Document and Entity Information - USD ($)	12 Months Ended
Document and Entity Information - USD ($)	Dec. 31, 2017	Mar. 09, 2018	Jun. 30, 2017
Document and Entity Information
Entity Registrant Name	QWEST CORP
Entity Central Index Key	0000068622
Document Type	10-K
Document Period End Date	Dec. 31, 2017
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Public Float			$ 0
Entity Common Stock, Shares Outstanding (shares)		1
Document Fiscal Year Focus	2017
Document Fiscal Period Focus	FY

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
OPERATING REVENUES
Operating revenues	$ 5,831	$ 6,247	$ 6,557
Operating revenues - affiliates	2,719	2,663	2,407
Total operating revenues	8,550	8,910	8,964
OPERATING EXPENSES
Cost of services and products (exclusive of depreciation and amortization)	2,881	2,934	2,872
Selling, general and administrative	925	1,020	1,015
Operating expenses - affiliates	848	941	960
Depreciation and amortization	1,583	1,691	1,857
Total operating expenses	6,237	6,586	6,704
OPERATING INCOME	2,313	2,324	2,260
OTHER (EXPENSE) INCOME
Interest expense	(465)	(478)	(473)
Interest expense - affiliates, net	(63)	(59)	(53)
Other income (expense), net	6	(24)	(1)
Total other expense, net	(522)	(561)	(527)
INCOME BEFORE INCOME TAX EXPENSE	1,791	1,763	1,733
Income tax expense	134	678	659
NET INCOME	$ 1,657	$ 1,085	$ 1,074

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
CURRENT ASSETS
Cash and cash equivalents	$ 1	$ 5
Accounts receivable, less allowance of $47 and $53	646	700
Advances to affiliates	1,024	872
Other	98	129
Total current assets	1,769	1,706
NET PROPERTY, PLANT AND EQUIPMENT
Property, plant and equipment	14,316	13,247
Accumulated depreciation	(6,392)	(5,602)
Net property, plant and equipment	7,924	7,645
GOODWILL AND OTHER ASSETS
Goodwill	9,360	9,354
Other intangible assets, net	379	471
Other, net	75	96
Total goodwill and other assets	11,176	11,798
TOTAL ASSETS	20,869	21,149
CURRENT LIABILITIES
Current maturities of long-term debt	17	514
Accounts payable	317	398
Note payable - affiliate	965	914
Accrued expenses and other liabilities
Salaries and benefits	238	273
Income and other taxes	174	175
Other	138	122
Current affiliate obligations, net	82	87
Advance billings and customer deposits	265	313
Total current liabilities	2,196	2,796
LONG-TERM DEBT	7,264	6,747
DEFERRED CREDITS AND OTHER LIABILITIES
Deferred revenues	128	131
Deferred income taxes, net	1,001	1,773
Affiliate obligations, net	861	944
Other	82	66
Total deferred credits and other liabilities	2,072	2,914
COMMITMENTS AND CONTINGENCIES (Note 15)
STOCKHOLDER'S EQUITY
Common stock - one share without par value, owned by Qwest Services Corporation	10,050	10,050
Accumulated deficit	(713)	(1,358)
Total stockholder's equity	9,337	8,692
TOTAL LIABILITIES AND STOCKHOLDER'S EQUITY	20,869	21,149
Customer Relationships
Customer relationships, net	$ 1,362	$ 1,877

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Accounts receivable, allowance (in dollars)	$ 47	$ 53
Common stock, shares outstanding (in shares)	1	1
Common stock, shares issued (in shares)	1	1
Common stock, value outstanding	$ 10,050	$ 10,050

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
OPERATING ACTIVITIES
Net income	$ 1,657	$ 1,085	$ 1,074
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	1,583	1,691	1,857
Deferred income taxes	(773)	(123)	(189)
Provision for uncollectible accounts	74	80	78
Net long-term debt issuance costs and premium amortization	(2)	(12)	(18)
Accrued interest on affiliate note	51	59	59
Net loss on early retirement of debt	5	27	0
Impairment of asset	1	11	0
Changes in current assets and liabilities:
Accounts receivable	(20)	(92)	(26)
Accounts payable	(44)	5	(79)
Accrued income and other taxes	(1)	(14)	(8)
Other current assets and liabilities, net	(36)	47	1
Other current assets and liabilities - affiliates	11	0	(4)
Changes in other noncurrent assets and liabilities, net	17	1	(30)
Changes in affiliate obligations, net	(88)	(117)	(123)
Other, net	0	4	(1)
Net cash provided by operating activities	2,435	2,652	2,591
INVESTING ACTIVITIES
Payments for property, plant and equipment and capitalized software	(1,328)	(1,259)	(1,247)
Changes in advances to affiliates	(152)	(84)	24
Proceeds from sale of property	49	9	3
Cash paid for acquisition	(5)	0	0
Net cash used in investing activities	(1,436)	(1,334)	(1,220)
FINANCING ACTIVITIES
Net proceeds from issuance of long-term debt	638	1,173	495
Payments of long-term debt	(641)	(1,189)	(517)
Early retirement of debt costs	0	0	(2)
Dividends paid to Qwest Services Corporation	(1,000)	(1,300)	(1,350)
Net cash used in financing activities	(1,003)	(1,316)	(1,374)
Net (decrease) increase in cash and cash equivalents	(4)	2	(3)
Cash and cash equivalents at beginning of period	5	3	6
Cash and cash equivalents at end of period	1	5	3
Supplemental cash flow information:
Income taxes paid, net	(907)	(801)	(848)
Interest paid (net of capitalized interest of $32, $19 and $18)	$ (467)	$ (488)	$ (497)

CONSOLIDATED STATEMENTS OF CASH FLOWS (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Cash Flows [Abstract]
Interest paid, capitalized interest	$ 32	$ 19	$ 18

CONSOLIDATED STATEMENTS OF STOCKHOLDER'S EQUITY (DEFICIT) - USD ($) $ in Millions	Total	COMMON STOCK	ACCUMULATED DEFICIT
Balance at beginning of period at Dec. 31, 2014		$ 10,050	$ (867)
Increase (Decrease) in Stockholder's Equity
Net income	$ 1,074		1,074
Dividends declared to Qwest Services Corporation	(1,350)		(1,350)
Dividend of equity interest in limited liability company to Qwest Services Corporation			0
Balance at end of period at Dec. 31, 2015	8,907	10,050	(1,143)
Increase (Decrease) in Stockholder's Equity
Net income	1,085		1,085
Dividends declared to Qwest Services Corporation	(1,300)		(1,300)
Dividend of equity interest in limited liability company to Qwest Services Corporation			0
Balance at end of period at Dec. 31, 2016	8,692	10,050	(1,358)
Increase (Decrease) in Stockholder's Equity
Net income	1,657		1,657
Dividends declared to Qwest Services Corporation	(1,000)		(1,000)
Dividend of equity interest in limited liability company to Qwest Services Corporation			(12)
Balance at end of period at Dec. 31, 2017	$ 9,337	$ 10,050	$ (713)

