2018 (Dollars in millions) Assets Current $ 1,477 $ 1,261 Noncurrent 5,725 4,962 Total assets $ 7,202 $ 6,223 Liabilities and Equity Current liabilities $ 625 $ 434 Noncurrent liabilities 1,119 395 Partners' capital and shareholders' equity 5,458 5,394 Total liabilities and equity $ 7,202 $ 6,223 Year Ended December 31, 2019 2018 2017 (Dollars in millions) Results of Operations Revenues $ 6,903 $ 6,777 $ 6,562 Operating expenses 5,022 4,965 4,965 Operating income 1,881 1,812 1,597 Other income (expense), net (22 ) 11 (1 ) Net income $ 1,859 $ 1,823 $ 1,596

Property, Plant and Equipment

Property, Plant and Equipment	12 Months Ended
	Dec. 31, 2019
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	Note 9 Property, Plant and Equipment Property, plant and equipment in service and under construction, and related accumulated depreciation and amortization, as of December 31, 2019 and 2018 , were as follows: December 31, Useful Lives (Years) 2019 2018 (Dollars in millions) Land N/A $ 35 $ 35 Buildings 20 295 296 Leasehold and land improvements 1-30 1,280 1,210 Cell site equipment 7-25 3,708 3,460 Switching equipment 5-8 1,051 1,018 Office furniture and equipment 3-5 280 285 Other operating assets and equipment 3-5 48 51 System development 1-7 1,238 1,149 Work in process N/A 358 274 Total property, plant and equipment, gross 8,293 7,778 Accumulated depreciation and amortization (6,086 ) (5,576 ) Total property, plant and equipment, net $ 2,207 $ 2,202 Depreciation and amortization expense totaled $689 million , $627 million and $604 million in 2019 , 2018 and 2017 , respectively. In 2019 , 2018 and 2017 , (Gain) loss on asset disposals, net included charges of $19 million , $10 million and $17 million , respectively, related to disposals of assets, trade-ins of older assets for replacement assets and other retirements of assets from service in the normal course of business.

Leases

Leases	12 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Leases	Note 10 Leases Change in Accounting Policy In February 2016, the FASB issued Accounting Standards Update 2016-02, Leases and subsequently amended the standard with several Accounting Standards Updates, collectively referred to as ASC 842. This standard replaces the previous lease accounting standard under ASC 840 - Leases and requires lessees to record a right-of-use (ROU) asset and lease liability for the majority of leases. U.S. Cellular adopted the provisions of ASC 842 on January 1, 2019, using a modified retrospective method. Under this method, U.S. Cellular elected to apply the new accounting standard only to the most recent period presented, recognizing the cumulative effect of the accounting change, if any, as an adjustment to the beginning balance of retained earnings. Accordingly, prior periods have not been recast to reflect the new accounting standard. The cumulative effect of applying the provisions of ASC 842 had no material impact on retained earnings. U.S. Cellular elected transitional practical expedients for existing leases which eliminated the requirements to reassess existing lease classification, initial direct costs, and whether contracts contain leases. U.S. Cellular also elected the practical expedient related to land easements that allows it to carry forward the accounting treatment for pre-existing land easement agreements. The cumulative effect of the adoption of ASC 842 on U.S. Cellular’s Consolidated Balance Sheet as of January 1, 2019 is presented below. December 31, 2018 ASC 842 Adjustment January 1, 2019 (Dollars in millions) Prepaid expenses $ 63 $ (13 ) $ 50 Operating lease right-of-use assets — 899 899 Other assets and deferred charges 579 (12 ) 567 Short-term operating lease liabilities — 101 101 Other current liabilities 94 (8 ) 86 Long-term operating lease liabilities — 878 878 Other deferred liabilities and credits 389 (97 ) 292 In connection with the adoption of ASC 842, U.S. Cellular recorded ROU assets and lease liabilities for its operating leases in its Consolidated Balance Sheet as of January 1, 2019. The amounts for ROU assets and lease liabilities initially were calculated as the discounted value of future lease payments. The difference between the ROU assets and the corresponding lease liabilities at January 1, 2019 as shown in the table above resulted from adjustments to ROU assets to account for various lease prepayments and straight-line expense recognition deferral balances which existed as of December 31, 2018. Finance leases are included in Property, plant and equipment and Long-term debt, net consistent with the presentation under prior accounting standards. Lessee Agreements A lease is generally present in a contract if the lessee controls the use of identified property, plant or equipment for a period of time in exchange for consideration. Nearly all of U.S. Cellular’s leases are classified as operating leases, although it does have a small number of finance leases. U.S. Cellular’s most significant leases are for land and tower spaces, network facilities, retail spaces, and offices. U.S. Cellular has agreements with both lease and nonlease components, which are accounted for separately. As part of the present value calculation for the lease liabilities, U.S. Cellular uses an incremental borrowing rate as the rates implicit in the leases are not readily determinable. The incremental borrowing rates used for lease accounting are based on U.S. Cellular's unsecured rates, adjusted to approximate the rates at which U.S. Cellular would be required to borrow on a collateralized basis over a term similar to the recognized lease term. U.S. Cellular applies the incremental borrowing rates to lease components using a portfolio approach based upon the length of the lease term. The cost of nonlease components in U.S. Cellular’s lease portfolio (e.g., utilities and common area maintenance) are not typically predetermined at lease commencement and are expensed as incurred at their relative standalone price. Variable lease expense occurs when, subsequent to the lease commencement, lease payments are made that were not originally included in the lease liability calculation. U.S. Cellular’s variable lease payments are primarily a result of leases with escalations that are tied to an index. The incremental changes due to the index changes are recorded as variable lease expense and are not included in the ROU assets or lease liabilities. The identified lease term determines the periods to which expense is allocated and also has a significant impact on the ROU asset and lease liability calculations. Many of U.S. Cellular’s leases include renewal and early termination options. At lease commencement, the lease terms include options to extend the lease when U.S. Cellular is reasonably certain that it will exercise the options. The lease terms do not include early termination options unless U.S. Cellular is reasonably certain to exercise the options. Certain asset classes have similar lease characteristics; therefore, U.S. Cellular has applied the portfolio approach for lease term recognition for its tower space, retail, and certain ground lease asset classes. The following table shows the components of lease cost included in the Consolidated Statement of Operations: Year Ended (Dollars in millions) Operating lease cost $ 163 Financing lease cost: Amortization of ROU assets 1 Variable lease cost 7 Total lease cost $ 171 The following table shows supplemental cash flow information related to lease activities: Year Ended (Dollars in millions) Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 156 Operating cash flows from finance leases 1 ROU assets obtained in exchange for lease obligations: Operating leases $ 125 The following table shows the classification of U.S. Cellular’s finance leases in its Consolidated Balance Sheet: December 31, 2019 (Dollars in millions) Finance Leases Property, plant and equipment $ 7 Less: Accumulated depreciation and amortization 4 Property, plant and equipment, net $ 3 Current portion of long-term debt 1 Long-term debt, net $ 3 Total finance lease liabilities $ 4 The table below shows a weighted-average analysis for lease terms and discount rates for all leases: December 31, 2019 Weighted Average Remaining Lease Term Operating leases 13 years Finance leases 25 years Weighted Average Discount Rate Operating leases 4.4 Finance leases 7.0 The maturities of lease liabilities are as follows: Operating Leases Finance Leases (Dollars in millions) 2020 $ 144 $ 1 2021 145 — 2022 129 — 2023 112 1 2024 95 1 Thereafter 712 11 Total lease payments 1 $ 1,337 $ 14 Less: Imputed interest 367 10 Present value of lease liabilities $ 970 $ 4 1 Lease payments exclude $ 27 million of legally binding lease payments for leases signed but not yet commenced. Lessor Agreements U.S. Cellular's most significant lessor leases are for tower space. All of U.S. Cellular’s lessor leases are classified as operating leases. A lease is generally present in a contract if the lessee controls the use of identified property, plant, or equipment for a period of time in exchange for consideration. U.S. Cellular’s lessor agreements with lease and nonlease components are generally accounted for separately. The identified lease term determines the periods to which revenue is allocated over the term of the lease. Many of U.S. Cellular’s leases include renewal and early termination options. At lease commencement, lease terms include options to extend the lease when U.S. Cellular is reasonably certain that lessees will exercise the options. Lease terms would not include periods after the date of a termination option that lessees are reasonably certain to exercise. Variable lease income occurs when, subsequent to the lease commencement, lease payments are received that were not originally included in the lease receivable calculation. U.S. Cellular’s variable lease income is primarily a result of leases with escalations that are tied to an index. The incremental increases due to the index changes are recorded as variable lease income. The following table shows the components of lease income which are included in Service revenues in the Consolidated Statement of Operations: Year Ended (Dollars in millions) Operating lease income 1 $ 74 1 During the third quarter of 2019, U.S. Cellular recorded an out-of-period adjustment attributable to 2009 through the second quarter of 2019 due to errors in the timing of recognition of revenue for certain tower leases. This out-of-period adjustment had the impact of increasing operating lease income by $5 million for the year ended December 31, 2019 . U.S. Cellular determined that this adjustment was not material to any of the periods impacted. The maturities of expected lease payments to be received are as follows: Operating Leases (Dollars in millions) 2020 $ 60 2021 55 2022 42 2023 30 2024 15 Thereafter 3 Total future lease maturities $ 205 Disclosures under ASC 840 As of December 31, 2018, future minimum rental payments required under operating leases and rental receipts expected under operating leases that had noncancellable lease terms in excess of one year were as follows: Operating Leases Future Minimum Rental Payments Operating Leases Future Minimum Rental Receipts (Dollars in millions) 2019 $ 154 58 2020 143 47 2021 128 34 2022 112 22 2023 97 10 Thereafter 769 3 Total $ 1,403 174 Rent expense totaled $173 million and $166 million

Asset Retirement Obligation

Asset Retirement Obligation	12 Months Ended
	Dec. 31, 2019
Asset Retirement Obligation [Abstract]
Asset Retirement Obligation	Note 11 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. Asset retirement obligations generally include obligations to restore leased land, towers, 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 2019 and 2018 , 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 2019 and 2018 , were as follows: 2019 2018 (Dollars in millions) Balance at beginning of year $ 203 $ 183 Additional liabilities accrued 2 2 Revisions in estimated cash outflows 2 8 Disposition of assets (1 ) (1 ) Accretion expense 14 12 Transferred to Liabilities held for sale — (1 ) Balance at end of year $ 220 $ 203