Basis of Presentation and Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Basis of Presentation and Summary of SIgnificant Accounting Policies	Background and Summary of Significant Accounting Policies General We are an integrated communications company engaged primarily in providing an array of communications services to our business and residential customers. Our communications services include local voice, broadband, private line (including business data services), Ethernet, network access, information technology and other ancillary services. In certain local and regional markets, we also provide local access and fiber transport services to competitive local exchange carriers. We generate the majority of our total consolidated operating revenues from services provided in the 14-state region of Arizona, Colorado, Idaho, Iowa, Minnesota, Montana, Nebraska, New Mexico, North Dakota, Oregon, South Dakota, Utah, Washington and Wyoming. We refer to this region as our local service area. On April 1, 2011, our indirect parent QCII became a wholly-owned subsidiary of CenturyLink, Inc. in a tax-free, stock-for-stock transaction. Basis of Presentation The accompanying consolidated financial statements include our accounts and the accounts of our subsidiaries. Intercompany amounts and transactions with our consolidated subsidiaries have been eliminated. Transactions with our non-consolidated affiliates (referred to herein as affiliates) have not been eliminated. We reclassified certain prior period amounts to conform to the current period presentation, including the categorization of our revenues for 2016 and 2015. See Note 9—Products and Services Revenues for additional information. These changes had no impact on total operating revenues, total operating expenses or net income for any period presented. Summary of Significant Accounting Policies Use of Estimates Our consolidated financial statements are prepared in accordance with U.S. generally accepted accounting principles. These accounting principles require us to make certain estimates, judgments and assumptions. We believe that the estimates, judgments and assumptions we make when accounting for specific items and matters, including, but not limited to, long-term contracts, customer retention patterns, allowance for doubtful accounts, depreciation, amortization, asset valuations, rates used for affiliate cost allocations, internal labor capitalization rates, recoverability of assets (including deferred tax assets), impairment assessments, taxes, certain liabilities and other provisions and contingencies, are reasonable, based on information available at the time they are made. Our accounting for CenturyLink's indirect acquisition of us required extensive use of estimates in determining the acquisition date fair values of our assets and liabilities. These estimates, judgments and assumptions can materially affect the reported amounts of assets, liabilities and components of stockholder's equity as of the dates of the consolidated balance sheets, as well as the reported amounts of revenues, expenses and components of cash flows during the periods presented in our other consolidated financial statements. We also make estimates in our assessments of potential losses in relation to threatened or pending tax and legal matters. See Note 11—Income Taxes and Note 15—Commitments and Contingencies for additional information. For matters not related to income taxes, if a loss is considered probable and the amount can be reasonably estimated, we recognize an expense for the estimated loss. If we have the potential to recover a portion of the estimated loss from a third party, we make a separate assessment of recoverability and reduce the estimated loss if recovery is also deemed probable. For matters related to income taxes, if we determine that the impact of an uncertain tax position is more likely than not to be sustained upon audit by the relevant taxing authority, then we recognize a benefit for the largest amount that is more likely than not to be sustained. No portion of an uncertain tax position will be recognized if the position has less than a 50% likelihood of being sustained. Interest is recognized on the amount of unrecognized benefit from uncertain tax positions. For all of these and other matters, actual results could differ materially from our estimates. Revenue Recognition We recognize revenue for services when the related services are provided. Recognition of certain payments received in advance of services being provided is deferred until the service is provided. These advance payments include activation and installation charges, which we recognize as revenue over the expected customer relationship period, which ranges from three to seven years depending on the service. We also defer costs for customer activations and installations. The deferral of customer activation and installation costs is limited to the amount of revenue deferred on advance payments. Costs in excess of advance payments are recorded as expense in the period such costs are incurred. Expected customer relationship periods are estimated using historical experience. In most cases, termination fees or other fees on existing contracts that are negotiated in conjunction with new contracts are deferred and recognized over the new contract term. We offer bundle discounts to our customers who receive certain groupings of services. These bundle discounts are recognized concurrently with the associated revenue and are allocated to the various services in the bundled offering based on the estimated selling price of services included in each bundled combination. Customer arrangements that include both equipment and services are evaluated to determine whether the elements are separable. If the elements are deemed separable and separate earnings processes exist, the revenue associated with the customer arrangement is allocated to each element based on the relative estimated selling price of the separate elements. We have estimated the selling prices of each element by reference to vendor-specific objective evidence of selling prices when the elements are sold separately. The revenue associated with each element is then recognized as earned. For example, if we receive an advance payment when we sell equipment and continuing service together, we immediately recognize as revenue the amount allocated to the equipment as long as all the conditions for revenue recognition have been satisfied. The portion of the advance payment allocated to the service based upon its relative selling price is recognized ratably over the longer of the contractual period or the expected customer relationship period. In connection with offering products and services provided by third-party vendors, we review the relationship between us, the vendor and the end customer to assess whether revenue should be reported on a gross or net basis. In assessing whether revenue should be reported on a gross or net basis, we consider whether we act as a principal in the transaction, take title to the products, have risk and rewards of ownership or act as an agent or broker. Affiliate Transactions We provide to our affiliates telecommunications services that we also provide to external customers. In addition, we provide to our affiliates computer system development and support services. Services provided by us to our affiliates are recognized as operating revenue-affiliates in our consolidated statements of operations. We also purchase services from our affiliates including telecommunications services, marketing and employee-related support services. Services provided to us from our affiliates are recognized as operating expenses-affiliates on our consolidated statements of operations. Because of the significance of the services we provide to our affiliates and our affiliates provide to us, the results of operations, financial position and cash flows presented herein are not necessarily indicative of the results of operations, financial position and cash flows we would have achieved had we operated as a stand-alone entity during the periods presented. We recognize intercompany charges at the amounts billed to us by our affiliates and we recognize intercompany revenue for services we bill to our affiliates. Regulatory rules require certain revenues and expenses to be recorded at market price or fully distributed cost. Our compliance with regulations is subject to review by regulators. Adjustments to intercompany charges that result from these reviews are recorded in the period they become known. CenturyLink has cash management arrangements between certain of its subsidiaries that include lines of credit, affiliate obligations, capital contributions and dividends. As part of these cash management arrangements, an affiliate provides lines of credit to certain other affiliates. Amounts outstanding under these lines of credit and intercompany obligations vary from time to time. Under these arrangements, the majority of our cash balance is transferred on a daily basis to CenturyLink and most affiliate transactions are deemed to be settled at the time the transactions are recorded in our accounting records, with the resulting net balance at the end of each period reflected as advances to affiliates on the accompanying consolidated balance sheets. From time to time we declare and pay dividends to our parent, QSC, which are settled through the advances to affiliates, which has the net effect of reducing the amount of these advances. Dividends declared are reflected on our consolidated statements of stockholder's equity and the consolidated statements of cash flows reflects the changes in advances to affiliates as investing activities and changes in advances from affiliates as financing activities. Interest is assessed on the advances to/from affiliates on either the three-month U.S T-bill rate (for advances to affiliates) or CenturyLink’s weighted average borrowing rate (for advances from affiliates). The affiliate obligations, net in current and noncurrent liabilities on our consolidated balance sheets primarily represents the cumulative allocation of expense, net of payments, associated with QCII’s pension plans and post-retirement benefits plans prior to the plan mergers. In 2015, we agreed to a plan to settle the outstanding affiliate obligations, net balance with QCII over a 30 year term. Under the plan, payments are scheduled to be made on a monthly basis. For the years ended December 31, 2017 and 2016, we made settlement payments of $87 million and $97 million, respectively, to QCII in accordance with plan. Changes in the affiliate obligations, net are reflected in operating activities on our consolidated statements of cash flows. In the normal course of business, we transfer assets to and from various affiliates through our parent, QSC, which are recorded through our equity. It is our policy to record asset transfers based on carrying values. USF Surcharges, Gross Receipts Taxes and Other Surcharges In determining whether to include in our revenues and expenses the taxes and surcharges collected from customers and remitted to government authorities, including USF surcharges, sales, use, value added and some excise taxes, we assess, among other things, whether we are the primary obligor or principal taxpayer for the taxes assessed in each jurisdiction where we do business. In jurisdictions where we determine that we are the principal taxpayer, we record the surcharges on a gross basis and include them in our revenues and costs of services and products. In jurisdictions where we determine that we are merely a collection agent for the government authority, we record the taxes on a net basis and do not include them in our revenues and costs of services and products. Advertising Costs Costs related to advertising are expensed as incurred and included in selling, general and administrative expenses in our consolidated statements of operations. Our advertising expense was $139 million, $91 million and $84 million for the years ended December 31, 2017, 2016 and 2015, respectively. Legal Costs In the normal course of our business, we incur costs to hire and retain external legal counsel to advise us on regulatory, litigation and other matters. We expense these costs as the related services are received. Income Taxes Our results are included in the CenturyLink consolidated federal income tax return and certain combined state income tax returns. CenturyLink allocates income tax expense to us based upon a separate return allocation method which results in income tax expense that approximates the expense that would result if we were a stand-alone entity. Our reported deferred tax assets and liabilities, as discussed below and in Note 11—Income Taxes, are primarily determined as a result of the application of the separate return allocation method and therefore the settlement of these amounts is dependent upon our parent, CenturyLink, rather than tax authorities. Our current expectation is that the vast majority of deferred tax assets and liabilities will be settled through our general intercompany obligation based upon the current CenturyLink policy. CenturyLink has the right to change their policy regarding settlement of these assets and liabilities at any time. The provision for income taxes consists of an amount for taxes currently payable, an amount for tax consequences deferred to future periods and adjustments to our liabilities for uncertain tax positions. We record deferred income tax assets and liabilities reflecting future tax consequences attributable to differences between the financial statement carrying value of assets and liabilities and the tax bases of those assets and liabilities. Deferred taxes are computed using enacted tax rates expected to apply in the year in which the differences are expected to affect taxable income. The effect on deferred income tax assets and liabilities of a change in tax rate is recognized in earnings in the period that includes the enactment date. We establish valuation allowances when necessary to reduce deferred income tax assets to the amounts that we believe are more likely than not to be recovered. Each quarter we evaluate the need to retain all or a portion of the valuation allowance on our deferred tax assets. See Note 11—Income Taxes for additional information. Cash and Cash Equivalents Cash and cash equivalents include highly liquid investments that are readily convertible into cash and are not subject to significant risk from fluctuations in interest rates. As a result, the value at which cash and cash equivalents are reported in our consolidated financial statements approximates their fair value. Our cash collections are transferred to CenturyLink on a daily basis and our ultimate parent funds our cash disbursement needs. The net cash transferred to CenturyLink has been reflected as advances to affiliates in our consolidated balance sheets. Accounts Receivable and Allowance for Doubtful Accounts Accounts receivable are recognized based upon the amount due from customers for the services provided or at cost for purchased and other receivables less an allowance for doubtful accounts. The allowance for doubtful accounts receivable reflects our best estimate of probable losses inherent in our receivable portfolio determined on the basis of historical experience, specific allowances for known troubled accounts and other currently available evidence. We generally consider our accounts past due if they are outstanding over 30 days. Our collection process varies by the customer segment, amount of the receivable, and our evaluation of the customer's credit risk. Our past due accounts are written off against our allowance for doubtful accounts when collection is considered to be not probable. Any recoveries of accounts previously written off are generally recognized as a reduction in bad debt expense in the period received. The carrying value of accounts receivable, net of the allowance for doubtful accounts, approximates fair value. Property, Plant and Equipment As a result of our indirect acquisition by CenturyLink, property, plant and equipment acquired at the time of acquisition was recorded based on its estimated fair value as of the acquisition date. Subsequently purchased and constructed property, plant and equipment are recorded at cost. Property, plant and equipment is depreciated primarily using the straight-line group method. Under the straight-line group method, assets dedicated to providing telecommunications services (which comprise the majority of our property, plant and equipment) that have similar physical characteristics, use and expected useful lives are pooled for purposes of depreciation and tracking. The equal life group procedure is used to establish each pool's average remaining useful life. Generally, under the straight-line group method, when an asset is sold or retired in the course of normal business activities, the cost is deducted from property, plant and equipment and charged to accumulated depreciation without recognition of a gain or loss. A gain or loss is recognized in our consolidated statements of operations only if a disposal is unusual. Leasehold improvements are amortized over the shorter of the useful lives of the assets or the expected lease term. Expenditures for maintenance and repairs are expensed as incurred. Interest is capitalized during the construction phase of network and other internal-use capital projects. Employee-related costs for construction of network and other internal use assets are also capitalized during the construction phase. Property, plant and equipment supplies used internally are carried at average cost, except for significant individual items for which cost is based on specific identification. We perform annual internal reviews to evaluate the reasonableness of the depreciable lives for our property, plant and equipment. Our reviews utilize models that take into account actual usage, physical wear and tear, replacement history, assumptions about technology evolution and, in certain instances, actuarially determined probabilities to estimate the remaining useful life of our asset base. Our remaining useful life assessments anticipate the loss in service value of assets that may precede the physical retirement. Assets shared among many customers may lose service value as those customers leave the network. However, the asset is not retired until all customers no longer utilize the asset and we determine there is no alternative use for the asset. We review long-lived tangible assets for impairment whenever facts and circumstances indicate that the carrying amounts of the assets may not be recoverable. For assessment purposes, long-lived assets are grouped with other assets and liabilities at the lowest level for which identifiable cash flows are largely independent of the cash flows of other assets and liabilities, absent a material change in operations. An impairment loss is recognized only if the carrying amount of the asset group is not recoverable and exceeds its fair value. Recoverability of the asset group to be held and used is assessed by comparing the carrying amount of the asset group to the estimated undiscounted future net cash flows expected to be generated by the asset group. If the asset group's carrying value is not recoverable, an impairment charge is recognized for the amount by which the carrying amount of the asset group exceeds its fair value. We determine fair values by using a combination of comparable market values and discounted cash flows, as appropriate. Goodwill, Customer Relationships and Other Intangible Assets Intangible assets arising from business combinations, such as goodwill, customer relationships and capitalized software are initially recorded at estimated fair value. We amortize customer relationships primarily over an estimated life of ten years, using either the sum-of-the-years-digits or the straight-line methods, depending on the type of customer. We amortize capitalized software using the straight-line method over estimated lives ranging up to seven years. Other intangible assets not arising from business combinations are initially recorded at cost. Internally used software, whether purchased or developed by us, is capitalized and amortized using the straight-line method over its estimated useful life. We have capitalized certain costs associated with software such as costs of employees devoting time to the projects and external direct costs for materials and services. Costs associated with software to be used for internal purposes are expensed until the point at which the project has reached the development stage. Subsequent additions, modifications or upgrades to internal-use software are capitalized only to the extent that they allow the software to perform a task it previously did not perform. Software maintenance, data conversion and training costs are expensed in the period in which they are incurred. We review the remaining economic lives of our capitalized software annually. Capitalized software is included in other intangible assets, net, in our consolidated balance sheets. We are required to assess goodwill for impairment at least annually, or more frequently, if an event occurs or circumstances change that would indicate an impairment may have occurred. We are required to write-down the value of goodwill in periods in which the recorded amount of goodwill exceeds the implied fair value of goodwill. The impairment assessment is performed annually at the reporting unit level. We have determined that our operations consist of one reporting unit, consistent with our determination that our business consists of one operating segment. See Note 2—Goodwill, Customer Relationships and Other Intangible Assets for additional information. Pension and Post-Retirement Benefits A substantial portion of our active and retired employees participate in the CenturyLink Combined Pension Plan. On December 31, 2014, the QCII pension plan and a pension plan of an affiliate were merged into the CenturyLink Retirement Plan. The CenturyLink Retirement Plan was renamed the CenturyLink Combined Pension Plan. Prior to the pension plan merger, the above-noted employees participated in the QCII pension plan. In addition, certain of our employees participate in CenturyLink's post-retirement health care and life insurance benefit plans. CenturyLink allocates service costs relating to pension and post-retirement health care and life insurance benefits to us and its other affiliates. The amounts contributed by us through CenturyLink are not segregated or restricted to pay amounts due to our employees and may be used to provide benefits to other employees of CenturyLink. The allocation of the service costs to us is based upon our employees who are currently earning benefits under the plans. For further information on qualified pension, post-retirement and other post-employment benefit plans, see CenturyLink's annual report on Form 10-K for the year ended December 31, 2017. Recent Accounting Pronouncements Goodwill Impairment On January 26, 2017, The Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update ("ASU") ASU 2017-04, “Simplifying the Test for Goodwill Impairment” (“ASU 2017-04”). ASU 2017-04 simplifies the impairment testing for goodwill by changing the measurement for goodwill impairment. Under current rules, we are required to compute the implied fair value of goodwill to measure the impairment amount if the carrying value of a reporting unit exceeds its fair value. Under ASU 2017-04, the goodwill impairment charge will equal the excess of the reporting unit carrying value above fair value, limited to the amount of goodwill assigned to the reporting unit. We are required to adopt the provisions of ASU 2017-04 for any goodwill impairment tests, including our required annual test, occurring after January 1, 2020, but have the option to early adopt for any impairment test that we are required to perform. We have not determined if we will elect to early adopt the provisions of ASU 2017-04. The provisions of ASU 2017-04 would not have affected our last goodwill impairment assessment, but no assurance can be provided that the simplified testing methodology will not affect our goodwill impairment assessment in the future. Income Taxes On October 24, 2016, the FASB issued ASU 2016-16, “Intra-Entity Transfers of Assets Other Than Inventory” ("ASU 2016-16"). ASU 2016-16 eliminates the current prohibition on the recognition of the income tax effects on the transfer of assets among our subsidiaries. After adoption of this ASU, the income tax effects associated with these asset transfers, except for the transfer of inventory, will be recognized in the period the asset is transferred versus the current deferral and recognition upon either the sale of the asset to a third party or over the remaining useful life of the asset. We plan to adopt the provisions of ASU 2016-16 on January 1, 2018. The adoption of ASU 2016-16 is not expected to have a material impact to our consolidated financial statements. Financial Instruments On June 16, 2016, the FASB issued ASU 2016-13, “Measurement of Credit Losses on Financial Instruments” (“ASU 2016-13”). The primary impact of ASU 2016-13 for us is a change in the model for the recognition of credit losses related to our financial instruments from an incurred loss model, which recognized credit losses only if it was probable that a loss had been incurred, to an expected loss model, which requires our management team to estimate the total credit losses expected on the portfolio of financial instruments. We are currently reviewing the requirements of the standard and evaluating the impact on our consolidated financial statements. We are required to adopt the provisions of ASU 2016-13 effective January 1, 2020, but could elect to early adopt the provisions as of January 1, 2019. We expect to recognize the impacts of adopting ASU 2016-13 through a cumulative adjustment to retained earnings as of the date of adoption. As of the date of this report, we have not yet determined the date we will adopt ASU 2016-13. Leases On February 25, 2016, the FASB issued ASU 2016-02, “Leases” (“ASU 2016-02”). The core principle of ASU 2016-02 will require lessees to present right-of-use assets and lease liabilities on their balance sheets for operating leases, which are currently not reflected on their balance sheets. ASU 2016-02 is effective for annual and interim periods beginning January 1, 2019. Early adoption of ASU 2016-02 is permitted. Upon adoption of ASU 2016-02, we are required to recognize and measure leases at the beginning of the earliest period presented in our consolidated financial statements using a modified retrospective approach. The modified retrospective approach includes a number of optional practical expedients that we may elect to apply. We have completed our initial assessment of our business and system requirements and we are currently developing and implementing a new lease accounting and administrative system to comply with the requirements of ASU 2016-02. We plan to adopt the standard when it becomes effective for us beginning January 1, 2019 and the adoption of the standard will result in the recognition of right of use assets and lease liabilities that have not previously been recorded. Although we believe it is premature as of the date of this report to provide any estimate of the impact of adopting ASU 2016-02, we do expect that it will have a material impact on our consolidated financial statements. Revenue Recognition On May 28, 2014, the FASB issued ASU 2014-09, “Revenue from Contracts with Customers” (“ASU 2014-09”). ASU 2014-09 replaces virtually all existing generally accepted accounting principles (“GAAP”) on revenue recognition and replaces them with a principles-based approach for determining revenue recognition using a new five step model. The core principle of ASU 2014-09 is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. ASU 2014-09 also includes new accounting principles related to the deferral and amortization of contract acquisition and fulfillment costs. On July 9, 2015, the FASB approved the deferral of the effective date of ASU 2014-09 by one year until January 1, 2018, which is the date we plan to adopt this standard. ASU 2014-09 may be adopted by applying the provisions of this standard on a retrospective basis to the periods included in the financial statements or on a modified retrospective basis which would result in the recognition of a cumulative effect of adopting ASU 2014-09 in the first quarter of 2018. We plan to adopt the new revenue recognition standard under the modified retrospective transition method. The most significant judgments and impacts upon adoption of the standard include the following items: Upon adoption, we will defer (i.e. capitalize) incremental contract acquisition costs and recognize (i.e. amortize) them over the term of the initial contract and anticipated renewal contracts to which the costs relate. Our deferred contract costs for our business and consumer customers have average amortization periods of approximately 49 months and 30 months, respectively, and are subject to being monitored every period to reflect any significant change in assumptions. In addition, we will assess our deferred contract cost asset for impairment on a periodic basis. Promotional bill credits, discounts and prepaid cards offered to customers as part of renewing services or entering into a new services arrangement that are paid over time and are contingent on the customer maintaining a service contract results in an extended service contract term with multiple performance obligations, which impacts the allocation and timing of revenue recognition between service revenue and revenue assigned to the customer credits. A contract asset will be recorded when services are delivered to the customer, and subsequently recognized as a reduction to service revenue over the extended contract term. We are in the process of implementing a new revenue accounting system, as well as, new processes and internal controls over revenue recognition to assist us in the application of the new standard. The cumulative effect of initially applying the new revenue standard on January 1, 2018 is estimated to be an increase to retained earnings of approximately $150 million to $300 million.

Goodwill, Customer Relationships and Other Intangible Assets

12 Months Ended

Dec. 31, 2017

Goodwill and Intangible Assets Disclosure [Abstract]

Goodwill, Customer Relationships and Other Intangible Assets

Goodwill, customer relationships and other intangible assets consisted of the following:



	As of December 31,
	2017		2016
	(Dollars in millions)
Goodwill	$	9,360	9,354
Customer relationships, less accumulated amortization of $4,337 and $3,822	$	1,362	1,877
Other intangible assets subject to amortization:
Capitalized software, less accumulated amortization of $1,619 and $1,510	$	379	471

As of December 31, 2017, the gross carrying amount of goodwill, customer relationships and other intangible assets was $17.057 billion.

Total amortization expense for intangible assets was as follows:



	Years Ended December 31,
	2017		2016	2015
	(Dollars in millions)
Amortization expense for intangible assets	$	671	767	871

We estimate that total amortization expense for intangible assets for the years ending December 31, 2018 through 2022 will be as follows:



	(Dollars in millions)
Year ending December 31,
2018	$	583
2019	513
2020	446
2021	136
2022	32

We annually review the estimated lives and methods used to amortize our other intangible assets. The actual amounts of amortization expense may differ materially from our estimates, depending on the results of our annual reviews.

Substantially, all of our goodwill was derived from CenturyLink's acquisition of us where the purchase price exceeded the fair value of the net assets acquired.

We assess our goodwill for impairment annually, or, under certain circumstances, more frequently, such as when events or changes in circumstances indicate there may be impairment. We are required to write down the value of goodwill only when our assessment determines the recorded amount of goodwill exceeds the implied fair value. Our annual impairment assessment date for goodwill is October 31, at which date we assessed goodwill at our reporting units. In reviewing the criteria for reporting units, we have determined that we are one reporting unit.

We compare our estimated fair value of equity to our carrying value of equity. If the estimated fair value of our equity is greater than the carrying value of our equity, we conclude that no impairment exists. If the estimated fair value of our equity is less than our carrying value of our equity, a second calculation is required in which the implied fair value of goodwill is compared to our carrying value of goodwill. If the implied fair value of goodwill is less than our carrying value of goodwill, goodwill must be written down to the implied fair value.

At October 31, 2017, we utilized a Level 3 valuation technique to estimate the fair value of our equity by considering both a market approach and a discounted cash flow method. The market approach method includes the use of comparable multiples of publicly traded companies whose services are comparable to ours. The discounted cash flow method is based on the present value of projected cash flows and a terminal value, which represents the expected normalized cash flows of the reporting unit beyond the cash flows from the discrete projection period. Based on our assessment performed with respect to our reporting unit as described above, we concluded that our goodwill was not impaired as of that date. As of October 31, 2016 and 2015, based on our assessments performed, we concluded that our goodwill was not impaired as of those dates.

- Definition

The entire disclosure for the aggregate amount of goodwill and a description of intangible assets, which may include (a) for amortizable intangible assets (also referred to as finite-lived intangible assets), the carrying amount, the amount of any significant residual value, and the weighted-average amortization period, (b) for intangible assets not subject to amortization (also referred to as indefinite-lived intangible assets), the carrying amount, and (c) the amount of research and development assets acquired and written off in the period, including the line item in the income statement in which the amounts written off are aggregated, if not readily apparent from the income statement. Also discloses (a) for amortizable intangibles assets in total and by major class, the gross carrying amount and accumulated amortization, the total amortization expense for the period, and the estimated aggregate amortization expense for each of the five succeeding fiscal years, (b) for intangible assets not subject to amortization the carrying amount in total and by major class, and (c) for goodwill, in total and for each reportable segment, the changes in the carrying amount of goodwill during the period (including the aggregate amount of goodwill acquired, the aggregate amount of impairment losses recognized, and the amount of goodwill included in the gain (loss) on disposal of a reporting unit). If any part of goodwill has not been allocated to a reportable segment, discloses the unallocated amount and the reasons for not allocating. For each impairment loss recognized related to an intangible asset (excluding goodwill), discloses: (a) a description of the impaired intangible asset and the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method for determining fair value, (c) the caption in the income statement or the statement of activities in which the impairment loss is aggregated, and (d) the segment in which the impaired intangible asset is reported. For each goodwill impairment loss recognized, discloses: (a) a description of the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method of determining the fair value of the associated reporting unit, and (c) if a recognized impairment loss is an estimate not finalized and the reasons why the estimate is not final. May also disclose the nature and amount of any significant adjustments made to a previous estimate of an impairment loss.

+ References + Details

Long-Term Debt and Revolving Promissory Note

12 Months Ended

Dec. 31, 2017

Debt Disclosure [Abstract]

Long-Term Debt and Revolving Promissory Note

Long-term debt, including unamortized premiums and discounts, unamortized debt issuance costs and note payable-affiliate, were as follows:



			As of December 31,
	Interest Rates	Maturities	2017			2016
			(Dollars in millions)
Senior notes	6.125% - 7.750%	2021 - 2057	$	7,294		7,259
Term loan	3.570%	2025	100			100
Capital lease and other obligations	Various	Various	36			32
Unamortized premiums, net			1			4
Unamortized debt issuance costs			(150		)	(134	)
Total long-term debt			7,281			7,261
Less current maturities			(17		)	(514	)
Long-term debt, excluding current maturities			$	7,264		6,747
Note payable-affiliate	6.710%	2022	$	965		914

New Issuances

2017

On April 27, 2017, Qwest Corporation issued $575 million aggregate principal amount of 6.75% Notes due 2057 and, on May 5, 2017, issued an additional $85 million aggregate principal amount of such notes pursuant to an over-allotment option in exchange for aggregate net proceeds, after deducting underwriting discounts and other expenses, of $638 million. All of the 6.75% Notes are senior unsecured obligations and may be redeemed by Qwest Corporation, in whole or in part, on or after June 15, 2022, at a redemption price equal to 100% of the principal amount redeemed plus accrued and unpaid interest to the redemption date.

2016

On August 22, 2016, Qwest Corporation issued $978 million aggregate principal amount of 6.5% Notes due 2056, including $128 million principal amount that was sold pursuant to an over-allotment option, in exchange for net proceeds, after deducting underwriting discounts and other expenses, of $946 million. All of the 6.5% Notes are unsecured obligations and may be redeemed by Qwest Corporation, in whole or in part, on or after September 1, 2021, at a redemption price equal to 100% of the principal amount redeemed plus accrued and unpaid interest to the redemption date.

On January 29, 2016, Qwest Corporation issued $235 million aggregate principal amount of 7% Notes due 2056, in exchange for net proceeds, after deducting underwriting discounts and other expenses, of $227 million. All of the 7% Notes are unsecured obligations and may be redeemed by Qwest Corporation, in whole or in part, on or after February 1, 2021, at a redemption price equal to 100% of the principal amount redeemed plus accrued and unpaid interest to the redemption date.

Repayments

2017

On May 9, 2017, Qwest Corporation redeemed $125 million aggregate principal amount of the remaining $288 million of its 7.5% Notes due 2051, which resulted in an immaterial loss.

On May 4, 2017, Qwest Corporation redeemed all $500 million of its 6.5% Notes due 2017, which resulted in an immaterial loss.

2016

On September 15, 2016, Qwest Corporation redeemed $287 million of its 7.5% Notes due 2051, which resulted in a loss of $9 million.

On August 29, 2016, Qwest Corporation redeemed all $661 million of its 7.375% Notes due 2051, which resulted in a loss of $18 million.

On May 2, 2016, Qwest Corporation paid at maturity the $235 million principal amount and accrued and unpaid interest due under its 8.375% Notes.

Term Loan

In 2015, Qwest Corporation entered into a term loan in the amount of $100 million with CoBank, ACB. The outstanding unpaid principal amount of this term loan plus any accrued and unpaid interest is due on February 20, 2025. Interest is paid monthly based upon either the applicable London Interbank Offered Rate (“LIBOR”) or the base rate (as defined in the credit agreement) plus an applicable margin between 1.50% to 2.50% per annum for LIBOR loans and 0.50% to 1.50% per annum for base rate loans depending on Qwest Corporation's then current senior unsecured long-term debt rating. At both December 31, 2017 and 2016, the outstanding principal balance on this term loan was $100 million.

Aggregate Maturities of Long-Term Debt

Set forth below is the aggregate principal amount of our long-term debt (excluding unamortized premiums and discounts and unamortized debt issuance costs and other and excluding note payable-affiliate) maturing during the following years:



	(Dollars in millions)⁽¹⁾
2018	$	17
2019	10
2020	5
2021	951
2022	1
2023 and thereafter	6,446
Total long-term debt	$	7,430

_______________________________________________________________________________

⁽¹⁾Actual principal paid in any year may differ due to the possible future refinancing of outstanding debt or the issuance of new debt.

Revolving Promissory Note

On September 30, 2017, Qwest Corporation entered into an amended and restated revolving promissory note in the amount of $965 million with an affiliate of our ultimate parent company, CenturyLink, Inc. This note replaced and amended the original $1.0 billion revolving promissory note Qwest Corporation entered into on April 18, 2012 with the same affiliate. The outstanding principal balance of this new revolving promissory note and the accrued interest thereon shall be due and payable on demand, but if no demand is made, then on June 30, 2022. Interest is accrued on the outstanding balance during an interest period using a weighted average per annum interest rate on the consolidated outstanding debt of CenturyLink and its subsidiaries. As of December 31, 2017, the amended and restated revolving promissory note had an outstanding balance of $965 million and bore interest at a weighted-average interest rate of 6.710%. As of December 31, 2017 and 2016, the amended and restated revolving promissory note and the original revolving promissory note, respectively, are reflected on our consolidated balance sheets as a current liability under “Note payable-affiliate”. In accordance with the terms of the amended and restated revolving promissory note, interest shall be assessed on June 30th and December 31st (an "Interest Period"). Any assessed interest for an Interest Period that remains unpaid on the last day of the subsequent Interest Period is to be capitalized on such date and is to begin accruing interest. As of December 31, 2017, $16 million of accrued interest is reflected in other current liabilities on our consolidated balance sheet.

Interest Expense

Interest expense includes interest on total long-term debt. The following table presents the amount of gross interest expense, net of capitalized interest and interest expense-affiliates, net:



	Years Ended December 31,
	2017			2016		2015
	(Dollars in millions)
Interest expense:
Gross interest expense	$	497		497		491
Capitalized interest	(32		)	(19	)	(18	)
Total interest expense	$	465		478		473
Interest expense-affiliates, net	$	63		59		53

Covenants

Our senior notes were issued under indentures dated April 15, 1990 and October 15, 1999. These indentures contain certain covenants including, but not limited to: (i) a prohibition on certain liens on our assets; and (ii) a limitation on mergers or sales of all, or substantially all, of our assets, which limitation requires that a successor assume the obligation with regard to these notes. These indentures do not contain any cross-default provisions. These indentures do not contain any financial covenants or restrictions on our ability to issue new securities thereunder.

Under the Qwest Corporation term loan, Qwest Corporation must maintain a debt to EBITDA (earnings before interest, taxes, depreciation and amortization, as defined in CenturyLink's Credit Facility) ratio of not more than 2.85:1.0, as of the last day of each fiscal quarter for the four quarters then ended. The term loan also contains a negative pledge covenant, which generally requires us to secure equally and ratably any advances under the term loan if we pledge assets or permit liens on our property for the benefit of other debtholders. The term loan also has a cross payment default and cross acceleration provisions. When present, these provisions could have a wider impact on liquidity than might otherwise arise from a default or acceleration of a single debt instrument. Our debt to EBITDA ratio could be adversely impacted by a wide variety of events, including unforeseen contingencies, many of which are beyond our control. This could reduce our financing flexibility due to potential restrictions on incurring additional debt under certain provisions of our debt agreements or, in certain circumstances, could result in a default under certain provisions of such agreements.

At December 31, 2017, we believe we were in compliance with all of the provisions and covenants contained in our debt agreements.

Accounts Receivable

12 Months Ended

Dec. 31, 2017

Receivables [Abstract]

Accounts Receivable

The following table presents details of our accounts receivable balances:



	As of December 31,
	2017			2016
	(Dollars in millions)
Trade and purchased receivables	$	591		634
Earned and unbilled receivables	99			115
Other	3			4
Total accounts receivable	693			753
Less: allowance for doubtful accounts	(47		)	(53	)
Accounts receivable, less allowance	$	646		700

We are exposed to concentrations of credit risk from residential and business customers within our local service area and from other telecommunications service providers. No customers individually represented more than 10% of our accounts receivable for all periods presented herein. We generally do not require collateral to secure our receivable balances. We have agreements with other telecommunications service providers whereby we agree to bill and collect on their behalf for services rendered by those providers to our customers within our local service area. We purchase accounts receivable from other telecommunications service providers primarily on a recourse basis and include these amounts in our accounts receivable balance. We have not experienced any significant loss associated with these purchased receivables.

The following table presents details of our allowance for doubtful accounts:



	Beginning Balance		Additions	Deductions		Ending Balance
	(Dollars in millions)
2017	$	53	74	(80	)	47
2016	$	47	80	(74	)	53
2015	$	38	78	(69	)	47

- Definition

The entire disclosure for claims held for amounts due a entity, excluding financing receivables. Examples include, but are not limited to, trade accounts receivables, notes receivables, loans receivables. Includes disclosure for allowance for credit losses.

+ References + Details

Property, Plant and Equipment

12 Months Ended

Dec. 31, 2017

Property, Plant and Equipment [Abstract]

Property, Plant and Equipment

Net property, plant and equipment is composed of the following:



	Depreciable Lives	As of December 31,
	Depreciable Lives	2017			2016
		(Dollars in millions)
Property, plant and equipment:
Land	N/A	$	333		348
Fiber, conduit and other outside plant⁽¹⁾	15-45 years	6,639			5,980
Central office and other network electronics⁽²⁾	4-10 years	4,250			3,855
Support assets⁽³⁾	5-30 years	2,620			2,633
Construction in progress⁽⁴⁾	N/A	474			431
Gross property, plant and equipment		14,316			13,247
Accumulated depreciation		(6,392		)	(5,602	)
Net property, plant and equipment		$	7,924		7,645

_______________________________________________________________________________


⁽¹⁾	Fiber, conduit and other outside plant consists of fiber and metallic cable, conduit, poles and other supporting structures.


⁽²⁾	Central office and other network electronics consists of circuit and packet switches, routers, transmission electronics and electronics providing service to customers.


⁽³⁾	Support assets consist of buildings, computers and other administrative and support equipment.


⁽⁴⁾	Construction in progress includes inventory held for construction and property of the aforementioned categories that has not been placed in service as it is still under construction.

We recorded depreciation expense of $912 million, $924 million and $986 million for the years ended December 31, 2017, 2016 and 2015, respectively.

Severance

12 Months Ended

Dec. 31, 2017

Restructuring and Related Activities [Abstract]

Severance

Periodically, we reduce our workforce and accrue liabilities for the related severance costs. These workforce reductions result primarily from the progression or completion of our post-acquisition integration plans related to CenturyLink's indirect acquisition of us, increased competitive pressures, cost reduction initiatives, process improvements through automation and reduced workload demands due to the loss of customers purchasing certain services.

We report severance liabilities within accrued expenses and other liabilities-salaries and benefits in our consolidated balance sheets and report severance expenses in cost of services and products and selling, general and administrative expenses in our consolidated statements of operations.

Changes in our accrued liability for severance expenses were as follows:



	Severance
	(Dollars in millions)
Balance at December 31, 2015	$	6
Accrued to expense	89
Payments, net	(43		)
Balance at December 31, 2016	52
Accrued to expense	14
Payments, net	(58		)
Balance at December 31, 2017	$	8

Employee Benefits	12 Months Ended
Employee Benefits	Dec. 31, 2017
Retirement Benefits [Abstract]
Employee Benefits	Employee Benefits Pension and Post-Retirement Benefits QCII's post-retirement benefit plans were merged into CenturyLink's post-retirement benefit plans on January 1, 2012 and on December 31, 2014, QCII's qualified pension plan and a pension plan of an affiliate were merged into the CenturyLink Retirement Plan, which was renamed the CenturyLink Combined Pension Plan. Prior to the plan mergers, a substantial portion of our active and retired employees participated in QCII's pension and post-retirement plans. Based on current laws and circumstances, (i) CenturyLink was not required to make a cash contribution to the CenturyLink Combined Pension Plan in 2017 and (ii) CenturyLink does not expect it will be required to make a contribution in 2018. The amount of required contributions to the CenturyLink Combined Pension Plan in 2019 and beyond will depend on earnings on plan investments, prevailing discount rates, demographic experience, changes in plan benefits and changes in funding laws and regulations. CenturyLink occasionally makes voluntary contributions in addition to required contributions, and CenturyLink made such voluntary cash contributions of $100 million to the CenturyLink Combined Pension Plan during each of the third quarters of 2017 and 2016. CenturyLink currently expects to make a voluntary contribution of $100 million to the trust for its qualified pension plan in 2018. No contributions were made to the post-retirement occupational health care trust in 2017 or 2016 and CenturyLink does not expect to make a contribution in 2018. The unfunded status of CenturyLink's qualified pension plan for accounting purposes was $2.004 billion and $2.352 billion as of December 31, 2017 and 2016, respectively, which includes the merged QCII qualified pension plan. The unfunded status of CenturyLink's post-retirement benefit plans for accounting purposes was $3.352 billion and $3.360 billion as of December 31, 2017 and 2016, respectively. In 2015, our ultimate parent company, CenturyLink, changed their allocation methodology with respect to their now centrally managed pension and post-retirement plans. Specifically, under this new methodology, CenturyLink will allocate current service costs to subsidiaries relative to employees who are currently earning benefits under the pension and post-retirement benefit plans. The net periodic benefit cost allocated to us is now paid on a monthly basis through CenturyLink’s intercompany cash management process. The affiliate obligations, net in current and noncurrent liabilities on the consolidated balance sheets primarily represents the cumulative allocation of expense, net of payments, associated with QCII's pension plans and post-retirement benefits plans prior to the plan mergers. In 2015, we agreed to a plan to settle the outstanding pension and post-retirement affiliate obligations, net balance with QCII over a 30 year term. Under the plan, payments are scheduled to be made on a monthly basis. For the years ended December 31, 2017 and 2016, we made settlement payments in the aggregate of $87 million and $97 million, respectively, to QCII under the plan. Changes in the affiliate obligations, net are reflected in operating activities on our consolidated statements of cash flows. We were allocated $44 million of pension service costs and $12 million of post-retirement service costs during the year ended December 31, 2017, which represented 70% of CenturyLink's total pension and post-retirement service costs for the year. The combined net pension and post-retirement service costs is included in cost of services and products and selling, general and administrative expenses on our consolidated statement of operations for the year ended December 31, 2017. We were allocated $45 million of pension service costs and $14 million of post-retirement service costs during the year ended December 31, 2016, which represented 70% of CenturyLink's total pension and post-retirement service costs for the year. The combined net pension and post-retirement service costs is included in cost of services and products and selling, general and administrative expenses on our consolidated statement of operations for the year ended December 31, 2016. We were allocated $57 million of pension service costs and $17 million of post-retirement service costs during the year ended December 31, 2015, which represented 69% of CenturyLink's total pension and post-retirement service costs for the year. The combined net pension and post-retirement service costs is included in cost of services and products and selling, general and administrative expenses on our consolidated statement of operations for the year ended December 31, 2015. CenturyLink sponsors a noncontributory qualified defined benefit pension plan that covers substantially all of our employees. As noted above, on December 31, 2014, QCII's pension plan was merged into the CenturyLink Retirement Plan, which was renamed the CenturyLink Combined Pension Plan. The plan also provides survivor and disability benefits to certain employees. In November 2009, and prior to the plan merger, the pension plan was amended to no longer provide pension benefit accruals for active non-represented employees after December 31, 2009. In addition, non-represented employees hired after January 1, 2009 are not eligible to participate in the plans. Active non-represented employees who participate in these plans retain their accrued pension benefit earned as of December 31, 2009 and certain participants will continue to earn interest credits on their benefit after December 31, 2009. Employees are eligible to receive their vested accrued benefit when they separate from CenturyLink. The plans also provided a death benefit for eligible beneficiaries of certain retirees; however, the plan was amended to eliminate this benefit effective March 1, 2010 for retirees who retired prior to January 1, 2004 and whose deaths occur after February 28, 2010 and eliminate the death benefit for eligible beneficiaries of certain retirees who retired after December 31, 2003. CenturyLink maintains post-retirement benefit plans that provide health care and life insurance benefits for certain eligible retirees. The QCII post-retirement benefit plans were merged into CenturyLink's post-retirement benefit plans on January 1, 2012. The benefit obligation for the occupational health care and life insurance post-retirement plans is estimated based on the terms of benefit plans. In calculating this obligation, CenturyLink considers numerous assumptions, estimates and judgments, including but not limited to, discount rates, health care cost trend rates and plan amendments. In June 2017, we renewed a collective bargaining agreement for three years which covers approximately 10,000 of our unionized employees. Effective with the renewal, there were no significant changes to the existing benefits for the approximately 10,000 active employees and eligible post-1990 retirees who are former represented employees. This agreement expires in March 2020. The terms of the post-retirement health care and life insurance plans between CenturyLink and its eligible non-represented employees and its eligible post-1990 non-represented retirees are established by CenturyLink and are subject to change at its discretion. CenturyLink has a practice of sharing some of the cost of providing health care benefits with its non-represented employees and post-1990 non-represented retirees. The benefit obligation for the non-represented post-retirement health care benefits is based on the terms of the current written plan documents and is adjusted for anticipated continued cost sharing with non-represented employees and post-1990 non-represented retirees. However, CenturyLink's contribution under its post-1990 non-represented retirees' health care plan is capped at a specific dollar amount. Medicare Prescription Drug, Improvement and Modernization Act of 2003 CenturyLink sponsors post-retirement health care plans with several benefit options that provide prescription drug benefits that CenturyLink deems actuarially equivalent to or exceeding Medicare Part D. CenturyLink recognizes the impact of the federal subsidy received under the Medicare Prescription Drug, Improvement and Modernization Act of 2003 in the calculation of its post-retirement benefit obligation and net periodic post-retirement benefit expense. Other Benefit Plans Health Care and Life Insurance We provide health care and life insurance benefits to essentially all of our active employees. We are largely self-funded for the cost of the health care plan. Our health care benefit expense for current employees was $204 million, $241 million and $217 million for the years ended December 31, 2017, 2016 and 2015, respectively. Union-represented employee benefits are based on negotiated collective bargaining agreements. Employees' group basic life insurance plans are fully insured and the premiums are paid by CenturyLink. 401(k) Plans CenturyLink sponsors qualified defined contribution plans covering substantially all of our employees. Under these plans, employees may contribute a percentage of their annual compensation up to certain maximums, as defined by the plans and by the Internal Revenue Service ("IRS"). Currently, we match a percentage of our employees' contributions in cash. We recognized $42 million, $42 million and $43 million in expense related to these plans for the years ended December 31, 2017, 2016 and 2015, respectively.