Debt

Debt	12 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Debt	Note 12 Debt Revolving Credit Agreement At December 31, 2019 , U.S. Cellular had a revolving credit agreement available for general corporate purposes including spectrum purchases and capital expenditures. Amounts under the revolving credit agreement may be borrowed, repaid and reborrowed from time to time until maturity in May 2023 . As of December 31, 2019 , there were no outstanding borrowings under the revolving credit agreement, except for letters of credit. Interest expense representing commitment fees on the unused portion of the revolving line of credit was $1 million in each of 2019 , 2018 and 2017 . The commitment fees are based on the unsecured senior debt ratings assigned to U.S. Cellular by certain ratings agencies. The following table summarizes the revolving credit agreement as of December 31, 2019 : (Dollars in millions) Maximum borrowing capacity $ 300 Letters of credit outstanding $ 2 Amount borrowed $ — Amount available for use $ 298 Borrowings under the revolving credit agreement bear interest either at a London Inter-bank Offered Rate ( LIBOR) plus 1.75% or at an alternative Base Rate as defined in the revolving credit agreement plus 0.75% , at U.S. Cellular’s option. U.S. Cellular may select a borrowing period of either one, two, three or six months (or other period of twelve months or less if requested by U.S. Cellular and approved by the lenders). U.S. Cellular’s credit spread and commitment fees on its revolving credit agreement may be subject to increase if its current credit rating from nationally recognized credit rating agencies is lowered, and may be subject to decrease if the rating is raised. In connection with U.S. Cellular’s revolving credit agreement, TDS and U.S. Cellular entered into a subordination agreement dated May 10, 2018 , together with the administrative agent for the lenders under U.S. Cellular’s revolving credit agreement. Pursuant to this subordination agreement, (a) any consolidated funded indebtedness from U.S. Cellular to TDS will be unsecured and (b) any (i) consolidated funded indebtedness from U.S. Cellular to TDS (other than “refinancing indebtedness” as defined in the subordination agreement) in excess of $105 million and (ii) refinancing indebtedness in excess of $250 million will be subordinated and made junior in right of payment to the prior payment in full of obligations to the lenders under U.S. Cellular’s revolving credit agreement. As of December 31, 2019 , U.S. Cellular had no outstanding consolidated funded indebtedness or refinancing indebtedness that was subordinated to the revolving credit agreement pursuant to the subordination agreement. The continued availability of the revolving credit agreement requires U.S. Cellular to comply with certain negative and affirmative covenants, maintain certain financial ratios and make representations regarding certain matters at the time of each borrowing. The revolving credit agreement includes the following financial covenants: ▪ Consolidated Interest Coverage Ratio may not be less than 3.00 to 1.00 as of the end of any fiscal quarter. ▪ Consolidated Leverage Ratio may not be greater than the ratios indicated as of the end of any fiscal quarter for each period specified below: Period Ratios From the agreement date of May 10, 2018 through June 30, 2019 3.25 to 1.00 From July 1, 2019 and thereafter 3.00 to 1.00 Certain U.S. Cellular wholly-owned subsidiaries have jointly and severally unconditionally guaranteed the payment and performance of the obligations of U.S. Cellular under the revolving credit agreement pursuant to a guaranty dated May 10, 2018 . Other subsidiaries that meet certain criteria will be required to provide a similar guaranty in the future. U.S. Cellular believes it was in compliance with all of the financial and other covenants and requirements set forth in its revolving credit agreement as of December 31, 2019 . Term Loan In July 2015 , U.S. Cellular borrowed $225 million on a senior term loan credit agreement in two separate draws. This agreement was entered into for general corporate purposes, including working capital, spectrum purchases and capital expenditures. This agreement was entered into in January 2015, amended and restated in June 2016, and further amended in May 2018 and March 2019. The interest rate on outstanding borrowings is reset at one, three or six month intervals at a rate of LIBOR plus 175 basis points. This credit agreement provides for the draws to be continued on a long-term basis under terms that are readily determinable. In October 2019, U.S. Cellular made a $100 million principal prepayment on the senior term loan. The remaining unpaid balance will be due and payable in January 2022 . The senior term loan credit agreement contains financial covenants and subsidiary guarantees that are consistent with the revolving credit agreements described above. U.S. Cellular believes that it was in compliance with all of the financial and other covenants and requirements set forth in its term loan credit agreement as of December 31, 2019 . In connection with U.S. Cellular’s term loan credit agreement, TDS and U.S. Cellular entered into a subordination agreement in June 2016 together with the administrative agent for the lenders under U.S. Cellular’s term loan credit agreement, which is substantially the same as the subordination agreement for U.S. Cellular as described above under the “Revolving Credit Agreement.” As of December 31, 2019 , U.S. Cellular had no outstanding consolidated funded indebtedness or refinancing indebtedness that was subordinated to the term loan agreement pursuant to this subordination agreement. Receivables Securitization Agreement In December 2017, U.S. Cellular, through its subsidiaries, entered into a $200 million credit agreement to permit securitized borrowings using its equipment installment receivables for general corporate purposes, including acquisitions, spectrum purchases and capital expenditures. In connection with the receivables securitization agreement, U.S. Cellular formed a wholly-owned subsidiary, USCC Master Note Trust (Trust), which qualifies as a bankruptcy remote entity. Under the terms of the agreement, U.S. Cellular, through its subsidiaries, transfers eligible equipment installment receivables to the Trust. The Trust then utilizes the transferred assets as collateral for notes payables issued to third party financial institutions. Since U.S. Cellular retains effective control of the transferred assets in the Trust, any activity associated with this receivables securitization agreement will be treated as a secured borrowing. Therefore, U.S. Cellular will continue to report equipment installment receivables and any related balances on the Consolidated Balance Sheet. Cash received from borrowings under the receivables securitization agreement will be reported as Debt. Refer to Note 14 — Variable Interest Entities for additional information. U.S. Cellular entered into a performance guaranty whereby U.S. Cellular guarantees the performance of certain wholly-owned subsidiaries of U.S. Cellular under the receivables securitization agreement. Amounts under the receivables securitization agreement may be borrowed, repaid and reborrowed from time to time until maturity in December 2021, which may be extended from time to time as specified therein. As of December 31, 2019 , there were no outstanding borrowings under the receivables securitization agreement, and the entire unused capacity of $200 million was available, subject to sufficient collateral to satisfy the asset borrowing base provisions of the agreement. Interest expense representing commitment fees on the unused portion of the agreement was $1 million , $1 million and zero for the years 2019 , 2018 and 2017 , respectively. The continued availability of the receivables securitization agreement requires U.S. Cellular to comply with certain negative and affirmative covenants, maintain certain financial ratios and provide representations on certain matters at the time of each borrowing. The covenants include the same financial covenants for U.S. Cellular as described above under the “Revolving Credit Agreement.” U.S. Cellular believes that it was in compliance as of December 31, 2019 , with all of the financial covenants and requirements set forth in its receivables securitization agreement. Other Long-Term Debt Long-term debt as of December 31, 2019 and 2018 , was as follows: December 31, 2019 December 31, 2018 Issuance date Maturity date Call date (any time on or after) Principal Amount Less Unamortized discounts and debt issuance costs Total Principal Amount Less Unamortized discount and debt issuance costs Total (Dollars in millions) Unsecured Senior Notes 6.700% Dec 2003 Dec 2033 Dec 2003 $ 544 $ 13 $ 531 $ 544 $ 14 $ 530 6.950% May 2011 May 2060 May 2016 342 11 331 342 11 331 7.250% Dec 2014 Dec 2063 Dec 2019 275 10 265 275 10 265 7.250% Nov 2015 Dec 2064 Dec 2020 300 10 290 300 10 290 Term Loan Jul 2015 Jan 2022 83 1 82 191 1 190 Finance lease obligations 4 — 4 5 — 5 Installment payment agreement 7 — 7 14 1 13 Total long-term debt $ 1,555 $ 45 $ 1,510 $ 1,671 $ 47 $ 1,624 Long-term debt, current $ 8 $ 19 Long-term debt, noncurrent $ 1,502 $ 1,605 U.S. Cellular may redeem its 6.95% Senior Notes, 7.25% 2063 Senior Notes and 7.25% 2064 Senior Notes, in whole or in part at any time after the respective call date, at a redemption price equal to 100% of the principal amount redeemed plus accrued and unpaid interest. U.S. Cellular may redeem the 6.7% Senior Notes, in whole or in part, at any time prior to maturity at a redemption price equal to the greater of (a) 100% of the principal amount of such notes, plus accrued and unpaid interest, or (b) the sum of the present values of the remaining scheduled payments of principal and interest thereon discounted to the redemption date on a semi-annual basis at the Treasury Rate plus 30 basis points. Interest on the Senior Notes outstanding at December 31, 2019 , is payable quarterly, with the exception of the 6.7% Senior Notes for which interest is payable semi-annually. The annual requirements for principal payments on long-term debt are approximately $8 million , less than $1 million , $83 million , less than $1 million and less than $1 million for the years 2020 through 2024 , respectively. The covenants associated with U.S. Cellular’s long-term debt obligations, among other things, restrict U.S. Cellular’s ability, subject to certain exclusions, to incur additional liens, enter into sale and leaseback transactions, and sell, consolidate or merge assets. U.S. Cellular’s long-term debt notes do not contain any provisions resulting in acceleration of the maturities of outstanding debt in the event of a change in U.S. Cellular’s credit rating.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Note 13 Commitments and Contingencies Purchase Obligations U.S. Cellular has obligations payable under non-cancellable contracts, commitments for device purchases, network facilities and transport services, agreements for software licensing, long-term marketing programs, as well as certain agreements to purchase goods or services. For certain contracts, U.S. Cellular calculates its obligation based on termination fees that can be paid to exit the contract. Future minimum payments required under these commitments as of December 31, 2019 are as follows: Purchase Obligations (Dollars in millions) 2020 $ 924 2021 436 2022 748 2023 61 2024 39 Thereafter 36 Total $ 2,244 Subsequent to December 31, 2019 , U.S. Cellular committed to purchase assets in the amount of $146 million , subject to regulatory approval. This amount is not included in the 2020 purchase obligations above, which are stated as of December 31, 2019 . Indemnifications U.S. Cellular enters into agreements in the normal course of business that provide for indemnification of counterparties. The terms of the indemnifications vary by agreement. The events or circumstances that would require U.S. Cellular to perform under these indemnities are transaction specific; however, these agreements may require U.S. Cellular to indemnify the counterparty for costs and losses incurred from litigation or claims arising from the underlying transaction. U.S. Cellular is unable to estimate the maximum potential liability for these types of indemnifications as the amounts are dependent on the outcome of future events, the nature and likelihood of which cannot be determined at this time. Historically, U.S. Cellular has not made any significant indemnification payments under such agreements. Legal Proceedings U.S. Cellular is involved or may be involved from time to time in legal proceedings before the FCC, other regulatory authorities, and/or various state and federal courts. If U.S. Cellular believes that a loss arising from such legal proceedings is probable and can be reasonably estimated, an amount is accrued in the financial statements for the estimated loss. If only a range of loss can be determined, the best estimate within that range is accrued; if none of the estimates within that range is better than another, the low end of the range is accrued. The assessment of the expected outcomes of legal proceedings is a highly subjective process that requires judgments about future events. The legal proceedings are reviewed at least quarterly to determine the adequacy of accruals and related financial statement disclosures. The ultimate outcomes of legal proceedings could differ materially from amounts accrued in the financial statements. U.S. Cellular has recorded no accrual with respect to legal proceedings and unasserted claims as of December 31, 2019 and 2018 , respectively. In April 2018, the United States Department of Justice (DOJ) notified U.S. Cellular and its parent, TDS, that it was conducting inquiries of U.S. Cellular and TDS under the federal False Claims Act relating to U.S. Cellular’s participation in wireless spectrum license auctions 58, 66, 73 and 97 conducted by the FCC. U.S. Cellular is/was a limited partner in several limited partnerships which qualified for the 25% bid credit in each auction. The investigation arose from civil actions under the Federal False Claims Act brought by private parties in the U.S. District Court for the Western District of Oklahoma. In November and December 2019, following the DOJ’s investigation, the DOJ informed TDS and U.S. Cellular that it would not intervene in the above referenced actions. In addition, on December 5, 2019, the District Court unsealed the complaints. The private party plaintiffs have advised TDS and U.S. Cellular of their intent to pursue the matter and intent to serve the complaint on TDS and U.S. Cellular within the required 90 days of the Court’s unsealing of the complaint. U.S. Cellular believes that its arrangements with the limited partnerships and the limited partnerships’ participation in the FCC auctions complied with applicable law and FCC rules. At this time, U.S. Cellular cannot predict the outcome of any proceeding.

Variable Interest Entities

Variable Interest Entities	12 Months Ended
	Dec. 31, 2019
Variable Interest Entities [Abstract]
Variable Interest Entities	Note 14 Variable Interest Entities Consolidated VIEs U.S. Cellular consolidates VIEs in which it has a controlling financial interest as defined by GAAP and is therefore deemed the primary beneficiary. A controlling financial interest will have both of the following characteristics: (a) the power to direct the VIE activities that most significantly impact economic performance; and (b) the obligation to absorb the VIE losses and the right to receive benefits that are significant to the VIE. U.S. Cellular reviews these criteria initially at the time it enters into agreements and subsequently when events warranting reconsideration occur. These VIEs have risks similar to those described in the “Risk Factors” in U.S. Cellular’s Form 10-K for the year ended December 31, 2019 . During 2017, U.S. Cellular formed USCC EIP LLC (Seller/Sub-Servicer), USCC Receivables Funding LLC (Transferor) and the Trust, collectively the special purpose entities (SPEs), to facilitate a securitized borrowing using its equipment installment plan receivables. Under a Receivables Sale Agreement, U.S. Cellular wholly-owned, majority-owned and unconsolidated entities, collectively referred to as “affiliated entities”, transfer device equipment installment plan contracts to the Seller/Sub-Servicer. The Seller/Sub-Servicer aggregates device equipment installment plan contracts, and performs servicing, collection and all other administrative activities related to accounting for the equipment installment plan contracts. The Seller/Sub-Servicer sells the eligible equipment installment plan receivables to the Transferor, a bankruptcy remote entity, which subsequently sells the receivables to the Trust. The Trust, which is bankruptcy remote and isolated from the creditors of U.S. Cellular, will be responsible for issuing asset-backed variable funding notes (Notes), which are collateralized by the equipment installment plan receivables owned by the Trust. Given that U.S. Cellular has the power to direct the activities of these SPEs, and that these SPEs lack sufficient equity to finance their activities, U.S. Cellular is deemed to have a controlling financial interest in the SPEs and, therefore, consolidates them. All transactions with third parties (e.g., issuance of the asset-backed variable funding notes) will be accounted for as a secured borrowing due to the pledging of equipment installment plan contracts as collateral, significant continuing involvement in the transferred assets, subordinated interests of the cash flows, and continued evidence of control of the receivables. Refer to Note 12 — Debt , Receivables Securitization Agreement for additional details regarding the securitization agreement for which these entities were established. The following VIEs were formed to participate in FCC auctions of wireless spectrum licenses and to fund, establish, and provide wireless service with respect to any FCC wireless spectrum licenses won in the auctions: ▪ Advantage Spectrum, L.P. (Advantage Spectrum) and Sunshine Spectrum, Inc., the general partner of Advantage Spectrum; and ▪ King Street Wireless, L.P. (King Street Wireless) and King Street Wireless, Inc., the general partner of King Street Wireless. These particular VIEs are collectively referred to as designated entities. The power to direct the activities that most significantly impact the economic performance of these VIEs is shared. Specifically, the general partner of these VIEs has the exclusive right to manage, operate and control the limited partnerships and make all decisions to carry on the business of the partnerships. The general partner of each partnership needs the consent of the limited partner, an indirect U.S. Cellular subsidiary, to sell or lease certain wireless spectrum licenses, to make certain large expenditures, admit other partners or liquidate the limited partnerships. Although the power to direct the activities of these VIEs is shared, U.S. Cellular has the most significant level of exposure to the variability associated with the economic performance of the VIEs, indicating that U.S. Cellular is the primary beneficiary of the VIEs. Therefore, in accordance with GAAP, these VIEs are consolidated. U.S. Cellular also consolidates other VIEs that are limited partnerships that provide wireless service. A limited partnership is a variable interest entity unless the limited partners hold substantive participating rights or kick-out rights over the general partner. For certain limited partnerships, U.S. Cellular is the general partner and manages the operations. In these partnerships, the limited partners do not have substantive kick-out or participating rights and, further, such limited partners do not have the authority to remove the general partner. Therefore, these limited partnerships are also recognized as VIEs and are consolidated under the variable interest model. The following table presents the classification and balances of the consolidated VIEs’ assets and liabilities in U.S. Cellular’s Consolidated Balance Sheet. December 31, 2019 2018 (Dollars in millions) Assets Cash and cash equivalents $ 19 $ 9 Short-term investments — 17 Accounts receivable 639 611 Inventory, net 6 5 Other current assets 7 6 Assets held for sale — 4 Licenses 649 652 Property, plant and equipment, net 104 94 Operating lease right-of-use assets 44 — Other assets and deferred charges 346 349 Total assets $ 1,814 $ 1,747 Liabilities Current liabilities $ 32 $ 34 Liabilities held for sale — 1 Long-term operating lease liabilities 41 — Other deferred liabilities and credits 14 16 Total liabilities $ 87 $ 51 Unconsolidated VIEs U.S. Cellular manages the operations of and holds a variable interest in certain other limited partnerships, but is not the primary beneficiary of these entities and, therefore, does not consolidate them under the variable interest model. U.S. Cellular’s total investment in these unconsolidated entities was $5 million and $4 million at December 31, 2019 and 2018 , respectively, and is included in Investments in unconsolidated entities in U.S. Cellular’s Consolidated Balance Sheet. The maximum exposure from unconsolidated VIEs is limited to the investment held by U.S. Cellular in those entities. Other Related Matters U.S. Cellular made contributions, loans and/or advances to its VIEs totaling $255 million , $152 million and $821 million during 2019 , 2018 and 2017 , respectively; of which $214 million in 2019 , $116 million in 2018 and $790 million in 2017 are related to USCC EIP LLC as discussed above. U.S. Cellular may agree to make additional capital contributions and/or advances to these or other VIEs and/or to their general partners to provide additional funding for operations or the development of wireless spectrum licenses granted in various auctions. U.S. Cellular may finance such amounts with a combination of cash on hand, borrowings under its revolving credit agreement and/or other long-term debt. There is no assurance that U.S. Cellular will be able to obtain additional financing on commercially reasonable terms or at all to provide such financial support. The limited partnership agreements of Advantage Spectrum and King Street Wireless also provide the general partner with a put option whereby the general partner may require the limited partner, a subsidiary of U.S. Cellular, to purchase its interest in the limited partnership. The general partner’s put options related to its interests in King Street Wireless became exercisable in 2019. The general partner’s put options related to its interest in Advantage Spectrum will become exercisable in 2021 and 2022. The greater of the carrying value of the general partner's investment or the value of the put option, net of any borrowings due to U.S. Cellular is recorded as Noncontrolling interests with redemption features in U.S. Cellular’s Consolidated Balance Sheet. Also in accordance with GAAP, minority share of income or changes in the redemption value of the put options, net of interest accrued on the loans, are recorded as a component of Net income attributable to noncontrolling interests, net of tax, in U.S. Cellular’s Consolidated Statement of Operations. During the first quarter of 2018, U.S. Cellular recorded an out-of-period adjustment attributable to 2016 and 2017 due to errors in the application of accounting guidance applicable to the calculation of Noncontrolling interests with redemption features related to King Street Wireless, Inc. This out-of-period adjustment had the impact of increasing Net income attributable to noncontrolling interests, net of tax, by $8 million and decreasing Net income attributable to U.S. Cellular shareholders by $8 million in 2018 . U.S. Cellular determined that this adjustment was not material to any of the periods impacted.

Noncontrolling Interests

Noncontrolling Interests	12 Months Ended
	Dec. 31, 2019
Noncontrolling Interest [Abstract]
Noncontrolling Interests	Note 15 Noncontrolling Interests U.S. Cellular’s consolidated financial statements include certain noncontrolling interests that meet the GAAP definition of mandatorily redeemable financial instruments. These mandatorily redeemable noncontrolling interests represent interests held by third parties in consolidated partnerships, where the terms of the underlying partnership agreement provide for a defined termination date at which time the assets of the subsidiary are to be sold, the liabilities are to be extinguished and the remaining net proceeds are to be distributed to the noncontrolling interest holders and U.S. Cellular in accordance with the respective partnership agreements. The termination dates of these mandatorily redeemable noncontrolling interests range from 2085 to 2092 . The estimated aggregate amount that would be due and payable to settle all of these noncontrolling interests, assuming an orderly liquidation of the finite-lived consolidated partnerships on December 31, 2019 , net of estimated liquidation costs, is $36 million . This amount excludes redemption amounts recorded in Noncontrolling interests with redemption features in the Consolidated Balance Sheet. The estimate of settlement value was based on certain factors and assumptions which are subjective in nature. Changes in those factors and assumptions could result in a materially larger or smaller settlement amount. The corresponding carrying value of the mandatorily redeemable noncontrolling interests in finite-lived consolidated partnerships at December 31, 2019 , was $15 million , and is included in Noncontrolling interests in the Consolidated Balance Sheet. The excess of the aggregate settlement value over the aggregate carrying value of these mandatorily redeemable noncontrolling interests is due primarily to the unrecognized appreciation of the noncontrolling interest holders’ share of the underlying net assets in the consolidated partnerships. Neither the noncontrolling interest holders’ share, nor U.S. Cellular’s share, of the appreciation of the underlying net assets of these subsidiaries is reflected in the consolidated financial statements.