Share-Based Compensation	12 Months Ended
Share-Based Compensation	Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-Based Compensation	Share-based Compensation Share-based compensation expenses are included in cost of services and products, and selling, general, and administrative expenses in our consolidated statements of operations. For the years ended December 31, 2017, 2016 and 2015, we recorded a share-based compensation expense of approximately $27 million, $22 million and $21 million, respectively. We recognized an income tax benefit from our compensation expense of approximately $7 million, $8 million and $8 million, respectively, during the years ended December 31, 2017, 2016 and 2015, respectively.

Products and Services Revenues

12 Months Ended

Dec. 31, 2017

Segment Reporting [Abstract]

Products and Services Revenues

We are an integrated communications company engaged primarily in providing an array of communications services, including local voice, broadband, private line (including business data services), Ethernet, network access, information technology and other ancillary services. We strive to maintain our customer relationships by, among other things, bundling our service offerings to provide our customers with a complete offering of integrated communications services.

We categorize our products, services and revenues among the following three categories:


•	Strategic services, which include primarily broadband, Ethernet and other ancillary services;


•	Legacy services, which include primarily local voice, private line (including business data services), Integrated Services Digital Network ("ISDN") services (which use regular telephone lines to support voice, video and data applications), switched access and other ancillary services; and

•

Affiliates and other services, which consist primarily of CAF support payments, USF support payments, USF surcharges and services we provide to our affiliates. We receive federal support payments from both Phase 1 and Phase 2 of the CAF program, and support payments from both federal and state USF programs. These support payments are government subsidies designed to reimburse us for various costs related to certain telecommunications services, including the costs of deploying, maintaining and operating voice and broadband infrastructure in high-cost rural areas where we are not able to fully recover our costs from our customers. We also collect USF surcharges based on specific services we list on our customers' invoices to fund the FCC's universal service programs. We provide to our affiliates, telecommunication services that we also provide to external customers. In addition, we provide to our affiliates, computer system development and support services, network support and technical services.

Our operating revenues for our products and services consisted of the following categories for the years ended December 31, 2017, 2016 and 2015:



	Years Ended December 31,
	2017		2016	2015
	(Dollars in millions)
Strategic services	$	2,686	2,696	2,617
Legacy services	2,831		3,216	3,593
Affiliates and other services	3,033		2,998	2,754
Total operating revenues	$	8,550	8,910	8,964

We do not have any single external customer that provides more than 10% of our total consolidated operating revenues. Substantially all of our consolidated revenues come from customers located in the United States.

We recognize revenues in our consolidated statements of operations for certain USF surcharges and transaction taxes that we bill to our customers. Our consolidated statements of operations also reflect the offsetting expense for the amounts we remit to the government agencies. The total amount of such surcharges and transaction taxes that we included in revenues aggregated to $134 million, $149 million and $147 million for the years ended December 31, 2017, 2016 and 2015, respectively. These USF surcharges, where we record revenue, are included in "other" operating revenues and transaction taxes are included in "legacy services" revenues. We also act as a collection agent for certain other USF and transaction taxes that we are required by government agencies to bill our customers, for which we do not record any revenue or expense because we only act as a pass-through agent.

Our operations are integrated into and reported as part of the consolidated segment data of CenturyLink. CenturyLink's chief operating decision maker ("CODM") is our CODM, but reviews our financial information on an aggregate basis only in connection with our quarterly and annual reports that we file with the Securities and Exchange Commission. Consequently, we do not provide our discrete financial information to the CODM on a regular basis. As such, we believe we have one reportable segment.

Affiliate Transactions

12 Months Ended

Dec. 31, 2017

Affiliate Transactions

We provide to our affiliates, telecommunications services that we also provide to external customers. In addition, we provide to our affiliates, computer system development and support services and network support and technical services.

Below are details of the services we provide to our affiliates:


•	Telecommunications services. Data, broadband and voice services in support of our affiliates' service offerings;

•

Computer system development and support services. Information technology services primarily include the labor cost of developing, testing and implementing the system changes necessary to support order entry, provisioning, billing, network and financial systems, as well as the cost of improving, maintaining and operating our operations support systems and shared internal communications networks; and


•	Network support and technical services. Network support and technical services relate to forecasting demand volumes and developing plans around network utilization and optimization, developing and implementing plans for overall product development, provisioning and customer care.

We charge our affiliates for services that we also provide to external customers, while other services that we provide only to our affiliates are priced by applying a fully distributed cost ("FDC") methodology. FDC rates include salaries and wages, payroll taxes, employee related benefits, miscellaneous expenses, and charges for the use of our buildings, computing and software assets. Whenever possible, costs are directly assigned to our affiliates for the services they use. If costs cannot be directly assigned, they are allocated among all affiliates based upon cost causative measures; or if no cost causative measure is available, these costs are allocated based on a general allocator. These cost allocation methodologies are reasonable. From time to time, we adjust the basis for allocating the costs of a shared service among affiliates. Such changes in allocation methodologies are generally billed prospectively.

We also purchase services from our affiliates including telecommunication services, insurance, flight services and other support services such as legal, regulatory, finance and accounting, tax, human resources and executive support. Our affiliates charge us for these services based on FDC.

Income Taxes

12 Months Ended

Dec. 31, 2017

Income Tax Disclosure [Abstract]

Income Taxes

On December 22, 2017, the Tax Cuts and Jobs Act (the "Act") was signed into law. The Act significantly changes U.S. tax law. The Act reduces the U.S. corporate income tax rate from a maximum of 35% to 21% for all corporations, effective January 1, 2018, and makes certain changes to U.S. taxation of income earned by foreign subsidiaries, capital expenditures, interest expense and various other items.

As a result of the reduction in the U.S. corporate income tax rate from 35% to 21%, we re-measured our net deferred tax liabilities at December 31, 2017 and recognized a provisional tax benefit of $555 million in our consolidated statement of operations for the year ended December 31, 2017.

On December 22, 2017, the SEC staff addressed the application of U.S. GAAP in situations when a registrant does not have the necessary information available, prepared or analyzed (including computations) in reasonable detail to complete the accounting for certain income tax effects of the Act. We have provisionally recognized the tax impacts related to the re-measurement of deferred tax assets and liabilities in the amount noted above in our consolidated financial statements for the year ended December 31, 2017. The ultimate impact may differ from our provisional amount due to additional analysis, changes in interpretations and assumptions we have made, additional regulatory guidance that may be issued, and actions we may take as a result of the Act. The change from our current provisional estimates will be reflected in our future statements of operations and could be material. We expect to complete the accounting by the time we file our 2017 U.S. corporate income tax return in the fourth quarter of 2018, although we cannot assure you of this.

We are included in the consolidated federal income tax returns and the combined state income tax returns of CenturyLink. CenturyLink treats our consolidated results as if we were a separate taxpayer. The policy requires us to settle our tax liabilities through a change in our general intercompany obligation based upon our separate return taxable income, which is reflected in advances to affiliates on our consolidated balance sheets. Because we are included in the consolidated federal income tax returns and the combined state income tax returns of CenturyLink, any tax audits involving CenturyLink will also involve us. We, or at least one of our subsidiaries, file income tax returns in various states jurisdictions.

With few exceptions, we are no longer subject to U.S. federal, state and local or non-U.S. income tax examinations by tax authorities for years before 2008. The Internal Revenue Service and state and local taxing authorities reserve the right to audit any period where net operating loss carryforwards are available.

As of December 31, 2017 and 2016, we had no liability for interest related to uncertain tax positions. Additionally, we did not record interest expense related to uncertain tax positions for the years ended December 31, 2017, 2016 and 2015. We made no accrual for penalties related to income tax positions.

Income Tax Expense

The components of the income tax expense from continuing operations are as follows:



	Years Ended December 31,
	2017			2016		2015
	(Dollars in millions)
Income tax expense:
Current:
Federal and foreign	$	777		686		734
State and local	130			115		114
Total current	907			801		848
Deferred:
Federal and foreign	(736		)	(103	)	(170	)
State and local	(37		)	(20	)	(19	)
Total deferred	(773		)	(123	)	(189	)
Income tax expense	$	134		678		659

The effective income tax rate for continuing operations differs from the statutory tax rate as follows:



	Years Ended December 31,
	2017		2016		2015
	(in percent)
Effective income tax rate:
Federal statutory income tax rate	35.0	%	35.0	%	35.0	%
State income taxes-net of federal effect	3.4	%	3.5	%	3.6	%
Tax reform	(31.0	)%	—	%	—	%
Other	0.1	%	—	%	(0.6	)%
Effective income tax rate	7.5	%	38.5	%	38.0	%

The effective tax rate for the year ended December 31, 2017 reflects the benefit of $555 million from the re-measurement of deferred taxes as noted above.

Deferred Tax Assets and Liabilities

The tax effects of temporary differences that gave rise to significant portions of the deferred tax assets and deferred tax liabilities were as follows:



	As of December 31,
	2017			2016
	(Dollars in millions)
Deferred tax assets and liabilities:
Deferred tax liabilities:
Property, plant and equipment	$	(933	)	(1,384	)
Intangibles assets	(553		)	(1,088	)
Receivable from an affiliate due to pension plan participation	—			(452	)
Total deferred tax liabilities	(1,486		)	(2,924	)
Deferred tax assets:
Payable to affiliate due to post-retirement benefit plan participation	366			954
Other	127			209
Gross deferred tax assets	493			1,163
Less valuation allowance on deferred tax assets	(8		)	(12	)
Net deferred tax assets	485			1,151
Net deferred tax liabilities	$	(1,001	)	(1,773	)

At December 31, 2017, we have established a valuation allowance of $8 million as it is not more likely than not that this amount of deferred tax assets will be realized. There was a $4 million change to the valuation allowance in 2017, all attributable to tax reform.

Other Income Tax Information

We paid $907 million, $801 million and $848 million to QSC related to income taxes in the years ended December 31, 2017, 2016 and 2015, respectively.

Fair Value Disclosure

12 Months Ended

Dec. 31, 2017

Fair Value Disclosures [Abstract]

Fair Value Disclosure

Our financial instruments consist of cash and cash equivalents, accounts receivable, advances to affiliates, accounts payable, note payable-affiliate and long-term debt, excluding capital lease and other obligations. Due to their short-term nature, the carrying amounts of our cash and cash equivalents, accounts receivable, advances to affiliates, accounts payable and note payable-affiliate approximate their fair values.

Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between independent and knowledgeable parties who are willing and able to transact for an asset or liability at the measurement date. We use valuation techniques that maximize the use of observable inputs and minimize the use of unobservable inputs when determining fair value and then we rank the estimated values based on the reliability of the inputs used following the fair value hierarchy set forth by the FASB. We determined the fair values of our long-term debt, including the current portion, based on quoted market prices where available or, if not available, based on discounted future cash flows using current market interest rates.

The three input levels in the hierarchy of fair value measurements are defined by the FASB generally as follows:



Input Level		Description of Input

Level 1		Observable inputs such as quoted market prices in active markets.
Level 2		Inputs other than quoted prices in active markets that are either directly or indirectly observable.
Level 3		Unobservable inputs in which little or no market data exists.

The following table presents the carrying amounts and estimated fair values of our long-term debt, excluding capital lease and other obligations, as well as the input levels used to determine the fair values:



		As of December 31, 2017			As of December 31, 2016
	Input Level	Carrying Amount		Fair Value	Carrying Amount	Fair Value
		(Dollars in millions)
Liabilities-Long-term debt (excluding capital lease and other obligations)	2	$	7,245	7,080	7,229	7,203

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Stockholder's Equity

12 Months Ended

Dec. 31, 2017

Stockholders' Equity Note [Abstract]

Stockholder's Equity

Common Stock

We have one share of common stock (no par value) issued and outstanding, which is owned by QSC.

In addition, in the normal course of business, we transfer assets and liabilities to and from QSC and its affiliates, which are recorded through our equity. It is our policy to record these asset transfers based on carrying values.

Dividends

We declared the following cash dividend to QSC:



	Years Ended December 31,
	2017		2016	2015
	(Dollars in millions)
Cash dividend declared to QSC	$	1,000	1,300	1,350
Cash dividend paid to QSC	1,000		1,300	1,350

The timing of cash payments for declared dividends to QSC is at our discretion in consultation with QSC. We may declare and pay dividends to QSC in excess of our earnings to the extent permitted by applicable law. Our debt covenants do not limit the amount of dividends we can pay to QSC.

On March 31, 2017, we distributed our equity interest valued at $12 million in a limited liability company to QSC. The limited liability company's sole asset was a building that was being utilized by an affiliate.

Quarterly Financial Data (Unaudited)

12 Months Ended

Dec. 31, 2017

Quarterly Financial Information Disclosure [Abstract]

Quarterly Financial Data (Unaudited)



	First Quarter		Second Quarter	Third Quarter	Fourth Quarter		Total
	(Dollars in millions)
2017
Operating revenues	$	2,162	2,133	2,141	2,114		8,550
Operating income	580		573	560	600		2,313
Income tax expense (benefit)	174		170	168	(378	)	134
Net income	278		268	265	846		1,657



	First Quarter		Second Quarter	Third Quarter	Fourth Quarter	Total
	(Dollars in millions)
2016
Operating revenues	$	2,253	2,223	2,226	2,208	8,910
Operating income	625		602	576	521	2,324
Income tax expense	188		179	159	152	678
Net income	304		288	255	238	1,085

In the fourth quarter of 2017, we recognized a tax benefit of $555 million due to the change in the federal corporate tax rate from 35% to 21%. During the fourth quarter of 2016, we recognized $78 million of severance expenses and other one-time termination benefits associated with workforce reductions.

Commitments and Contingencies

12 Months Ended

Dec. 31, 2017

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

Pending Matters

We are vigorously defending against all of the matters described below. As a matter of course, we are prepared to both litigate these matters to judgment, as well as to evaluate and consider all reasonable settlement opportunities. In this Note, when we refer to a class action as "putative" it is because a class has been alleged, but not certified in that matter. We have established accrued liabilities for these matters described below where losses are deemed probable and reasonably estimable.

Switched Access Disputes

Subsidiaries of CenturyLink, Inc., including us, are among hundreds of companies involved in an industry-wide dispute, raised in nearly 100 federal lawsuits (filed between 2014 and 2016) that have been consolidated in the United States District Court for the Northern District of Texas for pretrial procedures. The disputes relate to switched access charges that local exchange carriers ("LECs") collect from interexchange carriers ("IXCs") for IXCs' use of LEC's access services. In the lawsuits, IXCs, including Sprint Communications Company L.P. and various affiliates of Verizon Communications Inc., assert that federal and state laws bar LECs from collecting access charges when IXCs exchange certain types of calls between mobile and wireline devices that are routed through an IXC. Some of these IXCs have asserted claims seeking refunds of payments for access charges previously paid and relief from future access charges.

In November 2015, the federal court agreed with the LECs and rejected the IXCs' contention that federal law prohibits these particular access charges, and also allowed the IXCs to refile state-law claims. Since then, many of the LECs and IXCs have filed revised pleadings and additional motions, which remain pending. Separately, some of the defendants, including us, have petitioned the FCC to address these issues on an industry-wide basis.

The outcome of these disputes and lawsuits, as well as any related regulatory proceedings that could ensue, are currently not predictable. If we are required to stop assessing these charges or to pay refunds of any such charges, our financial results could be negatively affected.

Billing Practices Suits

In June 2017, a former employee of CenturyLink filed an employment lawsuit against CenturyLink claiming that she was wrongfully terminated for alleging that CenturyLink charged some of its retail customers for products and services they did not authorize. Starting shortly thereafter and continuing since then, and based in part on the allegations made by the former employee, a series of consumer and shareholder putative class actions were filed against CenturyLink, and it received several shareholder derivative demands. In July 2017, the Minnesota Attorney General also filed a civil suit on behalf of the Minnesota consumers alleging that we and certain of our affiliates engaged in improper sales and billing practices. The filing of additional related lawsuits is possible. The consumer putative class actions have been transferred to the U.S. District Court for the District of Minnesota for coordinated and consolidated pretrial proceedings. The shareholder putative class actions have been consolidated into a single action that currently is pending in U.S. District Court for the Western District of Louisiana. In addition, a separate, related class action was filed in U.S. District Court for the Southern District of New York purportedly on behalf of persons who purchased certain of CenturyLink's Senior Notes. This class action suit has been transferred to the U.S. District Court for the Western District of Louisiana. Although CenturyLink and/or various of its subsidiaries are named in these lawsuits, Qwest Corporation is currently a named defendant in only the Minnesota Attorney General civil suit.

In late June 2017, CenturyLink's Board of Directors formed a special committee of outside directors to investigate improper sales and billing practices and related matters. In late 2017, the special committee concluded its review and issued its key findings. Among other things, the committee found that (i) our investment in consumer sales monitoring was insufficient, (ii) our ordering and billing software contributed to customer confusion and (iii) systems and human errors contributed to inaccurate billing. In August 2017, CenturyLink's Board of Directors formed a special litigation committee of outside directors to address the allegations of impropriety contained in the shareholder derivative demands. The investigation of the special litigation committee is ongoing.

Other Proceedings and Disputes

From time to time, we are involved in other proceedings incidental to our business, including patent infringement allegations, administrative hearings of state public utility commissions relating primarily to our rates or services, actions relating to employee claims, various tax issues, environmental law issues, grievance hearings before labor regulatory agencies and miscellaneous third party tort actions.

We are currently defending several patent infringement lawsuits asserted against us by non-practicing entities, many of which are seeking substantial recoveries. These cases have progressed to various stages and one or more may go to trial in the coming 24 months if they are not otherwise resolved. Where applicable, we are seeking full or partial indemnification from our vendors and suppliers. As with all litigation, we are vigorously defending these actions and, as a matter of course, are prepared to litigate these matters to judgment, as well as to evaluate and consider all reasonable settlement opportunities.

We are subject to various federal, state and local environmental protection and health and safety laws. From time to time, we are subject to judicial and administrative proceedings brought by various governmental authorities under these laws. Several such proceedings are currently pending, but none is reasonably expected to exceed $100,000 in fines and penalties.

The outcome of these other proceedings is not predictable. However, based on current circumstances, we do not believe that the ultimate resolution of these other proceedings, after considering available defenses and any insurance coverage or indemnification rights, will have a material adverse effect on our financial position, results of operations or cash flows.

CenturyLink, Inc. and its affiliates are involved in several legal proceedings to which we are not a party that, if resolved against them, could have a material adverse effect on their business and financial condition. As an indirect wholly-owned subsidiary of CenturyLink, Inc., our business and financial condition could be similarly affected. You can find descriptions of these legal proceedings in CenturyLink, Inc.'s quarterly and annual reports filed with the Securities and Exchange Commission. Because we are not a party to any of the matters, we have not accrued any liabilities for the matters.

_________________

The ultimate outcome of the above-described matters may differ materially from the outcomes anticipated, estimated, projected or implied by us in certain of our forward-looking statements appearing above in this Note, and proceedings currently viewed as immaterial by us may ultimately materially impact us. For more information, see “Risk Factors—Risks Relating to Legal and Regulatory Matters—Our pending legal proceedings could have a material adverse impact on our financial condition and operating results, on the trading price of our securities and on our ability to access the capital markets” in Item 1A of Part I of this report.

Capital Leases

We lease certain facilities and equipment under various capital lease arrangements. Depreciation of assets under capital leases is included in depreciation and amortization expense in our consolidated statements of operations. Payments on capital leases are included in repayments of long-term debt, including current maturities in our consolidated statements of cash flows.

The tables below summarize our capital lease activity:



	Years Ended December 31,
	2017		2016	2015
	(Dollars in millions)
Assets acquired through capital leases	$	19	10	10
Depreciation expense	9		5	19
Cash payments towards capital leases	8		6	20



	As of December 31,
	2017		2016
	(Dollars in millions)
Assets included in property, plant and equipment	$	57	40
Accumulated depreciation	24		22

The future annual minimum payments under capital lease arrangements as of December 31, 2017 were as follows:



	Future Minimum Payments
	(Dollars in millions)
Capital lease obligations:
2018	$	14
2019	10
2020	6
2021	2
2022	1
2023 and thereafter	3
Total minimum payments	36
Less: amount representing interest and executory costs	(6		)
Present value of minimum payments	30
Less: current portion	(12		)
Long-term portion	$	18

Operating Leases

We lease various equipment, office facilities, retail outlets, switching facilities and other network sites. These leases, with few exceptions, provide for renewal options and escalations that are either fixed or based on the consumer price index. Any rent abatements, along with rent escalations, are included in the computation of rent expense calculated on a straight-line basis over the lease term. The lease term for most leases includes the initial non-cancelable term plus any term under renewal options that are reasonably assured. For the years ended December 31, 2017, 2016 and 2015, our gross rental expense was $70 million, $72 million and $75 million, respectively. We also received sublease rental income for the years ended December 31, 2017, 2016 and 2015 of $2 million, $4 million and $4 million, respectively.

At December 31, 2017, our future rental commitments for operating leases were as follows:



	Future Minimum Payments
	(Dollars in millions)
Operating leases:
2018	$	36
2019	31
2020	24
2021	22
2022	18
2023 and thereafter	46
Total future minimum payments⁽¹⁾	$	177

_______________________________________________________________________________


⁽¹⁾	Minimum payments have not been reduced by minimum sublease rentals of $22 million due in the future under non-cancelable subleases.

Purchase Commitments

We have several commitments primarily for marketing activities and support services from a variety of vendors to be used in the ordinary course of business totaling $59 million at December 31, 2017. Of this amount, we expect to purchase $48 million in 2018 and $11 million in 2019. These amounts do not represent our entire anticipated purchases in the future, but represent only those items for which we were contractually committed as of December 31, 2017.

Other Financial Information

12 Months Ended

Dec. 31, 2017

Additional Financial Information Disclosure [Abstract]

Other Financial Information

Other Current Assets

The following table presents details of other current assets in our consolidated balance sheets:



	As of December 31,
	2017		2016
	(Dollars in millions)
Prepaid expenses	$	42	48
Assets held for sale	—		8
Other	56		73
Total other current assets	$	98	129

We recorded a loss of $11 million in connection with the impairment of an office building being reclassified as held for sale in 2016. This impairment charge is included in selling, general and administrative expense in our consolidated statement of operations for the year ended December 31, 2016. The sale of the office building closed in 2017.

Selected Current Liabilities

Current liabilities reflected in our consolidated balance sheets include accounts payable:

Included in accounts payable at December 31, 2017 and 2016, were $86 million and $53 million, respectively, associated with capital expenditures.

Labor Union Contracts	12 Months Ended
Labor Union Contracts	Dec. 31, 2017
Labor Union Contracts
Labor Union Contracts	Labor Union Contracts As of December 31, 2017, approximately 10,000, or 45% of our employees were members of various bargaining units represented by the Communication Workers of America ("CWA") and the International Brotherhood of Electrical Workers ("IBEW"). We believe that relations with our employees continue to be generally good. In mid-2017, we reached new agreements with the CWA District 7 and IBEW Local 206, which represented at December 31, 2017 substantially all of the above noted represented employees. The new agreements were effective June 18, 2017 and will expire on March 8, 2020 and include terms substantially similar to those contained in the prior agreements.