Common Shareholders' Equity

Common Shareholders' Equity	12 Months Ended
	Dec. 31, 2019
Stockholders' Equity Note [Abstract]
Common Shareholders' Equity	Note 16 Common Shareholders’ Equity Series A Common Shares Series A Common Shares are convertible on a share-for-share basis into Common Shares. In matters other than the election of directors, each Series A Common Share is entitled to ten votes per share, compared to one vote for each Common Share. The Series A Common Shares are entitled to elect 75% of the directors (rounded down), and the Common Shares elect 25% of the directors (rounded up). As of December 31, 2019 , a majority of U.S. Cellular’s outstanding Common Shares and all of U.S. Cellular’s outstanding Series A Common Shares were held by TDS. Common Share Repurchase Program In November 2009, U.S. Cellular announced by Form 8-K that the Board of Directors of U.S. Cellular authorized the repurchase of up to 1,300,000 Common Shares on an annual basis beginning in 2009 and continuing each year thereafter, on a cumulative basis. In December 2016, the U.S. Cellular Board amended this authorization to provide that, beginning on January 1, 2017, the authorized repurchase amount with respect to a particular year will be any amount from zero to 1,300,000 Common Shares, as determined by the Pricing Committee of the Board of Directors, and that if the Pricing Committee did not specify an amount for any year, such amount would be zero for such year. The Pricing Committee has not specified any increase in the authorization since that time. The Pricing Committee also was authorized to decrease the cumulative amount of the authorization at any time, but has not taken any action to do so at this time. As of December 31, 2019 , the total cumulative amount of Common Shares authorized to be purchased is 5,311,000 . The authorization provides that share repurchases will be made pursuant to open market purchases, block purchases, private purchases, or otherwise, depending on market prices and other conditions. This authorization does not have an expiration date. Pursuant to stock-based compensation plans, U.S. Cellular reissued the following Treasury Shares: Year Ended December 31, 2019 2018 2017 Treasury Shares Reissued 432,000 1,181,000 325,000 Tax-Deferred Savings Plan At December 31, 2019 , U.S. Cellular has reserved 67,000 Common Shares for issuance under the TDS Tax-Deferred Savings Plan, a qualified profit‑sharing plan pursuant to Sections 401(a) and 401(k) of the Internal Revenue Code. Participating employees have the option of investing their contributions in a U.S. Cellular Common Share fund, a TDS Common Share fund or certain unaffiliated funds.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2019
Share-based Payment Arrangement, Noncash Expense [Abstract]
Stock-Based Compensation	Note 17 Stock-Based Compensation U.S. Cellular has established the following stock‑based compensation plans: Long-Term Incentive Plans and a Non-Employee Director compensation plan. Under the U.S. Cellular Long-Term Incentive Plans, U.S. Cellular may grant fixed and performance based incentive and non-qualified stock options, restricted stock, restricted stock units, and deferred compensation stock unit awards to key employees. At December 31, 2019 , the only types of awards outstanding are fixed non-qualified stock option awards, restricted stock unit awards, performance share awards and deferred compensation stock unit awards. Under the Non-Employee Director compensation plan, U.S. Cellular may grant Common Shares to members of the Board of Directors who are not employees of U.S. Cellular or TDS. At December 31, 2019 , U.S. Cellular had reserved 12,867,000 Common Shares for equity awards granted and to be granted under the Long-Term Incentive Plans and 123,000 Common Shares for issuance under the Non-Employee Director compensation plan. U.S. Cellular uses treasury stock to satisfy requirements for Common Shares issued pursuant to its various stock-based compensation plans. Long-Term Incentive Plans – Stock Options Stock options granted to key employees are exercisable over a specified period not in excess of ten years . Stock options generally vest over a period of three years from the date of grant. Stock options outstanding at December 31, 2019 , expire between 2020 and 2026 . However, vested stock options typically expire 30 days after the effective date of an employee’s termination of employment for reasons other than retirement. Employees who leave at the age of retirement have 90 days (or one year if they satisfy certain requirements) within which to exercise their vested stock options. The exercise price of options equals the market value of U.S. Cellular Common Shares on the date of grant. U.S. Cellular did not grant stock option awards in 2019 , 2018 or 2017 . A summary of U.S. Cellular stock options outstanding (total and portion exercisable) and changes during 2019 is presented in the table below: Common Share Options Number of Options Weighted Average Exercise Price Aggregate Intrinsic Value (in millions) Weighted Average Remaining Contractual Life (in years) Outstanding at December 31, 2018 806,000 $ 43.10 (420,000 exercisable) $ 42.39 Exercised (339,000 ) $ 44.27 Expired (7,000 ) $ 45.87 Outstanding at December 31, 2019 460,000 $ 42.20 $ — 4.9 (460,000 exercisable) $ 42.20 $ — 4.9 The aggregate intrinsic value of U.S. Cellular stock options exercised in 2019 , 2018 and 2017 was $3 million , $19 million and $1 million , respectively. The aggregate intrinsic value at December 31, 2019 , presented in the table above represents the total pre-tax intrinsic value (the difference between U.S. Cellular’s closing stock price and the exercise price multiplied by the number of in-the-money options) that would have been received by option holders had all options been exercised on December 31, 2019 . Long-Term Incentive Plans – Restricted Stock Units Restricted stock unit awards granted to key employees generally vest after three years . The restricted stock unit awards currently outstanding were granted in 2017 , 2018 and 2019 and will vest in 2020 , 2021 and 2022 , respectively. U.S. Cellular estimates the fair value of restricted stock units based on the closing market price of U.S. Cellular shares on the date of grant. The fair value is then recognized as compensation cost on a straight-line basis over the requisite service periods of the awards, which is generally the vesting period. A summary of U.S. Cellular nonvested restricted stock units at December 31, 2019 , and changes during the year then ended is presented in the table below: Common Restricted Stock Units Number Weighted Average Grant Date Fair Value Nonvested at December 31, 2018 1,569,000 $ 39.74 Granted 478,000 $ 46.81 Vested (525,000 ) $ 42.99 Forfeited (61,000 ) $ 39.38 Nonvested at December 31, 2019 1,461,000 $ 40.90 The total fair value of restricted stock units that vested during 2019 , 2018 and 2017 was $25 million , $16 million and $11 million , respectively. The weighted average grant date fair value per share of the restricted stock units granted in 2019 , 2018 and 2017 was $46.81 , $38.19 and $38.04 , respectively. Long-Term Incentive Plans – Performance Share Units Beginning in 2017, U.S. Cellular granted performance share units to key employees. The performance share units vest after three years . Each recipient may be entitled to shares of U.S. Cellular common stock equal to 50% to 200% of a communicated target award depending on the achievement of predetermined performance-based operating targets over the performance period, which is a one-year period beginning on January 1 in the year of grant to December 31 in the year of grant. The remaining time through the end of the vesting period is considered the “time-based period”. Performance-based operating targets include Simple Free Cash Flow, Consolidated Total Operating Revenues and Postpaid Handset Voluntary Defections. Subject to vesting during the time-based period, the performance share unit award agreement provides that in no event shall the award be less than 50% of the target opportunity as of the grant date. The performance share units currently outstanding were granted in 2017 , 2018 and 2019 and will vest in 2020 , 2021 and 2022 , respectively. U.S. Cellular estimates the fair value of performance share units using U.S. Cellular’s closing stock price on the date of grant. An estimate of the number of performance share units expected to vest based upon achieving the performance-based operating targets is made and the aggregate fair value is expensed on a straight-line basis over the requisite service period. Each reporting period, during the performance period, the estimate of the number of performance share units expected to vest is reviewed and stock compensation expense is adjusted as appropriate to reflect the revised estimate of the aggregate fair value of the performance share units expected to vest. A summary of U.S. Cellular’s nonvested performance share units and changes during 2019 is presented in the table below: Common Performance Share Units Number Weighted Average Grant Date Fair Value Nonvested at December 31, 2018 768,000 $ 37.78 Granted 323,000 $ 46.43 Vested (5,000 ) $ 37.92 Change in units based on approved performance factors 188,000 $ 38.81 Forfeited (29,000 ) $ 38.55 Nonvested at December 31, 2019 1,245,000 $ 40.16 The total fair value of performance share units vested during 2019 was less than $1 million . No performance share units vested during 2018 or 2017 . The weighted average grant date fair value per share of the performance share units granted in 2019 , 2018 and 2017 was $46.43 , $38.81 and $36.92 , respectively. Long-Term Incentive Plans – Deferred Compensation Stock Units Certain U.S. Cellular employees may elect to defer receipt of all or a portion of their annual bonuses and to receive a company matching contribution on the amount deferred. All bonus compensation that is deferred by employees electing to participate is immediately vested and is deemed to be invested in U.S. Cellular Common Share stock units. The amount of U.S. Cellular’s matching contribution depends on the portion of the annual bonus that is deferred. Participants receive a 25% match for amounts deferred up to 50% of their total annual bonus and a 33% match for amounts that exceed 50% of their total annual bonus; such matching contributions also are deemed to be invested in U.S. Cellular Common Share stock units and vest over three years . The total fair value of deferred compensation stock units that vested during 2019 , 2018 and 2017 was less than $1 million in each respective year. The weighted average grant date fair value per share of the deferred compensation stock units granted in 2018 and 2017 was $40.72 and $36.02 , respectively. There were no deferred compensation stock units granted during 2019 . As of December 31, 2019 , there were 34,000 vested but unissued deferred compensation stock units valued at $1 million . Compensation of Non-Employee Directors U.S. Cellular issued 13,000 , 18,000 and 15,000 Common Shares in 2019 , 2018 and 2017 , respectively, under its Non-Employee Director compensation plan. Stock‑Based Compensation Expense The following table summarizes stock‑based compensation expense recognized during 2019 , 2018 and 2017 : Year Ended December 31, 2019 2018 2017 (Dollars in millions) Stock option awards $ — $ 2 $ 6 Restricted stock unit awards 22 21 19 Performance share unit awards 18 13 4 Awards under Non-Employee Director compensation plan 1 1 1 Total stock-based compensation expense, before income taxes 41 37 30 Income tax benefit (10 ) (9 ) (11 ) Total stock-based compensation expense, net of income taxes $ 31 $ 28 $ 19 The following table provides a summary of the classification of stock-based compensation expense included in the Consolidated Statement of Operations for the years ended: December 31, 2019 2018 2017 (Dollars in millions) Selling, general and administrative expense $ 36 $ 33 $ 27 System operations expense 5 4 3 Total stock-based compensation expense $ 41 $ 37 $ 30 At December 31, 2019 , unrecognized compensation cost for all U.S. Cellular stock‑based compensation awards was $29 million and is expected to be recognized over a weighted average period of 1.8 years. U.S. Cellular’s tax benefits realized from the exercise of stock options and the vesting of other awards totaled $7 million in 2019 .

Supplemental Cash Flow Disclosu

Supplemental Cash Flow Disclosures	12 Months Ended
	Dec. 31, 2019
Supplemental Cash Flow Information [Abstract]
Supplemental Cash Flow Disclosures	Note 18 Supplemental Cash Flow Disclosures Following are supplemental cash flow disclosures regarding interest paid and income taxes paid. Year Ended December 31, 2019 2018 2017 (Dollars in millions) Interest paid $ 107 $ 113 $ 111 Income taxes paid, net of refunds received 78 90 55 Following are supplemental cash flow disclosures regarding transactions related to stock-based compensation awards. In certain situations, U.S. Cellular withholds shares that are issuable upon the exercise of stock options or the vesting of restricted shares to cover, and with a value equivalent to, the exercise price and/or the amount of taxes required to be withheld from the stock award holder at the time of the exercise or vesting. U.S. Cellular then pays the amount of the required tax withholdings to the taxing authorities in cash. Year Ended December 31, 2019 2018 2017 (Dollars in millions) Common Shares withheld 452,000 1,550,000 145,000 Aggregate value of Common Shares withheld $ 23 $ 73 $ 6 Cash receipts upon exercise of stock options 1 29 5 Cash disbursements for payment of taxes (10 ) (11 ) (4 ) Net cash receipts (disbursements) from exercise of stock options and vesting of other stock awards $ (9 ) $ 18 $ 1