Basis of Presentation and Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Consolidation	The accompanying consolidated financial statements include our accounts and the accounts of our subsidiaries. Intercompany amounts and transactions with our consolidated subsidiaries have been eliminated. Transactions with our non-consolidated affiliates (referred to herein as affiliates) have not been eliminated.
Reclassifications	We reclassified certain prior period amounts to conform to the current period presentation, including the categorization of our revenues for 2016 and 2015. See Note 9—Products and Services Revenues for additional information. These changes had no impact on total operating revenues, total operating expenses or net income for any period presented.
Use of Estimates	Use of Estimates Our consolidated financial statements are prepared in accordance with U.S. generally accepted accounting principles. These accounting principles require us to make certain estimates, judgments and assumptions. We believe that the estimates, judgments and assumptions we make when accounting for specific items and matters, including, but not limited to, long-term contracts, customer retention patterns, allowance for doubtful accounts, depreciation, amortization, asset valuations, rates used for affiliate cost allocations, internal labor capitalization rates, recoverability of assets (including deferred tax assets), impairment assessments, taxes, certain liabilities and other provisions and contingencies, are reasonable, based on information available at the time they are made. Our accounting for CenturyLink's indirect acquisition of us required extensive use of estimates in determining the acquisition date fair values of our assets and liabilities. These estimates, judgments and assumptions can materially affect the reported amounts of assets, liabilities and components of stockholder's equity as of the dates of the consolidated balance sheets, as well as the reported amounts of revenues, expenses and components of cash flows during the periods presented in our other consolidated financial statements. We also make estimates in our assessments of potential losses in relation to threatened or pending tax and legal matters. See Note 11—Income Taxes and Note 15—Commitments and Contingencies for additional information. For matters not related to income taxes, if a loss is considered probable and the amount can be reasonably estimated, we recognize an expense for the estimated loss. If we have the potential to recover a portion of the estimated loss from a third party, we make a separate assessment of recoverability and reduce the estimated loss if recovery is also deemed probable. For matters related to income taxes, if we determine that the impact of an uncertain tax position is more likely than not to be sustained upon audit by the relevant taxing authority, then we recognize a benefit for the largest amount that is more likely than not to be sustained. No portion of an uncertain tax position will be recognized if the position has less than a 50% likelihood of being sustained. Interest is recognized on the amount of unrecognized benefit from uncertain tax positions. For all of these and other matters, actual results could differ materially from our estimates.
Revenue Recognition	Revenue Recognition We recognize revenue for services when the related services are provided. Recognition of certain payments received in advance of services being provided is deferred until the service is provided. These advance payments include activation and installation charges, which we recognize as revenue over the expected customer relationship period, which ranges from three to seven years depending on the service. We also defer costs for customer activations and installations. The deferral of customer activation and installation costs is limited to the amount of revenue deferred on advance payments. Costs in excess of advance payments are recorded as expense in the period such costs are incurred. Expected customer relationship periods are estimated using historical experience. In most cases, termination fees or other fees on existing contracts that are negotiated in conjunction with new contracts are deferred and recognized over the new contract term. We offer bundle discounts to our customers who receive certain groupings of services. These bundle discounts are recognized concurrently with the associated revenue and are allocated to the various services in the bundled offering based on the estimated selling price of services included in each bundled combination. Customer arrangements that include both equipment and services are evaluated to determine whether the elements are separable. If the elements are deemed separable and separate earnings processes exist, the revenue associated with the customer arrangement is allocated to each element based on the relative estimated selling price of the separate elements. We have estimated the selling prices of each element by reference to vendor-specific objective evidence of selling prices when the elements are sold separately. The revenue associated with each element is then recognized as earned. For example, if we receive an advance payment when we sell equipment and continuing service together, we immediately recognize as revenue the amount allocated to the equipment as long as all the conditions for revenue recognition have been satisfied. The portion of the advance payment allocated to the service based upon its relative selling price is recognized ratably over the longer of the contractual period or the expected customer relationship period. In connection with offering products and services provided by third-party vendors, we review the relationship between us, the vendor and the end customer to assess whether revenue should be reported on a gross or net basis. In assessing whether revenue should be reported on a gross or net basis, we consider whether we act as a principal in the transaction, take title to the products, have risk and rewards of ownership or act as an agent or broker.
Affiliate Transactions	Affiliate Transactions We provide to our affiliates telecommunications services that we also provide to external customers. In addition, we provide to our affiliates computer system development and support services. Services provided by us to our affiliates are recognized as operating revenue-affiliates in our consolidated statements of operations. We also purchase services from our affiliates including telecommunications services, marketing and employee-related support services. Services provided to us from our affiliates are recognized as operating expenses-affiliates on our consolidated statements of operations. Because of the significance of the services we provide to our affiliates and our affiliates provide to us, the results of operations, financial position and cash flows presented herein are not necessarily indicative of the results of operations, financial position and cash flows we would have achieved had we operated as a stand-alone entity during the periods presented. We recognize intercompany charges at the amounts billed to us by our affiliates and we recognize intercompany revenue for services we bill to our affiliates. Regulatory rules require certain revenues and expenses to be recorded at market price or fully distributed cost. Our compliance with regulations is subject to review by regulators. Adjustments to intercompany charges that result from these reviews are recorded in the period they become known. CenturyLink has cash management arrangements between certain of its subsidiaries that include lines of credit, affiliate obligations, capital contributions and dividends. As part of these cash management arrangements, an affiliate provides lines of credit to certain other affiliates. Amounts outstanding under these lines of credit and intercompany obligations vary from time to time. Under these arrangements, the majority of our cash balance is transferred on a daily basis to CenturyLink and most affiliate transactions are deemed to be settled at the time the transactions are recorded in our accounting records, with the resulting net balance at the end of each period reflected as advances to affiliates on the accompanying consolidated balance sheets. From time to time we declare and pay dividends to our parent, QSC, which are settled through the advances to affiliates, which has the net effect of reducing the amount of these advances. Dividends declared are reflected on our consolidated statements of stockholder's equity and the consolidated statements of cash flows reflects the changes in advances to affiliates as investing activities and changes in advances from affiliates as financing activities. Interest is assessed on the advances to/from affiliates on either the three-month U.S T-bill rate (for advances to affiliates) or CenturyLink’s weighted average borrowing rate (for advances from affiliates). The affiliate obligations, net in current and noncurrent liabilities on our consolidated balance sheets primarily represents the cumulative allocation of expense, net of payments, associated with QCII’s pension plans and post-retirement benefits plans prior to the plan mergers. In 2015, we agreed to a plan to settle the outstanding affiliate obligations, net balance with QCII over a 30 year term. Under the plan, payments are scheduled to be made on a monthly basis. For the years ended December 31, 2017 and 2016, we made settlement payments of $87 million and $97 million, respectively, to QCII in accordance with plan. Changes in the affiliate obligations, net are reflected in operating activities on our consolidated statements of cash flows. In the normal course of business, we transfer assets to and from various affiliates through our parent, QSC, which are recorded through our equity. It is our policy to record asset transfers based on carrying values.
USF, Gross Receipts Taxes and Other Surcharges	USF Surcharges, Gross Receipts Taxes and Other Surcharges In determining whether to include in our revenues and expenses the taxes and surcharges collected from customers and remitted to government authorities, including USF surcharges, sales, use, value added and some excise taxes, we assess, among other things, whether we are the primary obligor or principal taxpayer for the taxes assessed in each jurisdiction where we do business. In jurisdictions where we determine that we are the principal taxpayer, we record the surcharges on a gross basis and include them in our revenues and costs of services and products. In jurisdictions where we determine that we are merely a collection agent for the government authority, we record the taxes on a net basis and do not include them in our revenues and costs of services and products.
Advertising Costs	Advertising Costs Costs related to advertising are expensed as incurred and included in selling, general and administrative expenses in our consolidated statements of operations. Our advertising expense was $139 million, $91 million and $84 million for the years ended December 31, 2017, 2016 and 2015, respectively.
Legal Costs	Legal Costs In the normal course of our business, we incur costs to hire and retain external legal counsel to advise us on regulatory, litigation and other matters. We expense these costs as the related services are received.
Income Taxes	Income Taxes Our results are included in the CenturyLink consolidated federal income tax return and certain combined state income tax returns. CenturyLink allocates income tax expense to us based upon a separate return allocation method which results in income tax expense that approximates the expense that would result if we were a stand-alone entity. Our reported deferred tax assets and liabilities, as discussed below and in Note 11—Income Taxes, are primarily determined as a result of the application of the separate return allocation method and therefore the settlement of these amounts is dependent upon our parent, CenturyLink, rather than tax authorities. Our current expectation is that the vast majority of deferred tax assets and liabilities will be settled through our general intercompany obligation based upon the current CenturyLink policy. CenturyLink has the right to change their policy regarding settlement of these assets and liabilities at any time. The provision for income taxes consists of an amount for taxes currently payable, an amount for tax consequences deferred to future periods and adjustments to our liabilities for uncertain tax positions. We record deferred income tax assets and liabilities reflecting future tax consequences attributable to differences between the financial statement carrying value of assets and liabilities and the tax bases of those assets and liabilities. Deferred taxes are computed using enacted tax rates expected to apply in the year in which the differences are expected to affect taxable income. The effect on deferred income tax assets and liabilities of a change in tax rate is recognized in earnings in the period that includes the enactment date. We establish valuation allowances when necessary to reduce deferred income tax assets to the amounts that we believe are more likely than not to be recovered. Each quarter we evaluate the need to retain all or a portion of the valuation allowance on our deferred tax assets. See Note 11—Income Taxes for additional information.
Cash and Cash Equivalents	Cash and Cash Equivalents Cash and cash equivalents include highly liquid investments that are readily convertible into cash and are not subject to significant risk from fluctuations in interest rates. As a result, the value at which cash and cash equivalents are reported in our consolidated financial statements approximates their fair value. Our cash collections are transferred to CenturyLink on a daily basis and our ultimate parent funds our cash disbursement needs. The net cash transferred to CenturyLink has been reflected as advances to affiliates in our consolidated balance sheets.
Accounts Receivable and Allowance for Doubtful Accounts	Accounts Receivable and Allowance for Doubtful Accounts Accounts receivable are recognized based upon the amount due from customers for the services provided or at cost for purchased and other receivables less an allowance for doubtful accounts. The allowance for doubtful accounts receivable reflects our best estimate of probable losses inherent in our receivable portfolio determined on the basis of historical experience, specific allowances for known troubled accounts and other currently available evidence. We generally consider our accounts past due if they are outstanding over 30 days. Our collection process varies by the customer segment, amount of the receivable, and our evaluation of the customer's credit risk. Our past due accounts are written off against our allowance for doubtful accounts when collection is considered to be not probable. Any recoveries of accounts previously written off are generally recognized as a reduction in bad debt expense in the period received. The carrying value of accounts receivable, net of the allowance for doubtful accounts, approximates fair value.
Property, Plant and Equipment	Property, Plant and Equipment As a result of our indirect acquisition by CenturyLink, property, plant and equipment acquired at the time of acquisition was recorded based on its estimated fair value as of the acquisition date. Subsequently purchased and constructed property, plant and equipment are recorded at cost. Property, plant and equipment is depreciated primarily using the straight-line group method. Under the straight-line group method, assets dedicated to providing telecommunications services (which comprise the majority of our property, plant and equipment) that have similar physical characteristics, use and expected useful lives are pooled for purposes of depreciation and tracking. The equal life group procedure is used to establish each pool's average remaining useful life. Generally, under the straight-line group method, when an asset is sold or retired in the course of normal business activities, the cost is deducted from property, plant and equipment and charged to accumulated depreciation without recognition of a gain or loss. A gain or loss is recognized in our consolidated statements of operations only if a disposal is unusual. Leasehold improvements are amortized over the shorter of the useful lives of the assets or the expected lease term. Expenditures for maintenance and repairs are expensed as incurred. Interest is capitalized during the construction phase of network and other internal-use capital projects. Employee-related costs for construction of network and other internal use assets are also capitalized during the construction phase. Property, plant and equipment supplies used internally are carried at average cost, except for significant individual items for which cost is based on specific identification. We perform annual internal reviews to evaluate the reasonableness of the depreciable lives for our property, plant and equipment. Our reviews utilize models that take into account actual usage, physical wear and tear, replacement history, assumptions about technology evolution and, in certain instances, actuarially determined probabilities to estimate the remaining useful life of our asset base. Our remaining useful life assessments anticipate the loss in service value of assets that may precede the physical retirement. Assets shared among many customers may lose service value as those customers leave the network. However, the asset is not retired until all customers no longer utilize the asset and we determine there is no alternative use for the asset. We review long-lived tangible assets for impairment whenever facts and circumstances indicate that the carrying amounts of the assets may not be recoverable. For assessment purposes, long-lived assets are grouped with other assets and liabilities at the lowest level for which identifiable cash flows are largely independent of the cash flows of other assets and liabilities, absent a material change in operations. An impairment loss is recognized only if the carrying amount of the asset group is not recoverable and exceeds its fair value. Recoverability of the asset group to be held and used is assessed by comparing the carrying amount of the asset group to the estimated undiscounted future net cash flows expected to be generated by the asset group. If the asset group's carrying value is not recoverable, an impairment charge is recognized for the amount by which the carrying amount of the asset group exceeds its fair value. We determine fair values by using a combination of comparable market values and discounted cash flows, as appropriate.
Goodwill, Customer Relationships and Other Intangible Assets	Goodwill, Customer Relationships and Other Intangible Assets Intangible assets arising from business combinations, such as goodwill, customer relationships and capitalized software are initially recorded at estimated fair value. We amortize customer relationships primarily over an estimated life of ten years, using either the sum-of-the-years-digits or the straight-line methods, depending on the type of customer. We amortize capitalized software using the straight-line method over estimated lives ranging up to seven years. Other intangible assets not arising from business combinations are initially recorded at cost. Internally used software, whether purchased or developed by us, is capitalized and amortized using the straight-line method over its estimated useful life. We have capitalized certain costs associated with software such as costs of employees devoting time to the projects and external direct costs for materials and services. Costs associated with software to be used for internal purposes are expensed until the point at which the project has reached the development stage. Subsequent additions, modifications or upgrades to internal-use software are capitalized only to the extent that they allow the software to perform a task it previously did not perform. Software maintenance, data conversion and training costs are expensed in the period in which they are incurred. We review the remaining economic lives of our capitalized software annually. Capitalized software is included in other intangible assets, net, in our consolidated balance sheets. We are required to assess goodwill for impairment at least annually, or more frequently, if an event occurs or circumstances change that would indicate an impairment may have occurred. We are required to write-down the value of goodwill in periods in which the recorded amount of goodwill exceeds the implied fair value of goodwill. The impairment assessment is performed annually at the reporting unit level. We have determined that our operations consist of one reporting unit, consistent with our determination that our business consists of one operating segment. See Note 2—Goodwill, Customer Relationships and Other Intangible Assets for additional information.
Pension and Post-Retirement Benefits	Pension and Post-Retirement Benefits A substantial portion of our active and retired employees participate in the CenturyLink Combined Pension Plan. On December 31, 2014, the QCII pension plan and a pension plan of an affiliate were merged into the CenturyLink Retirement Plan. The CenturyLink Retirement Plan was renamed the CenturyLink Combined Pension Plan. Prior to the pension plan merger, the above-noted employees participated in the QCII pension plan. In addition, certain of our employees participate in CenturyLink's post-retirement health care and life insurance benefit plans. CenturyLink allocates service costs relating to pension and post-retirement health care and life insurance benefits to us and its other affiliates. The amounts contributed by us through CenturyLink are not segregated or restricted to pay amounts due to our employees and may be used to provide benefits to other employees of CenturyLink. The allocation of the service costs to us is based upon our employees who are currently earning benefits under the plans. For further information on qualified pension, post-retirement and other post-employment benefit plans, see CenturyLink's annual report on Form 10-K for the year ended December 31, 2017.
Recent Accounting Pronouncements	Recent Accounting Pronouncements Goodwill Impairment On January 26, 2017, The Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update ("ASU") ASU 2017-04, “Simplifying the Test for Goodwill Impairment” (“ASU 2017-04”). ASU 2017-04 simplifies the impairment testing for goodwill by changing the measurement for goodwill impairment. Under current rules, we are required to compute the implied fair value of goodwill to measure the impairment amount if the carrying value of a reporting unit exceeds its fair value. Under ASU 2017-04, the goodwill impairment charge will equal the excess of the reporting unit carrying value above fair value, limited to the amount of goodwill assigned to the reporting unit. We are required to adopt the provisions of ASU 2017-04 for any goodwill impairment tests, including our required annual test, occurring after January 1, 2020, but have the option to early adopt for any impairment test that we are required to perform. We have not determined if we will elect to early adopt the provisions of ASU 2017-04. The provisions of ASU 2017-04 would not have affected our last goodwill impairment assessment, but no assurance can be provided that the simplified testing methodology will not affect our goodwill impairment assessment in the future. Income Taxes On October 24, 2016, the FASB issued ASU 2016-16, “Intra-Entity Transfers of Assets Other Than Inventory” ("ASU 2016-16"). ASU 2016-16 eliminates the current prohibition on the recognition of the income tax effects on the transfer of assets among our subsidiaries. After adoption of this ASU, the income tax effects associated with these asset transfers, except for the transfer of inventory, will be recognized in the period the asset is transferred versus the current deferral and recognition upon either the sale of the asset to a third party or over the remaining useful life of the asset. We plan to adopt the provisions of ASU 2016-16 on January 1, 2018. The adoption of ASU 2016-16 is not expected to have a material impact to our consolidated financial statements. Financial Instruments On June 16, 2016, the FASB issued ASU 2016-13, “Measurement of Credit Losses on Financial Instruments” (“ASU 2016-13”). The primary impact of ASU 2016-13 for us is a change in the model for the recognition of credit losses related to our financial instruments from an incurred loss model, which recognized credit losses only if it was probable that a loss had been incurred, to an expected loss model, which requires our management team to estimate the total credit losses expected on the portfolio of financial instruments. We are currently reviewing the requirements of the standard and evaluating the impact on our consolidated financial statements. We are required to adopt the provisions of ASU 2016-13 effective January 1, 2020, but could elect to early adopt the provisions as of January 1, 2019. We expect to recognize the impacts of adopting ASU 2016-13 through a cumulative adjustment to retained earnings as of the date of adoption. As of the date of this report, we have not yet determined the date we will adopt ASU 2016-13. Leases On February 25, 2016, the FASB issued ASU 2016-02, “Leases” (“ASU 2016-02”). The core principle of ASU 2016-02 will require lessees to present right-of-use assets and lease liabilities on their balance sheets for operating leases, which are currently not reflected on their balance sheets. ASU 2016-02 is effective for annual and interim periods beginning January 1, 2019. Early adoption of ASU 2016-02 is permitted. Upon adoption of ASU 2016-02, we are required to recognize and measure leases at the beginning of the earliest period presented in our consolidated financial statements using a modified retrospective approach. The modified retrospective approach includes a number of optional practical expedients that we may elect to apply. We have completed our initial assessment of our business and system requirements and we are currently developing and implementing a new lease accounting and administrative system to comply with the requirements of ASU 2016-02. We plan to adopt the standard when it becomes effective for us beginning January 1, 2019 and the adoption of the standard will result in the recognition of right of use assets and lease liabilities that have not previously been recorded. Although we believe it is premature as of the date of this report to provide any estimate of the impact of adopting ASU 2016-02, we do expect that it will have a material impact on our consolidated financial statements. Revenue Recognition On May 28, 2014, the FASB issued ASU 2014-09, “Revenue from Contracts with Customers” (“ASU 2014-09”). ASU 2014-09 replaces virtually all existing generally accepted accounting principles (“GAAP”) on revenue recognition and replaces them with a principles-based approach for determining revenue recognition using a new five step model. The core principle of ASU 2014-09 is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. ASU 2014-09 also includes new accounting principles related to the deferral and amortization of contract acquisition and fulfillment costs. On July 9, 2015, the FASB approved the deferral of the effective date of ASU 2014-09 by one year until January 1, 2018, which is the date we plan to adopt this standard. ASU 2014-09 may be adopted by applying the provisions of this standard on a retrospective basis to the periods included in the financial statements or on a modified retrospective basis which would result in the recognition of a cumulative effect of adopting ASU 2014-09 in the first quarter of 2018. We plan to adopt the new revenue recognition standard under the modified retrospective transition method. The most significant judgments and impacts upon adoption of the standard include the following items: Upon adoption, we will defer (i.e. capitalize) incremental contract acquisition costs and recognize (i.e. amortize) them over the term of the initial contract and anticipated renewal contracts to which the costs relate. Our deferred contract costs for our business and consumer customers have average amortization periods of approximately 49 months and 30 months, respectively, and are subject to being monitored every period to reflect any significant change in assumptions. In addition, we will assess our deferred contract cost asset for impairment on a periodic basis. Promotional bill credits, discounts and prepaid cards offered to customers as part of renewing services or entering into a new services arrangement that are paid over time and are contingent on the customer maintaining a service contract results in an extended service contract term with multiple performance obligations, which impacts the allocation and timing of revenue recognition between service revenue and revenue assigned to the customer credits. A contract asset will be recorded when services are delivered to the customer, and subsequently recognized as a reduction to service revenue over the extended contract term. We are in the process of implementing a new revenue accounting system, as well as, new processes and internal controls over revenue recognition to assist us in the application of the new standard. The cumulative effect of initially applying the new revenue standard on January 1, 2018 is estimated to be an increase to retained earnings of approximately $150 million to $300 million.

Goodwill, Customer Relationships and Other Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2017

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of goodwill, customer relationships and other intangible assets

Goodwill, customer relationships and other intangible assets consisted of the following:



	As of December 31,
	2017		2016
	(Dollars in millions)
Goodwill	$	9,360	9,354
Customer relationships, less accumulated amortization of $4,337 and $3,822	$	1,362	1,877
Other intangible assets subject to amortization:
Capitalized software, less accumulated amortization of $1,619 and $1,510	$	379	471

Summary of amortization expense

Total amortization expense for intangible assets was as follows:



	Years Ended December 31,
	2017		2016	2015
	(Dollars in millions)
Amortization expense for intangible assets	$	671	767	871

Schedule of estimated amortization expense for intangible assets

We estimate that total amortization expense for intangible assets for the years ending December 31, 2018 through 2022 will be as follows:



	(Dollars in millions)
Year ending December 31,
2018	$	583
2019	513
2020	446
2021	136
2022	32

Long-Term Debt and Revolving Promissory Note (Tables)

12 Months Ended

Dec. 31, 2017

Debt Disclosure [Abstract]

Schedule of long-term debt, including unamortized discounts and premiums

Long-term debt, including unamortized premiums and discounts, unamortized debt issuance costs and note payable-affiliate, were as follows:



			As of December 31,
	Interest Rates	Maturities	2017			2016
			(Dollars in millions)
Senior notes	6.125% - 7.750%	2021 - 2057	$	7,294		7,259
Term loan	3.570%	2025	100			100
Capital lease and other obligations	Various	Various	36			32
Unamortized premiums, net			1			4
Unamortized debt issuance costs			(150		)	(134	)
Total long-term debt			7,281			7,261
Less current maturities			(17		)	(514	)
Long-term debt, excluding current maturities			$	7,264		6,747
Note payable-affiliate	6.710%	2022	$	965		914

Schedule of aggregate maturities of the entity's long-term debt (excluding unamortized premiums, discounts, and other)

Set forth below is the aggregate principal amount of our long-term debt (excluding unamortized premiums and discounts and unamortized debt issuance costs and other and excluding note payable-affiliate) maturing during the following years:



	(Dollars in millions)⁽¹⁾
2018	$	17
2019	10
2020	5
2021	951
2022	1
2023 and thereafter	6,446
Total long-term debt	$	7,430

_______________________________________________________________________________

⁽¹⁾Actual principal paid in any year may differ due to the possible future refinancing of outstanding debt or the issuance of new debt.

Schedule of amount of gross interest expense, net of capitalized interest and interest expense (income)-affiliates

Interest expense includes interest on total long-term debt. The following table presents the amount of gross interest expense, net of capitalized interest and interest expense-affiliates, net:



	Years Ended December 31,
	2017			2016		2015
	(Dollars in millions)
Interest expense:
Gross interest expense	$	497		497		491
Capitalized interest	(32		)	(19	)	(18	)
Total interest expense	$	465		478		473
Interest expense-affiliates, net	$	63		59		53

- Definition

Tabular disclosure of long-debt instruments or arrangements, including identification, terms, features, collateral requirements and other information necessary to a fair presentation. These are debt arrangements that originally required repayment more than twelve months after issuance or greater than the normal operating cycle of the entity, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=84159872&loc=d3e21475-112644

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(e),(f))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=64930739&loc=d3e28878-108400

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=84159872&loc=d3e21538-112644

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=84159872&loc=d3e21506-112644

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28541-108399

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=84159872&loc=d3e21521-112644

+ Details

Accounts Receivable (Tables)

12 Months Ended

Dec. 31, 2017

Receivables [Abstract]

Schedule of the entity's accounts receivable balances

The following table presents details of our accounts receivable balances:



	As of December 31,
	2017			2016
	(Dollars in millions)
Trade and purchased receivables	$	591		634
Earned and unbilled receivables	99			115
Other	3			4
Total accounts receivable	693			753
Less: allowance for doubtful accounts	(47		)	(53	)
Accounts receivable, less allowance	$	646		700

Schedule of the entity's allowance for doubtful accounts

The following table presents details of our allowance for doubtful accounts:



	Beginning Balance		Additions	Deductions		Ending Balance
	(Dollars in millions)
2017	$	53	74	(80	)	47
2016	$	47	80	(74	)	53
2015	$	38	78	(69	)	47

Property, Plant and Equipment (Tables)

12 Months Ended

Dec. 31, 2017

Property, Plant and Equipment [Abstract]

Schedule of net property, plant and equipment

Net property, plant and equipment is composed of the following:



	Depreciable Lives	As of December 31,
	Depreciable Lives	2017			2016
		(Dollars in millions)
Property, plant and equipment:
Land	N/A	$	333		348
Fiber, conduit and other outside plant⁽¹⁾	15-45 years	6,639			5,980
Central office and other network electronics⁽²⁾	4-10 years	4,250			3,855
Support assets⁽³⁾	5-30 years	2,620			2,633
Construction in progress⁽⁴⁾	N/A	474			431
Gross property, plant and equipment		14,316			13,247
Accumulated depreciation		(6,392		)	(5,602	)
Net property, plant and equipment		$	7,924		7,645

_______________________________________________________________________________


⁽¹⁾	Fiber, conduit and other outside plant consists of fiber and metallic cable, conduit, poles and other supporting structures.


⁽²⁾	Central office and other network electronics consists of circuit and packet switches, routers, transmission electronics and electronics providing service to customers.


⁽³⁾	Support assets consist of buildings, computers and other administrative and support equipment.


⁽⁴⁾	Construction in progress includes inventory held for construction and property of the aforementioned categories that has not been placed in service as it is still under construction.

Severance (Tables)

12 Months Ended

Dec. 31, 2017

Restructuring and Related Activities [Abstract]

Schedule of changes in accrued liability for severance expenses

Changes in our accrued liability for severance expenses were as follows:



	Severance
	(Dollars in millions)
Balance at December 31, 2015	$	6
Accrued to expense	89
Payments, net	(43		)
Balance at December 31, 2016	52
Accrued to expense	14
Payments, net	(58		)
Balance at December 31, 2017	$	8

Products and Services Revenues (Tables)

12 Months Ended

Dec. 31, 2017

Segment Reporting [Abstract]

Schedule of operating revenues by products and services

Our operating revenues for our products and services consisted of the following categories for the years ended December 31, 2017, 2016 and 2015:



	Years Ended December 31,
	2017		2016	2015
	(Dollars in millions)
Strategic services	$	2,686	2,696	2,617
Legacy services	2,831		3,216	3,593
Affiliates and other services	3,033		2,998	2,754
Total operating revenues	$	8,550	8,910	8,964

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2017

Income Tax Disclosure [Abstract]

Schedule of components of the income tax expense from continuing operations

The components of the income tax expense from continuing operations are as follows:



	Years Ended December 31,
	2017			2016		2015
	(Dollars in millions)
Income tax expense:
Current:
Federal and foreign	$	777		686		734
State and local	130			115		114
Total current	907			801		848
Deferred:
Federal and foreign	(736		)	(103	)	(170	)
State and local	(37		)	(20	)	(19	)
Total deferred	(773		)	(123	)	(189	)
Income tax expense	$	134		678		659

Schedule of effective income tax rate for continuing operations that differs from the statutory tax rate

The effective income tax rate for continuing operations differs from the statutory tax rate as follows:



	Years Ended December 31,
	2017		2016		2015
	(in percent)
Effective income tax rate:
Federal statutory income tax rate	35.0	%	35.0	%	35.0	%
State income taxes-net of federal effect	3.4	%	3.5	%	3.6	%
Tax reform	(31.0	)%	—	%	—	%
Other	0.1	%	—	%	(0.6	)%
Effective income tax rate	7.5	%	38.5	%	38.0	%

Schedule of components of the deferred tax assets and liabilities

The tax effects of temporary differences that gave rise to significant portions of the deferred tax assets and deferred tax liabilities were as follows:



	As of December 31,
	2017			2016
	(Dollars in millions)
Deferred tax assets and liabilities:
Deferred tax liabilities:
Property, plant and equipment	$	(933	)	(1,384	)
Intangibles assets	(553		)	(1,088	)
Receivable from an affiliate due to pension plan participation	—			(452	)
Total deferred tax liabilities	(1,486		)	(2,924	)
Deferred tax assets:
Payable to affiliate due to post-retirement benefit plan participation	366			954
Other	127			209
Gross deferred tax assets	493			1,163
Less valuation allowance on deferred tax assets	(8		)	(12	)
Net deferred tax assets	485			1,151
Net deferred tax liabilities	$	(1,001	)	(1,773	)

Fair Value Disclosure (Tables)

12 Months Ended

Dec. 31, 2017

Fair Value Disclosures [Abstract]

Schedule of the three input levels in the hierarchy of fair value measurements

The three input levels in the hierarchy of fair value measurements are defined by the FASB generally as follows:



Input Level		Description of Input

Level 1		Observable inputs such as quoted market prices in active markets.
Level 2		Inputs other than quoted prices in active markets that are either directly or indirectly observable.
Level 3		Unobservable inputs in which little or no market data exists.

Schedule of carrying amounts and estimated fair values of long-term debt, excluding capital lease obligations, and input levels to determine fair values

The following table presents the carrying amounts and estimated fair values of our long-term debt, excluding capital lease and other obligations, as well as the input levels used to determine the fair values:



		As of December 31, 2017			As of December 31, 2016
	Input Level	Carrying Amount		Fair Value	Carrying Amount	Fair Value
		(Dollars in millions)
Liabilities-Long-term debt (excluding capital lease and other obligations)	2	$	7,245	7,080	7,229	7,203

Stockholder's Equity (Tables)

12 Months Ended

Dec. 31, 2017

Stockholders' Equity Note [Abstract]

Schedule of cash dividends declared

We declared the following cash dividend to QSC:



	Years Ended December 31,
	2017		2016	2015
	(Dollars in millions)
Cash dividend declared to QSC	$	1,000	1,300	1,350
Cash dividend paid to QSC	1,000		1,300	1,350

Quarterly Financial Data (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2017

Quarterly Financial Information Disclosure [Abstract]

Schedule of quarterly financial information



	First Quarter		Second Quarter	Third Quarter	Fourth Quarter		Total
	(Dollars in millions)
2017
Operating revenues	$	2,162	2,133	2,141	2,114		8,550
Operating income	580		573	560	600		2,313
Income tax expense (benefit)	174		170	168	(378	)	134
Net income	278		268	265	846		1,657



	First Quarter		Second Quarter	Third Quarter	Fourth Quarter	Total
	(Dollars in millions)
2016
Operating revenues	$	2,253	2,223	2,226	2,208	8,910
Operating income	625		602	576	521	2,324
Income tax expense	188		179	159	152	678
Net income	304		288	255	238	1,085

Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2017

Commitments and Contingencies Disclosure [Abstract]

Summary of the entity's capital lease activity

The tables below summarize our capital lease activity:



	Years Ended December 31,
	2017		2016	2015
	(Dollars in millions)
Assets acquired through capital leases	$	19	10	10
Depreciation expense	9		5	19
Cash payments towards capital leases	8		6	20



	As of December 31,
	2017		2016
	(Dollars in millions)
Assets included in property, plant and equipment	$	57	40
Accumulated depreciation	24		22

Schedule of future annual minimum payments under capital lease

The future annual minimum payments under capital lease arrangements as of December 31, 2017 were as follows:



	Future Minimum Payments
	(Dollars in millions)
Capital lease obligations:
2018	$	14
2019	10
2020	6
2021	2
2022	1
2023 and thereafter	3
Total minimum payments	36
Less: amount representing interest and executory costs	(6		)
Present value of minimum payments	30
Less: current portion	(12		)
Long-term portion	$	18

Schedule of future minimum payments under operating leases

At December 31, 2017, our future rental commitments for operating leases were as follows:



	Future Minimum Payments
	(Dollars in millions)
Operating leases:
2018	$	36
2019	31
2020	24
2021	22
2022	18
2023 and thereafter	46
Total future minimum payments⁽¹⁾	$	177

_______________________________________________________________________________


⁽¹⁾	Minimum payments have not been reduced by minimum sublease rentals of $22 million due in the future under non-cancelable subleases.

Other Financial Information (Tables)

12 Months Ended

Dec. 31, 2017

Additional Financial Information Disclosure [Abstract]

Schedule of other current assets

The following table presents details of other current assets in our consolidated balance sheets:



	As of December 31,
	2017		2016
	(Dollars in millions)
Prepaid expenses	$	42	48
Assets held for sale	—		8
Other	56		73
Total other current assets	$	98	129

Schedule of accounts payable and accrued liabilities

Current liabilities reflected in our consolidated balance sheets include accounts payable:

Basis of Presentation and Summary of Significant Accounting Policies (Details) $ in Millions		12 Months Ended
	Jan. 01, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Deferred Revenue Arrangement [Line Items]
Number of states in which entity operates		14
Advertising Costs
Advertising expense		$ 139	$ 91	$ 84
Accounts Receivable and Allowance for Doubtful Accounts
Threshold for determining accounts receivable as past due, days outstanding		30 days
Activation and installation charges \| Minimum
Revenue Recognition
Customer relationship period for revenue recognition		3 years
Activation and installation charges \| Maximum
Revenue Recognition
Customer relationship period for revenue recognition		7 years
Qwest Communications International, Inc.
Affiliate Transactions
Description of related party transaction				In 2015, we agreed to a plan to settle the outstanding affiliate obligations, net balance with QCII over a 30 year term. Under the plan, payments are scheduled to be made on a monthly basis.
Pension, Supplemental and Other Postretirement Benefit Plans \| Qwest Communications International, Inc.
Affiliate Transactions
Description of related party transaction				In 2015, we agreed to a plan to settle the outstanding pension and post-retirement affiliate obligations, net balance with QCII over a 30 year term. Under the plan, payments are scheduled to be made on a monthly basis.
Repayments on affiliate obligation		$ 87	$ 97
Forecast \| Minimum \| Accounting Standards Update 2014-09
Deferred Revenue Arrangement [Line Items]
Cumulative effect on retained earnings, before tax	$ 150
Forecast \| Maximum \| Accounting Standards Update 2014-09
Deferred Revenue Arrangement [Line Items]
Cumulative effect on retained earnings, before tax	$ 300

Basis of Presentation and Summary of Significant Accounting Policies (Details 2)		12 Months Ended
	Oct. 31, 2017	Dec. 31, 2017 segment
Goodwill, Customer Relationships and Other Intangible Assets
Number of reporting units	1	1
Number of operating segments		1
Customer relationships
Goodwill, Customer Relationships and Other Intangible Assets
Finite-lived intangible assets, maximum useful life		10 years
Capitalized software
Goodwill, Customer Relationships and Other Intangible Assets
Finite-lived intangible assets, maximum useful life		7 years

Goodwill, Customer Relationships and Other Intangible Assets (Details) $ in Millions		12 Months Ended
	Oct. 31, 2017	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Finite-Lived Intangible Assets [Line Items]
Goodwill		$ 9,360	$ 9,354
Gross carrying amounts of goodwill, customer relationships and other intangible assets		17,057
Amortization expense for intangible assets		$ 671	767	$ 871
Number of reporting units	1	1
Estimated amortization expense for intangible assets
2018		$ 583
2019		513
2020		446
2021		136
2022		32
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, net		1,362	1,877
Accumulated amortization		4,337	3,822
Capitalized software
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, net		379	471
Accumulated amortization		$ 1,619	$ 1,510

Long-Term Debt and Revolving Promissory Note (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Apr. 18, 2012
Long-term debt
Long-term debt, gross	$ 7,430
Capital lease and other obligations	36	$ 32
Unamortized premiums, net	1	4
Unamortized debt issuance costs	(150)	(134)
Total long-term debt	7,281	7,261
Less current maturities	(17)	(514)
Long-term debt, excluding current maturities	7,264	6,747
Revolving promissory note
Note payable - affiliate	965	914
Qwest Corporation \| Senior notes
Long-term debt
Long-term debt, gross	$ 7,294	7,259
Qwest Corporation \| Senior notes \| Minimum
Long-term debt
Interest rate, stated percentage (as a percent)	6.125%
Qwest Corporation \| Senior notes \| Maximum
Long-term debt
Interest rate, stated percentage (as a percent)	7.75%
Qwest Corporation \| Term loan
Long-term debt
Long-term debt, gross	$ 100	100
Interest rate, stated percentage (as a percent)	3.57%
Qwest Corporation \| Revolving promissory note \| CenturyLink, Inc. affiliate
Revolving promissory note
Short-term debt, weighted average interest rate (as a percent)	6.71%
Note payable - affiliate	$ 965	$ 914
Maximum borrowing capacity, note payable-affiliate			$ 1,000
Accrued interest payable. note payable-affiliate	$ 16