Certain Relationships and Relat

Certain Relationships and Related Transactions	12 Months Ended
	Dec. 31, 2019
Related Party Transactions [Abstract]
Certain Relationships and Related Transactions	Note 19 Certain Relationships and Related Transactions The following persons are partners of Sidley Austin LLP, the principal law firm of U.S. Cellular and its subsidiaries: Walter C.D. Carlson, a director of U.S. Cellular, a director and non-executive Chairman of the Board of Directors of TDS and a trustee and beneficiary of a voting trust that controls TDS; and Stephen P. Fitzell, the General Counsel and/or an Assistant Secretary of TDS and U.S. Cellular and certain other subsidiaries of TDS. Walter C.D. Carlson does not provide legal services to TDS, U.S. Cellular or their subsidiaries. U.S. Cellular and its subsidiaries incurred legal costs from Sidley Austin LLP of $7 million , $5 million and $7 million in 2019 , 2018 and 2017 , respectively. U.S. Cellular is billed for all services it receives from TDS, pursuant to the terms of various agreements between it and TDS. These billings are included in U.S. Cellular's Selling, general and administrative expenses. Some of these agreements were established at a time prior to U.S. Cellular's initial public offering when TDS owned more than 90% of U.S. Cellular's outstanding capital stock and may not reflect terms that would be obtainable from an unrelated third party through arms-length negotiations. Billings from TDS and certain of its subsidiaries to U.S. Cellular are based on expenses specifically identified to U.S. Cellular and on allocations of common expenses. Such allocations are based on the relationship of U.S. Cellular's assets, employees, investment in property, plant and equipment and expenses relative to all subsidiaries in the TDS consolidated group. Management believes the method TDS uses to allocate common expenses is reasonable and that all expenses and costs applicable to U.S. Cellular are reflected in its financial statements. Billings to U.S. Cellular from TDS totaled $82 million , $86 million and $85 million in 2019 , 2018 and 2017 , respectively. The Audit Committee of the Board of Directors of U.S. Cellular is responsible for the review and evaluation of all related-party transactions as such term is defined by the rules of the New York Stock Exchange.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies and Recent Accounting Pronouncements (Policies)	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Principles of Consolidation	The accounting policies of U.S. Cellular conform to accounting principles generally accepted in the United States of America (GAAP) as set forth in the Financial Accounting Standards Board (FASB) Accounting Standards Codification (ASC). Unless otherwise specified, references to accounting provisions and GAAP in these notes refer to the requirements of the FASB ASC. The consolidated financial statements include the accounts of U.S. Cellular, subsidiaries in which it has a controlling financial interest, general partnerships in which U.S. Cellular has a majority partnership interest and certain entities in which U.S. Cellular has a variable interest that requires consolidation under GAAP. See Note 14 — Variable Interest Entities for additional information relating to U.S. Cellular’s VIEs. All material intercompany accounts and transactions have been eliminated.
Use of Estimates	The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect (a) the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and (b) the reported amounts of revenues and expenses during the reported period. Actual results could differ from those estimates. Significant estimates are involved in accounting for indefinite-lived intangible assets and income taxes.
Cash, Cash Equivalents and Restricted Cash	Cash and cash equivalents include cash and highly liquid investments with original maturities of three months or less. Cash and cash equivalents subject to contractual restrictions are classified as restricted cash.
Accounts Receivable	Accounts receivable consist primarily of amounts owed by customers for wireless services and equipment sales, including sales of certain devices and accessories under installment plans, by agents for sales of equipment to them and by other wireless carriers whose customers have used U.S. Cellular’s wireless systems.
Allowance for Doubtful Accounts	The allowance for doubtful accounts is the best estimate of the amount of probable credit losses related to existing billed and unbilled accounts receivable. The allowance is estimated based on historical experience, account aging and other factors that could affect collectability. Accounts receivable balances are reviewed on either an aggregate or individual basis for collectability depending on the type of receivable. When it is probable that an account balance will not be collected, the account balance is charged against the allowance for doubtful accounts. U.S. Cellular does not have any off-balance sheet credit exposure related to its customers.
Inventory	Inventory consists primarily of wireless devices stated at the lower of cost, which approximates cost determined on the first-in first-out basis, or net realizable value. Net realizable value is determined by reference to the stand-alone selling price.
Licenses	Licenses consist of direct and incremental costs incurred in acquiring Federal Communications Commission (FCC) wireless spectrum licenses that provide U.S. Cellular with the exclusive right to utilize designated radio spectrum within specific geographic service areas to provide wireless service. Although wireless spectrum licenses are issued for a fixed period of time, generally ten years , or in some cases twelve or fifteen years , the FCC has granted license renewals routinely and at a nominal cost. The wireless spectrum licenses held by U.S. Cellular expire at various dates. U.S. Cellular believes that it is probable that its future wireless spectrum license renewal applications will be granted. U.S. Cellular determined that there are currently no legal, regulatory, contractual, competitive, economic or other factors that limit the useful lives of the wireless spectrum licenses. Therefore, U.S. Cellular has determined that wireless spectrum licenses are indefinite-lived intangible assets. U.S. Cellular performs its annual impairment assessment of wireless spectrum licenses as of November 1 of each year or more frequently if there are events or circumstances that cause U.S. Cellular to believe it is more likely than not that the carrying value of wireless spectrum licenses exceeds fair value. For purposes of its impairment testing, U.S. Cellular separated its FCC wireless spectrum licenses into eight units of accounting. The eight units of accounting consisted of one unit of accounting for developed operating market wireless spectrum licenses (built wireless spectrum licenses) and seven geographic non-operating market wireless spectrum licenses (unbuilt wireless spectrum licenses). U.S. Cellular performed a quantitative impairment assessment in 2019 and a qualitative impairment assessment in 2018 to determine whether the wireless spectrum licenses were impaired. Based on the impairment assessments performed, U.S. Cellular did no t have an impairment of its wireless spectrum licenses in 2019 or 2018
Investments in Unconsolidated Entities	For its equity method investments for which financial information is readily available, U.S. Cellular records its equity in the earnings of the entity in the current period. For its equity method investments for which financial information is not readily available, U.S. Cellular records its equity in the earnings of the entity on a one quarter lag basis.
Property, Plant and Equipment	U.S. Cellular’s Property, plant and equipment is stated at the original cost of construction or purchase including capitalized costs of certain taxes, payroll-related expenses, interest and estimated costs to remove the assets. Expenditures that enhance the productive capacity of assets in service or extend their useful lives are capitalized and depreciated. Expenditures for maintenance and repairs of assets in service are charged to System operations expense or Selling, general and administrative expense, as applicable. Retirements and disposals of assets are recorded by removing the original cost of the asset (along with the related accumulated depreciation) from plant in service and recording it, together with proceeds, if any, and net removal costs (removal costs less an applicable accrued asset retirement obligation and salvage value realized), as a gain or loss, as appropriate. U.S. Cellular capitalizes certain costs of developing new information systems. Software licenses that qualify for capitalization as an asset are accounted for as the acquisition of an intangible asset and the incurrence of a liability to the extent that the license fees are not fully paid at acquisition.
Depreciation and Amortization	Depreciation is provided using the straight-line method over the estimated useful life of the related asset. U.S. Cellular depreciates leasehold improvement assets over periods ranging from one year to thirty years ; such periods approximate the shorter of the assets’ economic lives or the specific lease terms. Useful lives of specific assets are reviewed throughout the year to determine if changes in technology or other business changes would warrant accelerating the depreciation of those specific assets. There were no material changes to the assigned useful lives of the various categories of property, plant and equipment in 2019 , 2018 or 2017 . However, depreciation for certain specific assets was accelerated due to changes in technology. See Note 9 — Property, Plant and Equipment for additional details related to useful lives.
Impairment of Long-Lived Assets	U.S. Cellular reviews long-lived assets for impairment whenever events or changes in circumstances indicate that the assets might be impaired. U.S. Cellular has one asset group for purposes of assessing property, plant and equipment for impairment based on the integrated nature of its assets and operations. The cash flows generated by this single interdependent asset group represent the lowest level for which identifiable cash flows are largely independent of the cash flows of other groups of assets and liabilities.
Leases	A lease is generally present in a contract if the lessee controls the use of identified property, plant or equipment for a period of time in exchange for consideration. See Note 10 — Leases for additional details related to leases.
Agent Liabilities	U.S. Cellular has relationships with agents, which are independent businesses that obtain customers for U.S. Cellular. At December 31, 2019 and 2018 , U.S. Cellular had accrued $59 million and $63 million , respectively, in agent related liabilities. These amounts are included in Other current liabilities in the Consolidated Balance Sheet.
Debt Issuance Costs	Debt issuance costs include underwriters’ and legal fees and other charges related to issuing and renewing various borrowing instruments and other long–term agreements, and are amortized over the respective term of each instrument. Debt issuance costs related to U.S. Cellular’s revolving credit agreement and receivables securitization agreement are recorded in Other assets and deferred charges in the Consolidated Balance Sheet. All other debt issuance costs are presented as an offset to the related debt obligation in the Consolidated Balance Sheet.
Asset Retirement Obligations	U.S. Cellular records asset retirement obligations for the fair value of legal obligations associated with asset retirements and a corresponding increase in the carrying amount of the related long-lived asset in the period in which the obligations are incurred. In periods subsequent to initial measurement, U.S. Cellular recognizes changes in the liability resulting from the passage of time and updates to the timing or the amount of the original estimates. The liability is accreted to its estimated settlement date value over the period to the estimated settlement date. The change in the carrying amount of the long-lived asset is depreciated over the average remaining life of the related asset.
Treasury Shares	Common Shares repurchased by U.S. Cellular are recorded at cost as treasury shares and result in a reduction of equity. When treasury shares are reissued, U.S. Cellular determines the cost using the first-in, first-out cost method. The difference between the cost of the treasury shares and reissuance price is included in Additional paid-in capital or Retained earnings.
Revenue Recognition	Revenues from sales of equipment and products are recognized when control has transferred to the customer, agent or third-party distributor. Service revenues are recognized as the related service is provided. Multiple Performance Obligations U.S. Cellular sells bundled service and equipment offerings. In these instances, U.S. Cellular recognizes its revenue based on the relative standalone selling prices for each distinct service or equipment performance obligation, or bundles thereof. U.S. Cellular estimates the standalone selling price of the device or accessory to be its retail price excluding discounts. U.S. Cellular estimates the standalone selling price of wireless service to be the price offered to customers on month-to-month contracts. Equipment Installment Plans Equipment revenue under equipment installment plan contracts is recognized at the time the device is delivered to the customer for the amount allocated to the equipment. Incentives Discounts, incentives, and rebates to agents and end customers that are deemed cash are recognized as a reduction of Operating revenues concurrently with the associated revenue. From time to time, U.S. Cellular may offer certain promotions to incentivize customers to switch to, or to purchase additional services from, U.S. Cellular. Under these types of promotions, an eligible customer may receive an incentive in the form of a discount off additional services purchased shown as a credit to the customer’s monthly bill. U.S. Cellular accounts for the future discounts as material rights at the time of the initial transaction by allocating and deferring revenue based on the relative proportion of the future discounts in comparison to the aggregate initial purchase. The deferred revenue will be recognized as service revenue in future periods. Amounts Collected from Customers and Remitted to Governmental Authorities U.S. Cellular records amounts collected from customers and remitted to governmental authorities on a net basis within a liability account if the amount is assessed upon the customer and U.S. Cellular merely acts as an agent in collecting the amount on behalf of the imposing governmental authority. If the amount is assessed upon U.S. Cellular, then amounts collected from customers are recorded in Service revenues and amounts remitted to governmental authorities are recorded in Selling, general and administrative expenses in the Consolidated Statement of Operations. The amounts recorded gross in revenues that are billed to customers and remitted to governmental authorities totaled $53 million , $67 million and $58 million for 2019 , 2018 and 2017 , respectively. For contracts that involve multiple element service and equipment offerings, the transaction price is allocated to each performance obligation based on its relative standalone selling price. When payment is collected in advance of delivery of goods or services, a contract liability is recorded. A contract asset is recorded when revenue is recognized in advance of U.S. Cellular’s right to receive consideration. Once there is an unconditional right to receive the consideration, U.S. Cellular bills the customer under the terms of the respective contract and the amounts are recorded as receivables. U.S. Cellular recognizes Equipment sales revenue when the equipment is delivered to the customer and a corresponding contract asset or liability is recorded for the difference between the amount of revenue recognized and the amount billed to the customer in cases where discounts are offered. The contract asset or liability is reduced over the contract term as service is provided and billed to the customer. As a practical expedient, U.S. Cellular groups similar contracts or similar performance obligations together into portfolios of contracts or performance obligations if doing so does not result in a significant difference from accounting for the individual contracts discretely. U.S. Cellular applies this grouping method for the following types of transactions: device activation fees, contract acquisition costs, and certain customer promotions. Contract portfolios are recognized over the respective expected customer lives or terms of the contracts. The following is a description of principal activities from which U.S. Cellular generates its revenues. Services and products Nature, timing of satisfaction of performance obligations, and significant payment terms Wireless services Wireless service includes voice, messaging and data services. Revenue is recognized in Service revenues as wireless service is provided to the customer. Wireless services generally are billed and paid in advance on a monthly basis. Wireless devices and accessories U.S. Cellular offers a comprehensive range of wireless devices such as handsets, tablets, mobile hotspots, home phones and routers for use by its customers, as well as accessories. U.S. Cellular also sells wireless devices to agents and other third-party distributors for resale. U.S. Cellular frequently discounts wireless devices sold to new and current customers. U.S. Cellular also offers customers the option to purchase certain devices and accessories under installment contracts over a specified time period. For certain equipment installment plans, after a specified period of time, the customer may have the right to upgrade to a new device. Such upgrades require the customer to enter into an equipment installment contract for the new device, and transfer the existing device to U.S. Cellular. U.S. Cellular recognizes revenue in Equipment sales revenues when control of the device or accessory is transferred to the customer, agent or third-party distributor, which is generally upon delivery. Wireless roaming U.S. Cellular receives roaming revenues when other wireless carriers’ customers use U.S. Cellular’s wireless systems. U.S. Cellular recognizes revenue in Service revenues when the roaming service is provided. Wireless Eligible Telecommunications Carrier (ETC) Revenues Telecommunications companies may be designated by states, or in some cases by the FCC, as an ETC to receive support payments from the Universal Service Fund if they provide specified services in “high cost” areas. ETC revenues recognized in the reporting period represent the amounts which U.S. Cellular is entitled to receive for such period, as determined and approved in connection with U.S. Cellular’s designation as an ETC in various states. Wireless tower rents U.S. Cellular receives tower rental revenues when another carrier leases tower space on a U.S. Cellular owned tower. U.S. Cellular recognizes revenue in Service revenues in the period during which the services are provided. Significant Judgments Revenues from sales of equipment are recognized when control has transferred to the customer, agent or third-party distributor. Service revenues are recognized as the related service is provided. Services are deemed to be highly interrelated when the method and timing of transfer and performance risk are the same. Highly interrelated services that are determined to not be distinct have been grouped into a single performance obligation. Each month of services promised is a performance obligation. The series of monthly service performance obligations promised over the course of the contract are combined into a single performance obligation for purposes of the allocation. U.S. Cellular has made judgments regarding transaction price, including but not limited to issues relating to variable consideration, time value of money and returns. When determined to be significant in the context of the contract, these items are considered in the valuation of transaction price at contract inception or modification, as appropriate.
Advertising Costs	U.S. Cellular expenses advertising costs as incurred. Advertising costs totaled $212 million , $215 million and $211 million in 2019 , 2018 and 2017 , respectively.
Income Taxes	U.S. Cellular is included in a consolidated federal income tax return with other members of the TDS consolidated group. For financial statement purposes, U.S. Cellular and its subsidiaries calculate their income, income taxes and credits as if they comprised a separate affiliated group. Under a tax allocation agreement between TDS and U.S. Cellular, U.S. Cellular remits its applicable income tax payments to TDS. U.S. Cellular had a tax receivable balance with TDS of $46 million and $14 million as of December 31, 2019 , and 2018 , respectively.
Stock-Based Compensation and Other Plans	U.S. Cellular has established a long-term incentive plan and a non-employee director compensation plan. These plans are considered compensatory plans and, therefore, recognition of costs for grants made under these plans is required.
Defined Contribution Plans	U.S. Cellular participates in a qualified noncontributory defined contribution pension plan sponsored by TDS; such plan provides pension benefits for the employees of U.S. Cellular and its subsidiaries. Under this plan, pension benefits and costs are calculated separately for each participant and are funded currently. Pension costs were $11 million in 2019 , 2018 and 2017 . U.S. Cellular also participates in a defined contribution retirement savings plan (401(k) plan) sponsored by TDS. Total costs incurred for U.S. Cellular’s contributions to the 401(k) plan were $14 million , $15 million and $16 million in 2019 , 2018 and 2017 , respectively.
Recently Adopted and Recently Issued Accounting Pronouncements	In June 2016, the FASB issued Accounting Standards Update 2016-13, Financial Instruments - Credit Losses: Measurement of Credit Losses on Financial Instruments (ASU 2016-13). ASU 2016-13 requires entities to use a new forward-looking, expected loss model to estimate credit losses. It also requires additional disclosure relating to the credit quality of trade and other receivables, including information relating to management’s estimate of credit allowances. U.S. Cellular is required to adopt ASU 2016-13 on January 1, 2020, using the modified retrospective approach. The adoption of ASU 2016-13 is not expected to have a significant impact on U.S. Cellular's financial position or results of operations. In August 2018, the FASB issued Accounting Standards Update 2018-15, Intangibles - Goodwill and Other - Internal-Use Software: Customer's Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract (ASU 2018-15). ASU 2018-15 aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the existing guidance for capitalizing implementation costs for an arrangement that has a software license. The service element of a hosting arrangement will continue to be expensed as incurred. Any capitalized implementation costs will be amortized over the period of the service contract. U.S. Cellular is required to adopt ASU 2018-15 on January 1, 2020, either retrospectively or prospectively to eligible costs incurred on or after the date that this guidance is first applied. The adoption of ASU 2018-15 is not expected to have a significant impact on U.S. Cellular's financial position or results of operations. In February 2016, the FASB issued Accounting Standards Update 2016-02, Leases and subsequently amended the standard with several Accounting Standards Updates, collectively referred to as ASC 842. This standard replaces the previous lease accounting standard under ASC 840 - Leases and requires lessees to record a right-of-use (ROU) asset and lease liability for the majority of leases. U.S. Cellular adopted the provisions of ASC 842 on January 1, 2019, using a modified retrospective method. Under this method, U.S. Cellular elected to apply the new accounting standard only to the most recent period presented, recognizing the cumulative effect of the accounting change, if any, as an adjustment to the beginning balance of retained earnings. Accordingly, prior periods have not been recast to reflect the new accounting standard. The cumulative effect of applying the provisions of ASC 842 had no material impact on retained earnings.
Legal proceedings	U.S. Cellular is involved or may be involved from time to time in legal proceedings before the FCC, other regulatory authorities, and/or various state and federal courts. If U.S. Cellular believes that a loss arising from such legal proceedings is probable and can be reasonably estimated, an amount is accrued in the financial statements for the estimated loss. If only a range of loss can be determined, the best estimate within that range is accrued; if none of the estimates within that range is better than another, the low end of the range is accrued. The assessment of the expected outcomes of legal proceedings is a highly subjective process that requires judgments about future events. The legal proceedings are reviewed at least quarterly to determine the adequacy of accruals and related financial statement disclosures. The ultimate outcomes of legal proceedings could differ materially from amounts accrued in the financial statements.
Variable Interest Entities	U.S. Cellular consolidates VIEs in which it has a controlling financial interest as defined by GAAP and is therefore deemed the primary beneficiary. A controlling financial interest will have both of the following characteristics: (a) the power to direct the VIE activities that most significantly impact economic performance; and (b) the obligation to absorb the VIE losses and the right to receive benefits that are significant to the VIE. U.S. Cellular reviews these criteria initially at the time it enters into agreements and subsequently when events warranting reconsideration occur. These VIEs have risks similar to those described in the “Risk Factors” in U.S. Cellular’s Form 10-K for the year ended December 31, 2019 .

Summary of Significant Accoun_3

Summary of Significant Accounting Policies and Recent Accounting Pronouncements (Tables)	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Reconciliation of cash, cash equivalents and restricted cash	The following table provides a reconciliation of Cash and cash equivalents and restricted cash reported in the Consolidated Balance Sheet to the total of the amounts in the Consolidated Statement of Cash Flows. December 31, 2019 2018 (Dollars in millions) Cash and cash equivalents $ 285 $ 580 Restricted cash included in Other current assets 6 3 Cash, cash equivalents and restricted cash in the statement of cash flows $ 291 $ 583

Revenue Recognition (Tables)

Revenue Recognition (Tables)	12 Months Ended
	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Schedule of Multiple-deliverable Arrangements	The following is a description of principal activities from which U.S. Cellular generates its revenues. Services and products Nature, timing of satisfaction of performance obligations, and significant payment terms Wireless services Wireless service includes voice, messaging and data services. Revenue is recognized in Service revenues as wireless service is provided to the customer. Wireless services generally are billed and paid in advance on a monthly basis. Wireless devices and accessories U.S. Cellular offers a comprehensive range of wireless devices such as handsets, tablets, mobile hotspots, home phones and routers for use by its customers, as well as accessories. U.S. Cellular also sells wireless devices to agents and other third-party distributors for resale. U.S. Cellular frequently discounts wireless devices sold to new and current customers. U.S. Cellular also offers customers the option to purchase certain devices and accessories under installment contracts over a specified time period. For certain equipment installment plans, after a specified period of time, the customer may have the right to upgrade to a new device. Such upgrades require the customer to enter into an equipment installment contract for the new device, and transfer the existing device to U.S. Cellular. U.S. Cellular recognizes revenue in Equipment sales revenues when control of the device or accessory is transferred to the customer, agent or third-party distributor, which is generally upon delivery. Wireless roaming U.S. Cellular receives roaming revenues when other wireless carriers’ customers use U.S. Cellular’s wireless systems. U.S. Cellular recognizes revenue in Service revenues when the roaming service is provided. Wireless Eligible Telecommunications Carrier (ETC) Revenues Telecommunications companies may be designated by states, or in some cases by the FCC, as an ETC to receive support payments from the Universal Service Fund if they provide specified services in “high cost” areas. ETC revenues recognized in the reporting period represent the amounts which U.S. Cellular is entitled to receive for such period, as determined and approved in connection with U.S. Cellular’s designation as an ETC in various states. Wireless tower rents U.S. Cellular receives tower rental revenues when another carrier leases tower space on a U.S. Cellular owned tower. U.S. Cellular recognizes revenue in Service revenues in the period during which the services are provided.
Disaggregation of Revenues	In the following table, U.S. Cellular's revenues are disaggregated by type of service, which represents the relevant categorization of revenues for U.S. Cellular, and timing of recognition. Service revenues are recognized over time and Equipment sales are point in time. Year Ended Year Ended December 31, 2018 (Dollars in millions) Revenues from contracts with customers: Retail service $ 2,650 $ 2,623 Inbound roaming 174 154 Other service 137 135 Service revenues from contracts with customers 2,961 2,912 Equipment sales 987 989 Total revenues from contracts with customers 1 $ 3,948 $ 3,901 1 Revenue line items in this table will not agree to amounts presented in the Consolidated Statement of Operations as the amounts in this table only include revenue resulting from contracts with customers.
Contract with Customer, Assets and Liabilities	The following table provides balances for contract assets from contracts with customers, which are recorded in Other current assets and Other assets and deferred charges in the Consolidated Balance Sheet, and contract liabilities from contracts with customers, which are recorded in Customer deposits and deferred revenues and Other deferred liabilities and credits in the Consolidated Balance Sheet. December 31, 2019 December 31, 2018 (Dollars in millions) Contract assets $ 7 $ 9 Contract liabilities 1 $ 154 $ 147 1 The contract liability balance at December 31, 2018 differs from the amount reported in Note 2 — Revenue Recognition of the 2018 Form 10-K, as the previously reported amount included certain lease-related balances that did not result from contracts with customers.
Remaining Performance Obligations	The following table includes estimated service revenues expected to be recognized related to performance obligations that are unsatisfied (or partially unsatisfied) at the end of the reporting period. These estimates represent service revenues to be recognized when wireless services are delivered to customers pursuant to service plan contracts and under certain roaming agreements with other carriers. These estimates are based on contracts in place as of December 31, 2019 , and may vary from actual results. As practical expedients, revenue related to contracts of less than one year, generally month-to-month contracts, and contracts with a fixed per-unit price and variable quantity, are excluded from these estimates. Service Revenues (Dollars in millions) 2020 $ 206 2021 90 Thereafter 160 Total $ 456

Fair Value Measurements (Table)

Fair Value Measurements (Table)	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Fair value measurements	U.S. Cellular has applied the provisions of fair value accounting for purposes of computing the fair value of financial instruments for disclosure purposes as displayed below. Level within the Fair Value Hierarchy December 31, 2019 December 31, 2018 Book Value Fair Value Book Value Fair Value (Dollars in millions) Cash and cash equivalents 1 $ 285 $ 285 $ 580 $ 580 Short-term investments 1 — — 17 17 Long-term debt Retail 2 917 943 917 850 Institutional 2 534 594 534 531 Other 2 83 83 180 180

Equipment Installment Plans (Ta

Equipment Installment Plans (Table)	12 Months Ended
	Dec. 31, 2019
Receivables [Abstract]
Equipment installment plan receivables	The following table summarizes equipment installment plan receivables as of December 31, 2019 and 2018 . December 31, 2019 2018 (Dollars in millions) Equipment installment plan receivables, gross $ 1,008 $ 974 Allowance for credit losses (84 ) (77 ) Equipment installment plan receivables, net $ 924 $ 897 Net balance presented in the Consolidated Balance Sheet as: Accounts receivable — Customers and agents (Current portion) $ 587 $ 560 Other assets and deferred charges (Non-current portion) 337 337 Equipment installment plan receivables, net $ 924 $ 897
Equipment installment plan receivables credit categories	The balance and aging of the equipment installment plan receivables on a gross basis by current credit category were as follows: December 31, 2019 December 31, 2018 Lower Risk Higher Risk Total Lower Risk Higher Risk Total (Dollars in millions) Unbilled $ 931 $ 11 $ 942 $ 904 $ 17 $ 921 Billed — current 44 1 45 35 1 36 Billed — past due 20 1 21 15 2 17 Equipment installment plan receivables, gross $ 995 $ 13 $ 1,008 $ 954 $ 20 $ 974
Equipment installment plans allowance for credit losses	The activity in the allowance for credit losses for equipment installment plan receivables was as follows: 2019 2018 (Dollars in millions) Allowance for credit losses, beginning of year $ 77 $ 65 Bad debts expense 82 71 Write-offs, net of recoveries (75 ) (59 ) Allowance for credit losses, end of year $ 84 $ 77

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Income taxes receivable (payable)	U.S. Cellular’s current income taxes balances at December 31, 2019 and 2018 , were as follows: December 31, 2019 2018 (Dollars in millions) Federal income taxes receivable $ 44 $ 15 Net state income taxes receivable 2 —
Income tax expense (benefit)	Income tax expense (benefit) is summarized as follows: Year Ended December 31, 2019 2018 2017 (Dollars in millions) Current Federal $ 44 $ 48 $ 68 State 12 6 10 Deferred Federal — (5 ) (354 ) State (4 ) 2 (11 ) Total income tax expense (benefit) $ 52 $ 51 $ (287 )
Income tax reconciliation	A reconciliation of U.S. Cellular’s income tax expense computed at the statutory rate to the reported income tax expense, and the statutory federal income tax rate to U.S. Cellular’s effective income tax rate is as follows: Year Ended December 31, 2019 2018 2017 Amount Rate Amount Rate Amount Rate (Dollars in millions) Statutory federal income tax expense and rate $ 39 21.0 % $ 45 21.0 % $ (95 ) 35.0 % State income taxes, net of federal benefit 1 6 3.4 9 4.0 (4 ) 1.4 Effect of noncontrolling interests (1 ) (0.5 ) (1 ) (0.4 ) (2 ) 0.8 Federal income tax rate change 2 — — (4 ) (2.0 ) (254 ) 93.3 Change in federal valuation allowance 3 7 3.6 (1 ) (0.3 ) (5 ) 1.9 Goodwill impairment 4 — — — — 71 (26.2 ) Nondeductible compensation 2 1.3 4 1.8 4 (1.5 ) Tax credits (3 ) (1.5 ) — (0.1 ) — 0.1 Other differences, net 2 0.8 (1 ) (0.3 ) (2 ) 0.7 Total income tax expense (benefit) and rate $ 52 28.1 % $ 51 23.7 % $ (287 ) 105.5 % 1 State income taxes, net of federal benefit, include changes in unrecognized tax benefits as well as adjustments to the valuation allowance. 2 The Tax Act reduced the federal income tax rate from 35% to 21% for years after 2017. The $4 million tax benefit in 2018 relates primarily to finalizing the analysis for 2017 depreciation deductions as described above. The $254 million tax benefit in 2017 related to adjusting the deferred tax liability to the lower tax rate upon enactment of the Tax Act. 3 Change in federal valuation allowance in 2019 is due primarily to interest expense carryforwards not expected to be realized. The 2018 change also includes a change in judgment related to net operating loss carryforwards that are now realizable due to an internal restructuring. 4 Goodwill impairment reflects an adjustment to increase 2017 income tax expense by $71 million related to a portion of the impaired goodwill that is not amortizable for income tax purposes. See Note 7 — Intangible Assets for additional information related to the goodwill impairment.
Deferred income tax assets and liabilities	Significant components of U.S. Cellular’s deferred income tax assets and liabilities at December 31, 2019 and 2018 , were as follows 1 : December 31, 2019 2018 (Dollars in millions) Deferred tax assets Net operating loss (NOL) carryforwards $ 96 $ 96 Lease liabilities 230 — Asset retirement obligation 45 43 Other 84 114 Total deferred tax assets 455 253 Less valuation allowance (90 ) (75 ) Net deferred tax assets 365 178 Deferred tax liabilities Property, plant and equipment 284 299 Licenses/intangibles 230 207 Partnership investments 131 133 Lease assets 206 — Other 21 49 Total deferred tax liabilities 872 688 Net deferred income tax liability $ 507 $ 510
Deferred tax valuation allowance	A summary of U.S. Cellular’s deferred tax asset valuation allowance is as follows: 2019 2018 2017 (Dollars in millions) Balance at beginning of year $ 75 $ 77 $ 65 Charged to income tax expense 15 5 12 Charged to Retained earnings — (7 ) — Balance at end of year $ 90 $ 75 $ 77
Income tax unrecognized benefits summary	A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows: 2019 2018 2017 (Dollars in millions) Unrecognized tax benefits balance at beginning of year $ 48 $ 47 $ 43 Additions for tax positions of current year 7 6 6 Additions for tax positions of prior years — 1 1 Reductions for tax positions of prior years (6 ) — (1 ) Reductions for settlements of tax positions (1 ) — — Reductions for lapses in statutes of limitations — (6 ) (2 ) Unrecognized tax benefits balance at end of year $ 48 $ 48 $ 47

Earnings Per Share (Tables)

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2019
Earnings Per Share [Abstract]
Earnings per share	The amounts used in computing basic and diluted earnings per share attributable to U.S. Cellular shareholders were as follows: Year Ended December 31, 2019 2018 2017 (Dollars and shares in millions, except per share amounts) Net income attributable to U.S. Cellular shareholders $ 127 $ 150 $ 12 Weighted average number of shares used in basic earnings per share 86 86 85 Effects of dilutive securities 2 1 1 Weighted average number of shares used in diluted earnings per share 88 87 86 Basic earnings per share attributable to U.S. Cellular shareholders $ 1.47 $ 1.75 $ 0.14 Diluted earnings per share attributable to U.S. Cellular shareholders $ 1.44 $ 1.72 $ 0.14

Intangible Assets (Tables)

Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Licenses	Activity related to U.S. Cellular's Licenses is presented below. 2019 2018 (Dollars in millions) Balance at beginning of year $ 2,186 $ 2,223 Acquisitions 267 8 Transferred to Assets held for sale — (51 ) Divestitures (10 ) (11 ) Exchanges - Licenses received 26 18 Exchanges - Licenses surrendered — (1 ) Capitalized interest 2 — Balance at end of year $ 2,471 $ 2,186

Investments in Unconsolidated_2

Investments in Unconsolidated Entities (Tables)	12 Months Ended
	Dec. 31, 2019
Equity Method Investments and Joint Ventures [Abstract]
Equity and measurement alternative method investments	U.S. Cellular's Investments in unconsolidated entities are accounted for using either the equity method or measurement alternative method as shown in the table below. The carrying value of measurement alternative method investments represents cost minus any impairments plus or minus any observable price changes. December 31, 2019 2018 (Dollars in millions) Equity method investments: Capital contributions, loans, advances and adjustments $ 105 $ 105 Cumulative share of income 2,060 1,892 Cumulative share of distributions (1,725 ) (1,563 ) Total equity method investments 440 434 Measurement alternative method investments 7 7 Total investments in unconsolidated entities $ 447 $ 441 The following tables, which are based on information provided in part by third parties, summarize the combined assets, liabilities and equity, and results of operations of U.S. Cellular’s equity method investments: December 31, 2019 2018 (Dollars in millions) Assets Current $ 1,477 $ 1,261 Noncurrent 5,725 4,962 Total assets $ 7,202 $ 6,223 Liabilities and Equity Current liabilities $ 625 $ 434 Noncurrent liabilities 1,119 395 Partners' capital and shareholders' equity 5,458 5,394 Total liabilities and equity $ 7,202 $ 6,223
Equity method investments, summarized results of operations	Year Ended December 31, 2019 2018 2017 (Dollars in millions) Results of Operations Revenues $ 6,903 $ 6,777 $ 6,562 Operating expenses 5,022 4,965 4,965 Operating income 1,881 1,812 1,597 Other income (expense), net (22 ) 11 (1 ) Net income $ 1,859 $ 1,823 $ 1,596

Property, Plant and Equipment (

Property, Plant and Equipment (Table)	12 Months Ended
	Dec. 31, 2019
Property, Plant and Equipment [Abstract]
Property, plant and equipment	Property, plant and equipment in service and under construction, and related accumulated depreciation and amortization, as of December 31, 2019 and 2018 , were as follows: December 31, Useful Lives (Years) 2019 2018 (Dollars in millions) Land N/A $ 35 $ 35 Buildings 20 295 296 Leasehold and land improvements 1-30 1,280 1,210 Cell site equipment 7-25 3,708 3,460 Switching equipment 5-8 1,051 1,018 Office furniture and equipment 3-5 280 285 Other operating assets and equipment 3-5 48 51 System development 1-7 1,238 1,149 Work in process N/A 358 274 Total property, plant and equipment, gross 8,293 7,778 Accumulated depreciation and amortization (6,086 ) (5,576 ) Total property, plant and equipment, net $ 2,207 $ 2,202

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Schedule of new accounting pronouncements and changes in accounting principles	The cumulative effect of the adoption of ASC 842 on U.S. Cellular’s Consolidated Balance Sheet as of January 1, 2019 is presented below. December 31, 2018 ASC 842 Adjustment January 1, 2019 (Dollars in millions) Prepaid expenses $ 63 $ (13 ) $ 50 Operating lease right-of-use assets — 899 899 Other assets and deferred charges 579 (12 ) 567 Short-term operating lease liabilities — 101 101 Other current liabilities 94 (8 ) 86 Long-term operating lease liabilities — 878 878 Other deferred liabilities and credits 389 (97 ) 292
Components of lease expense	The following table shows the components of lease cost included in the Consolidated Statement of Operations: Year Ended (Dollars in millions) Operating lease cost $ 163 Financing lease cost: Amortization of ROU assets 1 Variable lease cost 7 Total lease cost $ 171
Supplemental cash flow information related to leases	The following table shows supplemental cash flow information related to lease activities: Year Ended (Dollars in millions) Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 156 Operating cash flows from finance leases 1 ROU assets obtained in exchange for lease obligations: Operating leases $ 125
Supplemental balance sheet information related to leases	The following table shows the classification of U.S. Cellular’s finance leases in its Consolidated Balance Sheet: December 31, 2019 (Dollars in millions) Finance Leases Property, plant and equipment $ 7 Less: Accumulated depreciation and amortization 4 Property, plant and equipment, net $ 3 Current portion of long-term debt 1 Long-term debt, net $ 3 Total finance lease liabilities $ 4
Schedule of weighted average remaining lease term and weighted average discount rate related to leases	The table below shows a weighted-average analysis for lease terms and discount rates for all leases: December 31, 2019 Weighted Average Remaining Lease Term Operating leases 13 years Finance leases 25 years Weighted Average Discount Rate Operating leases 4.4 Finance leases 7.0
Maturities of lease liabilities	The maturities of lease liabilities are as follows: Operating Leases Finance Leases (Dollars in millions) 2020 $ 144 $ 1 2021 145 — 2022 129 — 2023 112 1 2024 95 1 Thereafter 712 11 Total lease payments 1 $ 1,337 $ 14 Less: Imputed interest 367 10 Present value of lease liabilities $ 970 $ 4 1 Lease payments exclude $ 27 million of legally binding lease payments for leases signed but not yet commenced.
Lease income	The following table shows the components of lease income which are included in Service revenues in the Consolidated Statement of Operations: Year Ended (Dollars in millions) Operating lease income 1 $ 74 1 During the third quarter of 2019, U.S. Cellular recorded an out-of-period adjustment attributable to 2009 through the second quarter of 2019 due to errors in the timing of recognition of revenue for certain tower leases. This out-of-period adjustment had the impact of increasing operating lease income by $5 million for the year ended December 31, 2019 . U.S. Cellular determined that this adjustment was not material to any of the periods impacted.
Maturities of expected lease revenues	The maturities of expected lease payments to be received are as follows: Operating Leases (Dollars in millions) 2020 $ 60 2021 55 2022 42 2023 30 2024 15 Thereafter 3 Total future lease maturities $ 205
Lease commitments	Disclosures under ASC 840 As of December 31, 2018, future minimum rental payments required under operating leases and rental receipts expected under operating leases that had noncancellable lease terms in excess of one year were as follows: Operating Leases Future Minimum Rental Payments Operating Leases Future Minimum Rental Receipts (Dollars in millions) 2019 $ 154 58 2020 143 47 2021 128 34 2022 112 22 2023 97 10 Thereafter 769 3 Total $ 1,403 174

Asset Retirement Obligation (Ta

Asset Retirement Obligation (Table)	12 Months Ended
	Dec. 31, 2019
Asset Retirement Obligation [Abstract]
Asset retirement obligations	In 2019 and 2018 , 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 2019 and 2018 , were as follows: 2019 2018 (Dollars in millions) Balance at beginning of year $ 203 $ 183 Additional liabilities accrued 2 2 Revisions in estimated cash outflows 2 8 Disposition of assets (1 ) (1 ) Accretion expense 14 12 Transferred to Liabilities held for sale — (1 ) Balance at end of year $ 220 $ 203

Debt (Table)

Debt (Table)	12 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Revolving credit facilities	The following table summarizes the revolving credit agreement as of December 31, 2019 : (Dollars in millions) Maximum borrowing capacity $ 300 Letters of credit outstanding $ 2 Amount borrowed $ — Amount available for use $ 298
Financial covenants	The revolving credit agreement includes the following financial covenants: ▪ Consolidated Interest Coverage Ratio may not be less than 3.00 to 1.00 as of the end of any fiscal quarter. ▪ Consolidated Leverage Ratio may not be greater than the ratios indicated as of the end of any fiscal quarter for each period specified below: Period Ratios From the agreement date of May 10, 2018 through June 30, 2019 3.25 to 1.00 From July 1, 2019 and thereafter 3.00 to 1.00
Long-term debt	Long-term debt as of December 31, 2019 and 2018 , was as follows: December 31, 2019 December 31, 2018 Issuance date Maturity date Call date (any time on or after) Principal Amount Less Unamortized discounts and debt issuance costs Total Principal Amount Less Unamortized discount and debt issuance costs Total (Dollars in millions) Unsecured Senior Notes 6.700% Dec 2003 Dec 2033 Dec 2003 $ 544 $ 13 $ 531 $ 544 $ 14 $ 530 6.950% May 2011 May 2060 May 2016 342 11 331 342 11 331 7.250% Dec 2014 Dec 2063 Dec 2019 275 10 265 275 10 265 7.250% Nov 2015 Dec 2064 Dec 2020 300 10 290 300 10 290 Term Loan Jul 2015 Jan 2022 83 1 82 191 1 190 Finance lease obligations 4 — 4 5 — 5 Installment payment agreement 7 — 7 14 1 13 Total long-term debt $ 1,555 $ 45 $ 1,510 $ 1,671 $ 47 $ 1,624 Long-term debt, current $ 8 $ 19 Long-term debt, noncurrent $ 1,502 $ 1,605

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Purchase Obligations	Future minimum payments required under these commitments as of December 31, 2019 are as follows: Purchase Obligations (Dollars in millions) 2020 $ 924 2021 436 2022 748 2023 61 2024 39 Thereafter 36 Total $ 2,244

Variable Interest Entities (Tab

Variable Interest Entities (Tables)	12 Months Ended
	Dec. 31, 2019
Variable Interest Entities [Abstract]
Consolidated VIE assets and liabilities	The following table presents the classification and balances of the consolidated VIEs’ assets and liabilities in U.S. Cellular’s Consolidated Balance Sheet. December 31, 2019 2018 (Dollars in millions) Assets Cash and cash equivalents $ 19 $ 9 Short-term investments — 17 Accounts receivable 639 611 Inventory, net 6 5 Other current assets 7 6 Assets held for sale — 4 Licenses 649 652 Property, plant and equipment, net 104 94 Operating lease right-of-use assets 44 — Other assets and deferred charges 346 349 Total assets $ 1,814 $ 1,747 Liabilities Current liabilities $ 32 $ 34 Liabilities held for sale — 1 Long-term operating lease liabilities 41 — Other deferred liabilities and credits 14 16 Total liabilities $ 87 $ 51

Common Shareholders' Equity (Ta

Common Shareholders' Equity (Table)	12 Months Ended
	Dec. 31, 2019
Stockholders' Equity Note [Abstract]
Treasury shares reissued	Pursuant to stock-based compensation plans, U.S. Cellular reissued the following Treasury Shares: Year Ended December 31, 2019 2018 2017 Treasury Shares Reissued 432,000 1,181,000 325,000

Stock-Based Compensation (Table

Stock-Based Compensation (Table)	12 Months Ended
	Dec. 31, 2019
Share-based Payment Arrangement, Noncash Expense [Abstract]
Summary of stock options	A summary of U.S. Cellular stock options outstanding (total and portion exercisable) and changes during 2019 is presented in the table below: Common Share Options Number of Options Weighted Average Exercise Price Aggregate Intrinsic Value (in millions) Weighted Average Remaining Contractual Life (in years) Outstanding at December 31, 2018 806,000 $ 43.10 (420,000 exercisable) $ 42.39 Exercised (339,000 ) $ 44.27 Expired (7,000 ) $ 45.87 Outstanding at December 31, 2019 460,000 $ 42.20 $ — 4.9 (460,000 exercisable) $ 42.20 $ — 4.9
Summary of nonvested restricted stock units	A summary of U.S. Cellular nonvested restricted stock units at December 31, 2019 , and changes during the year then ended is presented in the table below: Common Restricted Stock Units Number Weighted Average Grant Date Fair Value Nonvested at December 31, 2018 1,569,000 $ 39.74 Granted 478,000 $ 46.81 Vested (525,000 ) $ 42.99 Forfeited (61,000 ) $ 39.38 Nonvested at December 31, 2019 1,461,000 $ 40.90
Summary of nonvested performance share units	A summary of U.S. Cellular’s nonvested performance share units and changes during 2019 is presented in the table below: Common Performance Share Units Number Weighted Average Grant Date Fair Value Nonvested at December 31, 2018 768,000 $ 37.78 Granted 323,000 $ 46.43 Vested (5,000 ) $ 37.92 Change in units based on approved performance factors 188,000 $ 38.81 Forfeited (29,000 ) $ 38.55 Nonvested at December 31, 2019 1,245,000 $ 40.16
Stock-based compensation	The following table summarizes stock‑based compensation expense recognized during 2019 , 2018 and 2017 : Year Ended December 31, 2019 2018 2017 (Dollars in millions) Stock option awards $ — $ 2 $ 6 Restricted stock unit awards 22 21 19 Performance share unit awards 18 13 4 Awards under Non-Employee Director compensation plan 1 1 1 Total stock-based compensation expense, before income taxes 41 37 30 Income tax benefit (10 ) (9 ) (11 ) Total stock-based compensation expense, net of income taxes $ 31 $ 28 $ 19
Stock-based compensation, allocation by financial statement line item	The following table provides a summary of the classification of stock-based compensation expense included in the Consolidated Statement of Operations for the years ended: December 31, 2019 2018 2017 (Dollars in millions) Selling, general and administrative expense $ 36 $ 33 $ 27 System operations expense 5 4 3 Total stock-based compensation expense $ 41 $ 37 $ 30

Supplemental Cash Flow Disclo_2

Supplemental Cash Flow Disclosures (Table)	12 Months Ended
	Dec. 31, 2019
Supplemental Cash Flow Information [Abstract]
Supplemental cash flow disclosures	Following are supplemental cash flow disclosures regarding interest paid and income taxes paid. Year Ended December 31, 2019 2018 2017 (Dollars in millions) Interest paid $ 107 $ 113 $ 111 Income taxes paid, net of refunds received 78 90 55
Stock-based compensation supplemental cash flows	Following are supplemental cash flow disclosures regarding transactions related to stock-based compensation awards. In certain situations, U.S. Cellular withholds shares that are issuable upon the exercise of stock options or the vesting of restricted shares to cover, and with a value equivalent to, the exercise price and/or the amount of taxes required to be withheld from the stock award holder at the time of the exercise or vesting. U.S. Cellular then pays the amount of the required tax withholdings to the taxing authorities in cash. Year Ended December 31, 2019 2018 2017 (Dollars in millions) Common Shares withheld 452,000 1,550,000 145,000 Aggregate value of Common Shares withheld $ 23 $ 73 $ 6 Cash receipts upon exercise of stock options 1 29 5 Cash disbursements for payment of taxes (10 ) (11 ) (4 ) Net cash receipts (disbursements) from exercise of stock options and vesting of other stock awards $ (9 ) $ 18 $ 1

Summary of Significant Accoun_4

Summary of Significant Accounting Policies and Recent Accounting Pronouncements - Narrative (Details) connection in Millions	12 Months Ended
	Dec. 31, 2019USD ($)segmentconnectionunitasset_group	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	May 04, 1988
Accounting Policy Disclosures [Line Items]
Number of connections | connection	4.9
Number of reportable segments | segment	1
FCC Licenses, period of renewal	12 years
FCC Licenses, number of accounting units | unit	8
FCC Licenses, number of accounting units, built licenses | unit	1
FCC Licenses, number of accounting units, unbuilt licenses | unit	7
Asset groups | asset_group	1
Agent liability	$ 59,000,000	$ 63,000,000
Advertising costs	$ 212,000,000	215,000,000	$ 211,000,000
Minimum
Accounting Policy Disclosures [Line Items]
FCC Licenses, period of renewal	10 years
Maximum
Accounting Policy Disclosures [Line Items]
FCC Licenses, period of renewal	15 years
Leasehold and land improvements | Minimum
Accounting Policy Disclosures [Line Items]
Useful life	1 year
Leasehold and land improvements | Maximum
Accounting Policy Disclosures [Line Items]
Useful life	30 years
Pension
Accounting Policy Disclosures [Line Items]
Defined contribution cost	$ 11,000,000	11,000,000	11,000,000
401(k)
Accounting Policy Disclosures [Line Items]
Defined contribution cost	14,000,000	15,000,000	$ 16,000,000
TDS
Accounting Policy Disclosures [Line Items]
Income taxes receivable	46,000,000	14,000,000
Licenses
Accounting Policy Disclosures [Line Items]
Impairment of intangible assets	$ 0	$ 0
U.S. Cellular | TDS
Accounting Policy Disclosures [Line Items]
TDS ownership of U.S. Cellular	82.00%
U.S. Cellular | TDS | Minimum
Accounting Policy Disclosures [Line Items]
TDS ownership of U.S. Cellular				90.00%

Summary of Significant Accoun_5

Summary of Significant Accounting Policies and Recent Accounting Pronouncements - Restricted Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accounting Policies [Abstract]
Cash and cash equivalents	$ 285	$ 580
Restricted cash included in Other current assets	6	3
Cash, cash equivalents and restricted cash in the statement of cash flows	$ 291	$ 583	$ 352	$ 586

Revenue Recognition - Narrative

Revenue Recognition - Narrative (Details) - USD ($) $ in Millions	Jan. 01, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jan. 01, 2018
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Change in accounting policy			$ 2	$ 176
Amounts recorded gross in revenues that are billed to customers and remitted to governmental authorities		$ 53	67	58
Revenue recognized	$ 128
Capitalized contract cost
Capitalized contract cost related to commission fees		133	139
Amortization of contract cost assets		$ 109	108
Retained earnings
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Change in accounting policy			$ 2	$ 175
ASC 606 | Retained earnings
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Change in accounting policy					$ 175

Revenue Recognition - Disaggreg

Revenue Recognition - Disaggregation Of Revenue (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 3,948	$ 3,901
Transferred over time
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	2,961	2,912
Transferred over time | Retail service
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	2,650	2,623
Transferred over time | Inbound roaming
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	174	154
Transferred over time | Other service
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	137	135
Transferred at point in time | Equipment sales
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 987	$ 989

Revenue Recognition - Contract

Revenue Recognition - Contract Assets and Contract Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Revenue from Contract with Customer [Abstract]
Contract assets	$ 7	$ 9
Contract liabilities	$ 154	$ 147

Revenue Recognition - Performan

Revenue Recognition - Performance Obligations (Details) $ in Millions	Dec. 31, 2019USD ($)
Revenue from Contract with Customer [Abstract]
Remaining performance obligation amount	$ 456
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Revenue from Contract with Customer [Abstract]
Remaining performance obligation amount	$ 206
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected timing of remaining performance obligation, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue from Contract with Customer [Abstract]
Remaining performance obligation amount	$ 90
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected timing of remaining performance obligation, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue from Contract with Customer [Abstract]
Remaining performance obligation amount	$ 160
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected timing of remaining performance obligation, period

Fair Value Measurements - Finan

Fair Value Measurements - Financial Instruments (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Financial Instruments
Cash and cash equivalents	$ 285	$ 580
Short-term investments	0	17
Book Value
Financial Instruments
Cash and cash equivalents	285	580
Short-term investments	0	17
Book Value | Retail
Financial Instruments
Long-term debt	917	917
Book Value | Institutional
Financial Instruments
Long-term debt	534	534
Book Value | Other
Financial Instruments
Long-term debt	83	180
Fair Value | Level 1
Financial Instruments
Cash and cash equivalents	285	580
Short-term investments	0	17
Fair Value | Level 2 | Retail
Financial Instruments
Long-term debt	943	850
Fair Value | Level 2 | Institutional
Financial Instruments
Long-term debt	594	531
Fair Value | Level 2 | Other
Financial Instruments
Long-term debt	$ 83	$ 180
7.25% 2063 Senior Notes
Financial Instruments
Interest rate on debt	7.25%
7.25% 2064 Senior Notes
Financial Instruments
Interest rate on debt	7.25%
6.95% Senior Notes
Financial Instruments
Interest rate on debt	6.95%
6.7% Senior Notes
Financial Instruments
Interest rate on debt	6.70%
Interest rate | Minimum | Institutional and Other
Financial Instruments
Fair value assumption, interest rate	3.55%	5.03%
Interest rate | Maximum | Institutional and Other
Financial Instruments
Fair value assumption, interest rate	5.73%	6.97%

Equipment Installment Plans - E

Equipment Installment Plans - EIP Receivables (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Equipment installment plan receivables, gross	$ 1,008	$ 974
Allowance for credit losses	(84)	(77)
Equipment installment plan receivables, net	924	897
Accounts receivable — Customers and agents (Current portion)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Equipment installment plan receivables, net	587	560
Other assets and deferred charges (Non-current portion)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Equipment installment plan receivables, net	$ 337	$ 337

Equipment Installment Plans - G

Equipment Installment Plans - Gross Receivables by Credit Category (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Financing Receivable, Credit Quality Indicator [Line Items]
Equipment installment plan receivables, gross	$ 1,008	$ 974
Unbilled
Financing Receivable, Credit Quality Indicator [Line Items]
Equipment installment plan receivables	942	921
Billed
Financing Receivable, Credit Quality Indicator [Line Items]
Equipment installment plan receivables	45	36
Equipment installment plan receivables, past due	21	17
Lower Risk
Financing Receivable, Credit Quality Indicator [Line Items]
Equipment installment plan receivables, gross	995	954
Lower Risk | Unbilled
Financing Receivable, Credit Quality Indicator [Line Items]
Equipment installment plan receivables	931	904
Lower Risk | Billed
Financing Receivable, Credit Quality Indicator [Line Items]
Equipment installment plan receivables	44	35
Equipment installment plan receivables, past due	20	15
Higher Risk
Financing Receivable, Credit Quality Indicator [Line Items]
Equipment installment plan receivables, gross	13	20
Higher Risk | Unbilled
Financing Receivable, Credit Quality Indicator [Line Items]
Equipment installment plan receivables	11	17
Higher Risk | Billed
Financing Receivable, Credit Quality Indicator [Line Items]
Equipment installment plan receivables	1	1
Equipment installment plan receivables, past due	$ 1	$ 2

Equipment Installment Plans - A

Equipment Installment Plans - Allowance for Credit Losses (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Allowance for credit losses
Allowance for credit losses, beginning of year	$ 77
Allowance for credit losses, end of year	84	$ 77
Equipment installment plan receivable
Allowance for credit losses
Allowance for credit losses, beginning of year	77	65
Bad debts expense	82	71
Write-offs, net of recoveries	(75)	(59)
Allowance for credit losses, end of year	$ 84	$ 77

Income Taxes - Balances (Detail

Income Taxes - Balances (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Income Tax [Line Items]
Income taxes receivable	$ 46	$ 15
Federal
Income Tax [Line Items]
Income taxes receivable	44	15
State
Income Tax [Line Items]
Income taxes receivable	$ 2	$ 0

Income Taxes - Expense (Benefit

Income Taxes - Expense (Benefit) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current
Current federal income tax expense	$ 44	$ 48	$ 68
Current state income tax expense	12	6	10
Deferred
Deferred federal income tax expense (benefit)	0	(5)	(354)
Deferred state income tax expense (benefit)	(4)	2	(11)
Total income tax expense (benefit)	$ 52	$ 51	$ (287)

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax [Line Items]
Income tax benefit, adjustment		$ 4
Other income tax disclosures
Effect of unrecognized tax benefit on income tax expense	$ 37	38	$ 38
Interest and penalties expense related to unrecognized income tax expense (benefit)	3		$ 3
Net accrued interest and penalties	21	19
Maximum
Other income tax disclosures
Interest and penalties expense related to unrecognized income tax expense (benefit)		$ (1)
State
Other income tax disclosures
NOL carryforwards	1,895
Deferred income tax asset for State NOL carryforwards	86
Federal
Other income tax disclosures
Deferred tax asset for Federal NOL carryforward	$ 10

Income Taxes - Expense Reconcil

Income Taxes - Expense Reconciliation (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Amount
Statutory federal income tax expense	$ 39	$ 45	$ (95)
State income taxes, net of federal benefit	6	9	(4)
Effect of noncontrolling interests	(1)	(1)	(2)
Federal income tax rate change	0	(4)	(254)
Change in federal valuation allowance	7	(1)	(5)
Goodwill impairment	0	0	71
Nondeductible compensation	2	4	4
Tax credits	(3)	0	0
Other differences, net	2	(1)	(2)
Total income tax expense (benefit)	$ 52	$ 51	$ (287)
Rate
Statutory federal income tax rate	21.00%	21.00%	35.00%
State income taxes, net of federal benefit	3.40%	4.00%	1.40%
Effect of noncontrolling interests	(0.50%)	(0.40%)	0.80%
Federal income tax rate change	0.00%	(2.00%)	93.30%
Change in federal valuation allowance	3.60%	(0.30%)	1.90%
Goodwill impairment	0.00%	0.00%	(26.20%)
Nondeductible compensation	1.30%	1.80%	(1.50%)
Tax credits	(1.50%)	(0.10%)	0.10%
Other differences, net	0.80%	(0.30%)	0.70%
Total income tax rate	28.10%	23.70%	105.50%

Income Taxes - Components of De

Income Taxes - Components of Deferred Income Tax (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets
Net operating loss (NOL) carryforwards	$ 96	$ 96
Lease liabilities	230	0
Asset retirement obligation	45	43
Other	84	114
Total deferred tax assets	455	253
Less valuation allowance	(90)	(75)
Net deferred tax assets	365	178
Deferred tax liabilities
Property, plant and equipment	284	299
Licenses/intangibles	230	207
Partnership investments	131	133
Lease assets	206	0
Other	21	49
Total deferred tax liabilities	872	688
Net deferred income tax liability	$ 507	$ 510

Income Taxes - Deferred Tax Val

Income Taxes - Deferred Tax Valuation Allowance (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Deferred tax valuation allowance, rollfoward
Balance at beginning of year	$ 75
Balance at end of year	90	$ 75
Deferred tax asset valuation allowance
Deferred tax valuation allowance, rollfoward
Balance at beginning of year	75	77	$ 65
Charged to income tax expense	15	5	12
Charged to Retained earnings	0	(7)	0
Balance at end of year	$ 90	$ 75	$ 77

Income Taxes - Unrecognized Tax

Income Taxes - Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Summary of unrecognized income tax benefits
Unrecognized tax benefits balance at beginning of year	$ 48	$ 47	$ 43
Additions for tax positions of current year	7	6	6
Additions for tax positions of prior years	0	1	1
Reductions for tax positions of prior years	(6)	0	(1)
Reductions for settlements of tax positions	(1)	0	0
Reductions for lapses in statutes of limitations	0	(6)	(2)
Unrecognized tax benefits balance at end of year	$ 48	$ 48	$ 47

Earnings Per Share - Computatio

Earnings Per Share - Computation (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Earnings Per Share, Basic [Abstract]
Net income attributable to U.S. Cellular shareholders	$ 127	$ 150	$ 12
Weighted average number of shares used in basic earnings per share (in shares)	86	86	85
Effects of dilutive securities (in shares)	2	1	1
Weighted average number of shares used in diluted earnings per share (in shares)	88	87	86
Basic earnings per share attributable to U.S. Cellular shareholders (in dollars per share)	$ 1.47	$ 1.75	$ 0.14
Diluted earnings per share attributable to U.S. Cellular shareholders (in dollars per share)	$ 1.44	$ 1.72	$ 0.14

Earnings Per Share - Narrative

Earnings Per Share - Narrative (Details) - shares shares in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (in shares)		2	3
Maximum
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (in shares)	1

Intangible Assets - Schedules (

Intangible Assets - Schedules (Details) - Licenses - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Licenses
Balance at beginning of year	$ 2,186	$ 2,223
Acquisitions	267	8
Transferred to Assets held for sale	0	(51)
Divestitures	(10)	(11)
Exchanges - Licenses received	26	18
Exchanges - Licenses surrendered	0	(1)
Capitalized interest	2	0
Balance at end of year	$ 2,471	$ 2,186

Intangible Assets - Narrative (

Intangible Assets - Narrative (Details)	12 Months Ended
	Dec. 31, 2019USD ($)license	Dec. 31, 2017USD ($)
Indefinite-lived Intangible Assets [Line Items]
Total winning bid	$ 256,000,000
Goodwill
Loss on impairment		$ 370,000,000
Goodwill		$ 0
Auction 101
Indefinite-lived Intangible Assets [Line Items]
Licenses won | license	408
Auction 102
Indefinite-lived Intangible Assets [Line Items]
Licenses won | license	282

Investments in Unconsolidated_3

Investments in Unconsolidated Entities (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Equity method investments:
Capital contributions, loans, advances and adjustments	$ 105	$ 105
Cumulative share of income	2,060	1,892
Cumulative share of distributions	(1,725)	(1,563)
Total equity method investments	440	434
Measurement alternative method investments	7	7
Total investments in unconsolidated entities	447	441
Assets
Current	1,477	1,261
Noncurrent	5,725	4,962
Total assets	7,202	6,223
Liabilities and Equity
Current liabilities	625	434
Noncurrent liabilities	1,119	395
Partners' capital and shareholders' equity	5,458	5,394
Total liabilities and equity	7,202	6,223
Results of Operations
Revenues	6,903	6,777	$ 6,562
Operating expenses	5,022	4,965	4,965
Operating income	1,881	1,812	1,597
Other income (expense), net	(22)	11	(1)
Net income	$ 1,859	$ 1,823	$ 1,596

Property, Plant and Equipment_2

Property, Plant and Equipment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Land	$ 35	$ 35
Buildings	295	296
Leasehold and land improvements	1,280	1,210
Cell site equipment	3,708	3,460
Switching equipment	1,051	1,018
Office furniture and equipment	280	285
Other operating assets and equipment	48	51
System development	1,238	1,149
Work in process	358	274
Total property, plant and equipment, gross	8,293	7,778
Accumulated depreciation and amortization	(6,086)	(5,576)
Property, plant and equipment, net	2,207	2,202
Depreciation and amortization expense	689	627	$ 604
Loss on asset disposals	$ 19	$ 10	$ 17
Buildings
Property, Plant and Equipment [Line Items]
Useful life	20 years
Leasehold and land improvements | Minimum
Property, Plant and Equipment [Line Items]
Useful life	1 year
Leasehold and land improvements | Maximum
Property, Plant and Equipment [Line Items]
Useful life	30 years
Cell site equipment | Minimum
Property, Plant and Equipment [Line Items]
Useful life	7 years
Cell site equipment | Maximum
Property, Plant and Equipment [Line Items]
Useful life	25 years
Switching equipment | Minimum
Property, Plant and Equipment [Line Items]
Useful life	5 years
Switching equipment | Maximum
Property, Plant and Equipment [Line Items]
Useful life	8 years
Office furniture and equipment | Minimum
Property, Plant and Equipment [Line Items]
Useful life	3 years
Office furniture and equipment | Maximum
Property, Plant and Equipment [Line Items]
Useful life	5 years
Other operating assets and equipment | Minimum
Property, Plant and Equipment [Line Items]
Useful life	3 years
Other operating assets and equipment | Maximum
Property, Plant and Equipment [Line Items]
Useful life	5 years
System development | Minimum
Property, Plant and Equipment [Line Items]
Useful life	1 year
System development | Maximum
Property, Plant and Equipment [Line Items]
Useful life	7 years

Leases - Narrative (Details)

Leases - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Jan. 01, 2019
Leases
Cumulative effect of accounting change	$ 2,000,000	$ 176,000,000
Rent expense	173,000,000	166,000,000
Retained earnings
Leases
Cumulative effect of accounting change	$ 2,000,000	$ 175,000,000
Minimum | ASC 842 | Retained earnings
Leases
Cumulative effect of accounting change			$ 0

Leases - Consolidated Balance S

Leases - Consolidated Balance Sheet (Details) - USD ($) $ in Millions	Dec. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Leases - Consolidated Balance Sheet
Prepaid expenses	$ 50	$ 50	$ 63
Operating lease right-of-use assets	900	899	0
Other assets and deferred charges	566	567	579
Short-term operating lease liabilities	105	101	0
Other current liabilities	79	86	94
Long-term operating lease liabilities	865	878	0
Other deferred liabilities and credits	$ 319	292	$ 389
ASC 842 Adjustment
Leases - Consolidated Balance Sheet
Prepaid expenses		(13)
Operating lease right-of-use assets		899
Other assets and deferred charges		(12)
Short-term operating lease liabilities		101
Other current liabilities		(8)
Long-term operating lease liabilities		878
Other deferred liabilities and credits		$ (97)

Leases - Lease Cost (Details)

Leases - Lease Cost (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019USD ($)
Lease, Cost [Abstract]
Operating lease cost	$ 163
Amortization of ROU assets	1
Variable lease cost	7
Total lease cost	$ 171

Leases - Supplemental Cash Flow

Leases - Supplemental Cash Flow Information (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019USD ($)
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$ 156
Operating cash flows from finance leases	1
ROU assets obtained in exchange for lease obligations:
Operating leases	$ 125

Leases - Classification of Fina

Leases - Classification of Finance Leases (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Finance Leases
Property, plant and equipment	$ 8,293	$ 7,778
Less: Accumulated depreciation and amortization	6,086	5,576
Property, plant and equipment, net	2,207	2,202
Current portion of long-term debt	8	19
Long-term debt, net	1,502	$ 1,605
Total finance lease liabilities	4
Finance leases
Finance Leases
Property, plant and equipment	7
Less: Accumulated depreciation and amortization	4
Property, plant and equipment, net	3
Current portion of long-term debt	1
Long-term debt, net	3
Total finance lease liabilities	$ 4

Leases - Lease Term and Discoun

Leases - Lease Term and Discount Rate (Details)	Dec. 31, 2019
Weighted Average Remaining Lease Term
Operating leases	13 years
Finance leases	25 years
Weighted Average Discount Rate
Operating leases	4.40%
Finance leases	7.00%

Leases - Maturities of Lease Li

Leases - Maturities of Lease Liabilities (Details) $ in Millions	Dec. 31, 2019USD ($)
Operating Leases Future Minimum Rental Payments
2020	$ 144
2021	145
2022	129
2023	112
2024	95
Thereafter	712
Total lease payments	1,337
Less: Imputed interest	367
Present value of lease liabilities	970
Finance Leases
2020	1
2021	0
2022	0
2023	1
2024	1
Thereafter	11
Total lease payments	14
Less: Imputed interest	10
Present value of lease liabilities	4
Legally binding lease payments for leases signed but not yet commenced	$ 27

Leases - Components of Lease In

Leases - Components of Lease Income (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019USD ($)
Leases
Operating lease income	$ 74
Tower leases out of period adjustment
Leases
Immaterial error correction	During the third quarter of 2019, U.S. Cellular recorded an out-of-period adjustment attributable to 2009 through the second quarter of 2019 due to errors in the timing of recognition of revenue for certain tower leases. This out-of-period adjustment had the impact of increasing operating lease income by $5 million for the year ended December 31, 2019. U.S. Cellular determined that this adjustment was not material to any of the periods impacted.
Other service revenues | Tower leases out of period adjustment
Leases
Out-of-period adjustment	$ 5

Leases - Maturities of Expected

Leases - Maturities of Expected Lease Revenues (Details) $ in Millions	Dec. 31, 2019USD ($)
Leases [Abstract]
2020	$ 60
2021	55
2022	42
2023	30
2024	15
Thereafter	3
Total future lease maturities	$ 205

Leases - Minimum Lease Obligati

Leases - Minimum Lease Obligations (Details) $ in Millions	Dec. 31, 2018USD ($)
Operating Leases Future Minimum Rental Payments
2019	$ 154
2020	143
2021	128
2022	112
2023	97
Thereafter	769
Total	1,403
Operating Leases Future Minimum Rental Receipts
2019	58
2020	47
2021	34
2022	22
2023	10
Thereafter	3
Total	$ 174

Asset Retirement Obligation (De

Asset Retirement Obligation (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Asset retirement obligation
Balance at beginning of year	$ 203	$ 183
Additional liabilities accrued	2	2
Revisions in estimated cash outflows	2	8
Disposition of assets	(1)	(1)
Accretion expense	14	12
Transferred to Liabilities held for sale	0	(1)
Balance at end of year	$ 220	$ 203

Debt - Revolving Credit Facilit

Debt - Revolving Credit Facilities (Details)	12 Months Ended
	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Jul. 01, 2019	Jun. 30, 2019
U.S. Cellular Revolving credit facility
Debt Instrument [Line Items]
Unused commitment fees	$ 1,000,000	$ 1,000,000	$ 1,000,000
Revolving credit
Maximum borrowing capacity	300,000,000
Letters of credit outstanding	2,000,000
Amounts borrowed	0
Amount available for use	$ 298,000,000
Consolidated interest coverage ratio	3
Consolidated leverage ratio				3	3.25
U.S. Cellular Revolving credit facility | LIBOR rate
Revolving credit
Contractual spread	1.75%
U.S. Cellular Revolving credit facility | Alternative Base Rate
Revolving credit
Contractual spread	0.75%
Maximum | Subordinated Agreement
Revolving credit
Consolidated funded indebtedness	$ 105,000,000
Refinancing indebtedness	250,000,000
Subordinated Agreement | U.S. Cellular Revolving credit facility
Revolving credit
Consolidated funded indebtedness	0
Refinancing indebtedness	$ 0

Debt - Term Loan Facility (Deta

Debt - Term Loan Facility (Details) - USD ($)	Oct. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Jul. 31, 2015
Long-term debt
Principal amount		$ 1,555,000,000	$ 1,671,000,000
U.S. Cellular Term loan facility
Long-term debt
Principal amount		83,000,000	$ 191,000,000	$ 225,000,000
Principal prepayment	$ 100,000,000
Subordinated Agreement | U.S. Cellular Term loan facility
Debt Instrument [Line Items]
Consolidated funded indebtedness		0
Refinancing indebtedness		$ 0
LIBOR rate | U.S. Cellular Term loan facility
Debt Instrument [Line Items]
Contractual spread		1.75%

Debt - Receivables Securitizati

Debt - Receivables Securitization Agreement (Details) - Receivables securitization facility - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 200		$ 200
Amounts borrowed	0
Unused commitment fees	$ 1	$ 1	$ 0

Debt - Long-term Debt (Details)

Debt - Long-term Debt (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Jul. 31, 2015
Long-term debt
Principal amount	$ 1,555,000,000	$ 1,671,000,000
Unamortized discount and debt issuance costs	45,000,000	47,000,000
Total long-term debt	1,510,000,000	1,624,000,000
Current portion of long-term debt	8,000,000	19,000,000
Long-term debt, net	1,502,000,000	1,605,000,000
Long-term debt maturities
Scheduled principal payments 2020	8,000,000
Scheduled principal payments 2022	$ 83,000,000
6.7% Senior Notes
Long-term debt
Interest rate on debt	6.70%
Redemption price, percentage	100.00%
Principal amount	$ 544,000,000	544,000,000
Unamortized discount and debt issuance costs	13,000,000	14,000,000
Long term debt	$ 531,000,000	530,000,000
6.95% Senior Notes
Long-term debt
Interest rate on debt	6.95%
Principal amount	$ 342,000,000	342,000,000
Unamortized discount and debt issuance costs	11,000,000	11,000,000
Long term debt	$ 331,000,000	331,000,000
7.25% 2063 Senior Notes
Long-term debt
Interest rate on debt	7.25%
Principal amount	$ 275,000,000	275,000,000
Unamortized discount and debt issuance costs	10,000,000	10,000,000
Long term debt	$ 265,000,000	265,000,000
7.25% 2064 Senior Notes
Long-term debt
Interest rate on debt	7.25%
Principal amount	$ 300,000,000	300,000,000
Unamortized discount and debt issuance costs	10,000,000	10,000,000
Long term debt	$ 290,000,000	290,000,000
Callable Notes
Long-term debt
Redemption price, percentage	100.00%
U.S. Cellular Term loan facility
Long-term debt
Principal amount	$ 83,000,000	191,000,000	$ 225,000,000
Unamortized discount and debt issuance costs	1,000,000	1,000,000
Long term debt	82,000,000	190,000,000
Finance lease obligations
Long-term debt
Principal amount	4,000,000	5,000,000
Unamortized discount and debt issuance costs	0	0
Finance lease obligations	4,000,000	5,000,000
Installment payment agreement
Long-term debt
Principal amount	7,000,000	14,000,000
Unamortized discount and debt issuance costs	0	1,000,000
Long term debt	7,000,000	$ 13,000,000
Maximum
Long-term debt maturities
Scheduled principal payments 2021	1,000,000
Scheduled principal payments 2023	1,000,000
Scheduled principal payments 2024	$ 1,000,000
Treasury Rate | 6.7% Senior Notes
Long-term debt
Contractual spread	0.30%

Commitments and Contingencies -

Commitments and Contingencies - Purchase Obligations (Details) $ in Millions	Dec. 31, 2019USD ($)
Purchase Obligations
2020	$ 924
2021	436
2022	748
2023	61
2024	39
Thereafter	36
Total	$ 2,244

Commitments and Contingencies_2

Commitments and Contingencies - Narrative (Details) - USD ($) $ in Millions	Feb. 25, 2020	Dec. 31, 2019	Dec. 31, 2018
Loss Contingency, Estimate [Abstract]
Accrual for legal proceedings and unasserted claims		$ 0	$ 0
FCC license auction, percent of bid credit in each auction			25.00%
Subsequent Event
Long-term Purchase Commitment [Line Items]
Commitment to purchase assets	$ 146

Variable Interest Entities - As

Variable Interest Entities - Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Assets
Cash and cash equivalents	$ 285		$ 580
Short-term investments	0		17
Customers and agents, less allowances	919		908
Inventory, net	162		142
Other current assets	20		19
Assets held for sale	0		54
Licenses	2,471		2,186
Property, plant and equipment, net	2,207		2,202
Operating lease right-of-use assets	900	$ 899	0
Other assets and deferred charges	566	567	579
Liabilities
Current liabilities	750		691
Liabilities held for sale	0		1
Long-term operating lease liabilities	865	$ 878	0
Consolidated Variable Interest Entities
Assets
Cash and cash equivalents	19		9
Short-term investments	0		17
Customers and agents, less allowances	639		611
Inventory, net	6		5
Other current assets	7		6
Assets held for sale	0		4
Licenses	649		652
Property, plant and equipment, net	104		94
Operating lease right-of-use assets	44		0
Other assets and deferred charges	346		349
Total assets	1,814		1,747
Liabilities
Current liabilities	32		34
Liabilities held for sale	0		1
Long-term operating lease liabilities	41		0
Other deferred liabilities and credits	14		16
Total liabilities	$ 87		$ 51

Variable Interest Entities - Na

Variable Interest Entities - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Variable Interest Entities, Other Disclosures
Capital contributions, loans or advances	$ 255	$ 152	$ 821
King Street Wireless out of period adjustment
Variable Interest Entities, Other Disclosures
Immaterial error correction		During the first quarter of 2018, U.S. Cellular recorded an out-of-period adjustment attributable to 2016 and 2017 due to errors in the application of accounting guidance applicable to the calculation of Noncontrolling interests with redemption features related to King Street Wireless, Inc. This out-of-period adjustment had the impact of increasing Net income attributable to noncontrolling interests, net of tax, by $8 million and decreasing Net income attributable to U.S. Cellular shareholders by $8 million in 2018. U.S. Cellular determined that this adjustment was not material to any of the periods impacted.
Net income attributable to U.S. Cellular shareholders | King Street Wireless out of period adjustment
Variable Interest Entities, Other Disclosures
Out-of-period adjustment		$ (8)
Net income attributable to noncontrolling interests, net tax | King Street Wireless out of period adjustment
Variable Interest Entities, Other Disclosures
Out-of-period adjustment		8
Unconsolidated Variable Interest Entities
Variable Interest Entities, Other Disclosures
Investments in unconsolidated entities, maximum exposure	5	4
USCC EIP LLC
Variable Interest Entities, Other Disclosures
Capital contributions, loans or advances	$ 214	$ 116	$ 790

Noncontrolling Interests (Detai

Noncontrolling Interests (Details) $ in Millions	Dec. 31, 2019USD ($)
Noncontrolling Interest [Abstract]
Settlement value of mandatorily redeemable noncontrolling interests	$ 36
Carrying value of mandatorily redeemable noncontrolling interests	$ 15

Common Shareholders' Equity (De

Common Shareholders' Equity (Details)	Jan. 01, 2017shares	Nov. 30, 2009shares	Dec. 31, 2019voteshares	Dec. 31, 2018shares	Dec. 31, 2017shares
Series A Common Shares
Share repurchases
Number of votes | vote			10
Voting rights for number of board of directors			75%
Common Shares
Share repurchases
Number of votes | vote			1
Voting rights for number of board of directors			25%
Common Shares | 401(k)
Share repurchases
Shares reserved (in shares)			67,000
Common Shares | Treasury shares
Share repurchases
Repurchase authorization, cumulative shares authorized (in shares)			5,311,000
Common shareholders' equity, other disclosures
Shares reissued (in shares)			432,000	1,181,000	325,000
Common Shares | Treasury shares | Minimum
Share repurchases
Repurchase authorization, additional number of shares per year (in shares)	0
Common Shares | Treasury shares | Maximum
Share repurchases
Repurchase authorization, additional number of shares per year (in shares)	1,300,000	1,300,000

Stock-Based Compensation - Over

Stock-Based Compensation - Overview (Details) - U S Cellular - Common Shares	Dec. 31, 2019shares
Long-Term Incentive Plans
Stock-based compensation, overview
Shares reserved (in shares)	12,867,000
Non-Employee Directors' Plan
Stock-based compensation, overview
Shares reserved (in shares)	123,000

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock Options (Details) - Common Shares - Stock Options - Long-Term Incentive Plans - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	3 years
Stock compensation, stock option rollforward schedule, number of options
Outstanding, begin of period (in shares)	806,000
Exercisable options, beginning of period (in shares)	420,000
Exercised options (in shares)	(339,000)
Expired options (in shares)	(7,000)
Outstanding, end of period (in shares)	460,000	806,000
Exercisable options, ending of period (in shares)	460,000	420,000
Stock compensation, stock option rollforward schedule, other information
Options outstanding, begin of period - weighted average exercise price (USD per share)	$ 43.10
Options exercisable, begin of period - weighted average exercise price (USD per share)	42.39
Options exercised, weighted average exercise price (USD per share)	44.27
Options expired, weighted average exercise price (USD per share)	45.87
Options outstanding, end of period - weighted average exercise price (USD per share)	42.20	$ 43.10
Options exercisable, end of period - weighted average exercise price (USD per share)	$ 42.20	$ 42.39
Aggregate intrinsic value, options outstanding	$ 0
Aggregate intrinsic value, options exercisable	$ 0
Weighted average remaining contractual life, outstanding	4 years 10 months 24 days
Weighted average remaining contractual life, exercisable	4 years 10 months 24 days
Aggregate intrinsic value, options exercised	$ 3	$ 19	$ 1
Terminated Employees
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration period	30 days
Minimum | Retired Employees
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercisable term	90 days
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration period	10 years
Maximum | Retired Employees
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercisable term	1 year

Stock-Based Compensation - Rest

Stock-Based Compensation - Restricted Stock Units (Details) - Common Shares - Long-Term Incentive Plans - Restricted Stock Units - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	3 years
Stock based compensation, Nonvested shares rollforward, number of shares
Nonvested stock units, begin of period - Number of shares (in shares)	1,569,000
Granted number of shares (in shares)	478,000
Vested number of shares (in shares)	(525,000)
Forfeited number of shares (in shares)	(61,000)
Nonvested stock units, end of period - Number of shares (in shares)	1,461,000	1,569,000
Stock based compensation, Nonvested shares weighted average grant date fair value
Nonvested stock units - begin of period weighted average grant date fair value (USD per share)	$ 39.74
Granted weighted average grant date fair value (USD per share)	46.81	$ 38.19	$ 38.04
Vested weighted average grant date fair value (USD per share)	42.99
Forfeited weighted average grant date fair value (USD per share)	39.38
Nonvested stock units - end of period weighted average grant date fair value (USD per share)	$ 40.90	$ 39.74
Fair value of vested stock units	$ 25	$ 16	$ 11

Stock-Based Compensation - Perf

Stock-Based Compensation - Performance and Deferred Stock Units (Details) - Common Shares - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Long-Term Incentive Plans | Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	3 years
Stock based compensation, Nonvested shares rollforward, number of shares
Nonvested stock units, begin of period - Number of shares (in shares)	768,000
Granted number of shares (in shares)	323,000
Vested number of shares (in shares)	(5,000)
Change in units based on approved performance factors number of shares	188,000
Forfeited number of shares (in shares)	(29,000)
Nonvested stock units, end of period - Number of shares (in shares)	1,245,000	768,000
Stock based compensation, Nonvested shares weighted average grant date fair value
Nonvested stock units - begin of period weighted average grant date fair value (USD per share)	$ 37.78
Granted weighted average grant date fair value (USD per share)	46.43	$ 38.81	$ 36.92
Vested weighted average grant date fair value (USD per share)	37.92
Change in units based on approved performance factors weighted average grant date fair value	38.81
Forfeited weighted average grant date fair value (USD per share)	38.55
Nonvested stock units - end of period weighted average grant date fair value (USD per share)	$ 40.16	$ 37.78
Shares issued and granted under stock compensation plans
Fair value of vested stock units		$ 0	$ 0
Long-Term Incentive Plans | Performance Shares | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance share awards target	50.00%
Long-Term Incentive Plans | Performance Shares | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance share awards target	200.00%
Shares issued and granted under stock compensation plans
Fair value of vested stock units	$ 1,000,000
Long-Term Incentive Plans | Deferred Compensation Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	3 years
Stock based compensation, Nonvested shares weighted average grant date fair value
Granted weighted average grant date fair value (USD per share)	$ 0	$ 40.72	$ 36.02
Shares issued and granted under stock compensation plans
Percent of match up to 50% from annual bonus	25.00%
Percent of match above 50% from annual bonus	33.00%
Vested number of shares, unissued	34,000
Vested number of shares, unissued, fair value	$ 1,000,000
Long-Term Incentive Plans | Deferred Compensation Stock Units | Maximum
Shares issued and granted under stock compensation plans
Fair value of vested stock units	$ 1,000,000	$ 1,000,000	$ 1,000,000
U S Cellular | Non-Employee Directors' Plan
Shares issued and granted under stock compensation plans
Shares issued (in shares)	13,000	18,000	15,000

Stock-Based Compensation - Expe

Stock-Based Compensation - Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Stock based compensation expense
Total stock-based compensation expense, before income taxes	$ 41	$ 37	$ 30
Income tax benefit	(10)	(9)	(11)
Total stock-based compensation expense, net of income taxes	31	28	19
Unrecognized compensation cost for all stock-based compensation awards	$ 29
Weighted average period for recognition of unrecognized compensation cost for all stock-based compensation awards	1 year 9 months 18 days
Tax benefit from exercise of stock options and other awards	$ 7
Selling, general and administrative expense
Stock based compensation expense
Total stock-based compensation expense, before income taxes	36	33	27
System operations expense
Stock based compensation expense
Total stock-based compensation expense, before income taxes	5	4	3
Long-Term Incentive Plans | Stock Options
Stock based compensation expense
Total stock-based compensation expense, before income taxes	0	2	6
Long-Term Incentive Plans | Restricted Stock Units
Stock based compensation expense
Total stock-based compensation expense, before income taxes	22	21	19
Long-Term Incentive Plans | Performance Shares
Stock based compensation expense
Total stock-based compensation expense, before income taxes	18	13	4
Non-Employee Directors' Plan
Stock based compensation expense
Total stock-based compensation expense, before income taxes	$ 1	$ 1	$ 1

Supplemental Cash Flow Disclo_3

Supplemental Cash Flow Disclosures (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Supplemental Cash Flow [Line Items]
Interest paid	$ 107	$ 113	$ 111
Income taxes paid, net of refunds received	78	90	55
Cash receipts upon exercise of stock options	1	29	5
Cash disbursements for payment of taxes	(10)	(11)	(4)
Net cash receipts (disbursements) from exercise of stock options and vesting of other stock awards	$ (9)	$ 18	$ 1
Common Shares
Supplemental Cash Flow [Line Items]
Common Shares withheld (in shares)	452,000	1,550,000	145,000
Aggregate value of Common Shares withheld	$ 23	$ 73	$ 6

Certain Relationships and Rel_2

Certain Relationships and Related Transactions (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	May 04, 1988
Related Party Transaction [Line Items]
Billings to U.S. Cellular from TDS	$ 82	$ 86	$ 85
TDS | U.S. Cellular
Related Party Transaction [Line Items]
TDS ownership percentage	82.00%
TDS | U.S. Cellular | Minimum
Related Party Transaction [Line Items]
TDS ownership percentage				90.00%
Sidley Austin LLP
Related Party Transaction [Line Items]
Legal expense	$ 7	5	7
TDS
Related Party Transaction [Line Items]
Billings to U.S. Cellular from TDS	$ 82	$ 86	$ 85