Long-Term Debt and Revolving Promissory Note (Details 2) $ in Millions								12 Months Ended
	May 05, 2017 USD ($)	Apr. 28, 2017 USD ($)	Sep. 15, 2016 USD ($)	Aug. 29, 2016 USD ($)	Aug. 22, 2016 USD ($)	Jan. 29, 2016 USD ($)	Feb. 20, 2015 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Sep. 30, 2017 USD ($)	May 08, 2017 USD ($)	May 04, 2017 USD ($)	May 02, 2016 USD ($)
Debt instruments
Net loss on early retirement of debt								$ 5	$ 27	$ 0
Long-term debt, gross								7,430
Amount of gross interest expense, net of capitalized interest and interest expense - affiliates
Gross interest expense								497	497	491
Capitalized interest								(32)	(19)	(18)
Total interest expense								465	478	473
Interest expense-affiliates, net								63	59	$ 53
Qwest Corporation \| Senior notes
Debt instruments
Long-term debt, gross								$ 7,294	7,259
Qwest Corporation \| Senior notes \| Minimum
Debt instruments
Interest rate, stated percentage (as a percent)								6.125%
Qwest Corporation \| Senior notes \| Maximum
Debt instruments
Interest rate, stated percentage (as a percent)								7.75%
Qwest Corporation \| Term loan
Debt instruments
Interest rate, stated percentage (as a percent)								3.57%
Long-term debt, gross								$ 100	100
Qwest Corporation \| 6.75% Notes due 2057 \| Senior notes
Debt instruments
Face amount of debt instrument	$ 85	$ 575
Interest rate, stated percentage (as a percent)		6.75%
Net proceeds from issuance of debt	$ 638
Qwest Corporation \| 6.75% Notes due 2057 \| Senior notes \| Debt instrument, redemption period one
Debt instruments
Debt instrument redemption description		redeemed by Qwest Corporation, in whole or in part, on or after June 15, 2022, at a redemption price equal to 100% of the principal amount
Qwest Corporation \| 6.5% Notes due 2056 \| Senior notes
Debt instruments
Face amount of debt instrument					$ 978
Interest rate, stated percentage (as a percent)					6.50%
Debt instrument face amount over-allotment					$ 128
Net proceeds from issuance of debt					$ 946
Qwest Corporation \| 6.5% Notes due 2056 \| Senior notes \| Debt instrument, redemption period one
Debt instruments
Debt instrument redemption description					on or after September 1, 2021, at a redemption price equal to 100% of the principal amount redeemed
Qwest Corporation \| 7.00% Notes due 2056 \| Senior notes
Debt instruments
Face amount of debt instrument						$ 235
Interest rate, stated percentage (as a percent)						7.00%
Net proceeds from issuance of debt						$ 227
Qwest Corporation \| 7.00% Notes due 2056 \| Senior notes \| Debt instrument, redemption period one
Debt instruments
Debt instrument redemption description						on or after February 1, 2021, at a redemption price equal to 100% of the principal amount redeemed
Qwest Corporation \| 7.5% Notes due 2051 \| Senior notes
Debt instruments
Face amount of debt instrument												$ 288
Interest rate, stated percentage (as a percent)			7.50%									7.50%
Repurchased face amount of Senior notes			$ 287									$ 125
Net loss on early retirement of debt			$ 9
Qwest Corporation \| 6.5% Notes due 2017 \| Senior notes
Debt instruments
Interest rate, stated percentage (as a percent)													6.50%
Repurchased face amount of Senior notes													$ 500
Qwest Corporation \| 7.375% Notes due 2051 \| Senior notes
Debt instruments
Interest rate, stated percentage (as a percent)				7.375%
Repurchased face amount of Senior notes				$ 661
Net loss on early retirement of debt				$ 18
Qwest Corporation \| 8.375% Notes due 2016 \| Senior notes
Debt instruments
Interest rate, stated percentage (as a percent)														8.375%
Repurchased face amount of Senior notes														$ 235
Qwest Corporation \| Term Loan \| Term loan
Debt instruments
Face amount of debt instrument							$ 100
Long-term debt, gross								$ 100	$ 100
Term Loan covenant Debt to EBITDA Ratio								2.85
Qwest Corporation \| Term Loan \| Term loan \| Minimum \| London Interbank Offered Rate (LIBOR)
Debt instruments
Interest rate margin (as a percent)							1.50%
Qwest Corporation \| Term Loan \| Term loan \| Minimum \| Base Rate
Debt instruments
Interest rate margin (as a percent)							0.50%
Qwest Corporation \| Term Loan \| Term loan \| Maximum \| London Interbank Offered Rate (LIBOR)
Debt instruments
Interest rate margin (as a percent)							2.50%
Qwest Corporation \| Term Loan \| Term loan \| Maximum \| Base Rate
Debt instruments
Interest rate margin (as a percent)							1.50%
CenturyLink, Inc. affiliate \| Qwest Corporation \| Revolving promissory note
Debt instruments
Face amount of debt instrument											$ 965

Long-Term Debt and Revolving Promissory Note (Details 3) $ in Millions	Dec. 31, 2017 USD ($)
Maturities of long-term debt (excluding unamortized premiums and discounts and unamortized debt issuance costs and other and excluding note payable-affiliate)
2018	$ 17
2019	10
2020	5
2021	951
2022	1
2023 and thereafter	6,446
Total long-term debt	$ 7,430

Accounts Receivable (Details) - USD ($)	12 Months Ended
Accounts Receivable (Details) - USD ($)	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2017	Dec. 31, 2016
Accounts receivable
Other				$ 3,000,000	$ 4,000,000
Total accounts receivable, gross, current				693,000,000	753,000,000
Accounts receivable, allowance (in dollars)	$ (53,000,000)	$ (47,000,000)	$ (38,000,000)	(47,000,000)	(53,000,000)
Accounts receivable, less allowance				646,000,000	700,000,000
Customer receivable in excess of 10% of accounts receivable				0
Changes in allowance for doubtful accounts
Beginning balance	53,000,000	47,000,000	38,000,000
Provision for uncollectible accounts	74,000,000	80,000,000	78,000,000
Deductions	(80,000,000)	(74,000,000)	(69,000,000)
Ending balance	$ 47,000,000	$ 53,000,000	$ 47,000,000
Earned and unbilled receivables
Accounts receivable
Total accounts receivable, gross, current				99,000,000	115,000,000
Trade and purchased receivables
Accounts receivable
Total accounts receivable, gross, current				$ 591,000,000	$ 634,000,000

Property, Plant and Equipment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, plant and equipment
Gross property, plant and equipment	$ 14,316	$ 13,247
Accumulated depreciation	(6,392)	(5,602)
Net property, plant and equipment	7,924	7,645
Depreciation expense	912	924	$ 986
Land
Property, plant and equipment
Gross property, plant and equipment	333	348
Fiber, conduit and other outside plant(1)
Property, plant and equipment
Gross property, plant and equipment	$ 6,639	5,980
Fiber, conduit and other outside plant(1) \| Minimum
Property, plant and equipment
Depreciable lives	15 years
Fiber, conduit and other outside plant(1) \| Maximum
Property, plant and equipment
Depreciable lives	45 years
Central office and other network electronics(2)
Property, plant and equipment
Gross property, plant and equipment	$ 4,250	3,855
Central office and other network electronics(2) \| Minimum
Property, plant and equipment
Depreciable lives	4 years
Central office and other network electronics(2) \| Maximum
Property, plant and equipment
Depreciable lives	10 years
Support assets(3)
Property, plant and equipment
Gross property, plant and equipment	$ 2,620	2,633
Support assets(3) \| Minimum
Property, plant and equipment
Depreciable lives	5 years
Support assets(3) \| Maximum
Property, plant and equipment
Depreciable lives	30 years
Construction in progress(4)
Property, plant and equipment
Gross property, plant and equipment	$ 474	$ 431

Severance (Details) - Employee severance - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Restructuring reserve
Balance at the beginning of the period	$ 52	$ 6
Accrued to expense	14	89
Payments, net	(58)	(43)
Balance at the end of the period	$ 8	$ 52

Employee Benefits (Details)	1 Months Ended	12 Months Ended
Employee Benefits (Details)	Jun. 30, 2017	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Employee Benefits
Collective bargaining agreements term	3 years
Collective bargaining arrangement, number of participating unionized employees			10,000
Collective bargaining arrangement, number of participating active employees and retirees			10,000
Qwest Communications International, Inc.
Employee Benefits
Description of related party transaction					In 2015, we agreed to a plan to settle the outstanding affiliate obligations, net balance with QCII over a 30 year term. Under the plan, payments are scheduled to be made on a monthly basis.
CenturyLink, Inc.
Employee Benefits
Allocated expenses by parent entities (as a percent)			70.00%	70.00%	69.00%
Pension Plan
Employee Benefits
Defined benefit plan, service cost			$ 44,000,000	$ 45,000,000	$ 57,000,000
Pension Plan \| CenturyLink, Inc.
Employee Benefits
Employer contributions to benefit plan			100,000,000	100,000,000
Unfunded status			(2,004,000,000)	(2,352,000,000)
Post-Retirement Benefit Plan
Employee Benefits
Defined benefit plan, service cost			12,000,000	14,000,000	$ 17,000,000
Post-Retirement Benefit Plan \| CenturyLink, Inc.
Employee Benefits
Employer contributions to benefit plan			0	0
Unfunded status			(3,352,000,000)	(3,360,000,000)
Pension, Supplemental and Other Postretirement Benefit Plans \| Qwest Communications International, Inc.
Employee Benefits
Description of related party transaction					In 2015, we agreed to a plan to settle the outstanding pension and post-retirement affiliate obligations, net balance with QCII over a 30 year term. Under the plan, payments are scheduled to be made on a monthly basis.
Repayments on affiliate obligation			$ 87,000,000	$ 97,000,000
Change in accounting method accounted for as change in estimate \| Pension, Supplemental and Other Postretirement Benefit Plans
Employee Benefits
Change in allocation of pension and post-retirement service costs					In 2015, our ultimate parent company, CenturyLink, changed their allocation methodology with respect to their now centrally managed pension and post-retirement plans. Specifically, under this new methodology, CenturyLink will allocate current service costs to subsidiaries relative to employees who are currently earning benefits under the pension and post-retirement benefit plans. The net periodic benefit cost allocated to us is now paid on a monthly basis through CenturyLink’s intercompany cash management process.
Forecast \| Pension Plan \| CenturyLink, Inc.
Employee Benefits
Employer contributions to benefit plan		$ 100,000,000

Employee Benefits (Details 2) - USD ($) $ in Millions	12 Months Ended
Employee Benefits (Details 2) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Health Care and Life Insurance [Abstract]
Health care benefit expenses	$ 204	$ 241	$ 217

Employee Benefits (Details 3) - USD ($) $ in Millions	12 Months Ended
Employee Benefits (Details 3) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Pension Plan
Defined Contribution Plan Disclosure [Line Items]
Costs recognized for 401(k) Plan	$ 42	$ 42	$ 43

Share-Based Compensation (Details) - Stock compensation plan - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based compensation
Share based compensation expense	$ 27	$ 22	$ 21
Income tax benefit recognized, associated with share-based compensation expense	$ 7	$ 8	$ 8

Products and Services Revenues (Details) $ in Millions	3 Months Ended								12 Months Ended
Products and Services Revenues (Details) $ in Millions	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2017 USD ($) category	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Products and Services Revenues
Number of categories of products and services (categories) \| category									3
Operating revenues	$ 2,114	$ 2,141	$ 2,133	$ 2,162	$ 2,208	$ 2,226	$ 2,223	$ 2,253	$ 8,550	$ 8,910	$ 8,964
Taxes and surcharges included in operating revenues and expenses									$ 134	149	147
Number of reportable segments									1
Strategic services
Products and Services Revenues
Operating revenues									$ 2,686	2,696	2,617
Legacy services
Products and Services Revenues
Operating revenues									2,831	3,216	3,593
Affiliates and other services
Products and Services Revenues
Operating revenues									$ 3,033	$ 2,998	$ 2,754

Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
Income Taxes (Details) - USD ($) $ in Millions	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Contingency [Line Items]
Provisional tax benefit, amount	$ 555
Current:
Federal and foreign									$ 777	$ 686	$ 734
State and local									130	115	114
Total current									907	801	848
Deferred:
Federal and foreign									(736)	(103)	(170)
State and local									(37)	(20)	(19)
Total deferred									(773)	(123)	(189)
Income tax expense	$ (378)	$ 168	$ 170	$ 174	$ 152	$ 159	$ 179	$ 188	$ 134	$ 678	$ 659
Effective income tax rate:
Federal statutory income tax rate (as a percent)	35.00%								35.00%	35.00%	35.00%
Federal income tax rate after enactment of Tax Reform (as a percent)	21.00%
State income taxes-net of federal effect (as a percent)									3.40%	3.50%	3.60%
Tax Reform, Percent									(31.00%)	(0.00%)	(0.00%)
Other (as a percent)									0.10%	0.00%	(0.60%)
Effective income tax rate (as a percent)									7.50%	38.50%	38.00%
Deferred tax liabilities:
Property, plant and equipment	$ (933)				(1,384)				$ (933)	$ (1,384)
Intangibles assets	(553)				(1,088)				(553)	(1,088)
Receivable from an affiliate due to pension plan participation	0				(452)				0	(452)
Total deferred tax liabilities	(1,486)				(2,924)				(1,486)	(2,924)
Deferred tax assets:
Payable to affiliate due to post-retirement plan participation	366				954				366	954
Other	127				209				127	209
Gross deferred tax assets	493				1,163				493	1,163
Less valuation allowance on deferred tax assets	(8)				(12)				(8)	(12)
Net deferred tax assets	485				1,151				485	1,151
Net deferred tax liabilities	(1,001)				(1,773)				(1,001)	(1,773)
Change in valuation allowance of deferred tax assets									4
Domestic tax authority
Income Tax Contingency [Line Items]
Liabilities recorded for interest related to uncertain tax positions	0				0				0	0	$ 0
Liabilities recorded for penalties related to uncertain tax positions	$ 0				$ 0				$ 0	$ 0	$ 0

Income Taxes (Details 2) - USD ($) $ in Millions	12 Months Ended
Income Taxes (Details 2) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Qwest Services Corporation
Related Party Transaction [Line Items]
Income taxes paid	$ 907	$ 801	$ 848

Fair Value Disclosure (Details) - Fair value, measurements, nonrecurring - Fair value inputs, Level 2 - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Carrying amount
Liabilities
Liabilities-Long-term debt (excluding capital lease and other obligations)	$ 7,245	$ 7,229
Fair value
Liabilities
Liabilities-Long-term debt (excluding capital lease and other obligations)	$ 7,080	$ 7,203

Stockholder's Equity (Details) - USD ($) $ in Millions		12 Months Ended
Stockholder's Equity (Details) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Stockholder's Equity (Deficit)
Common stock, shares issued (in shares)		1	1
Common stock, shares outstanding (shares)		1	1
Dividend of equity interest in limited liability company to Qwest Services Corporation	$ 12
Dividends
Dividends declared to QSC		$ 1,000	$ 1,300	$ 1,350
Cash dividend paid to QSC		$ 1,000	$ 1,300	$ 1,350
COMMON STOCK
Stockholder's Equity (Deficit)
Common stock, shares issued (in shares)		1
Common stock, shares outstanding (shares)		1

Quarterly Financial Data (Unaudited) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating quarterly financial data
Operating revenues	$ 2,114	$ 2,141	$ 2,133	$ 2,162	$ 2,208	$ 2,226	$ 2,223	$ 2,253	$ 8,550	$ 8,910	$ 8,964
Operating income	600	560	573	580	521	576	602	625	2,313	2,324	2,260
Income tax expense (benefit)	(378)	168	170	174	152	159	179	188	134	678	659
Net income	846	$ 265	$ 268	$ 278	238	$ 255	$ 288	$ 304	$ 1,657	$ 1,085	$ 1,074
Provisional tax benefit, amount	$ 555
Federal statutory income tax rate (as a percent)	35.00%								35.00%	35.00%	35.00%
Federal income tax rate after enactment of Tax Reform (as a percent)	21.00%
Severance costs					$ 78

Commitments and Contingencies Commitments and Contingencies (Details)	12 Months Ended
	Dec. 31, 2017 USD ($) lawsuit
Loss Contingencies [Line Items]
Number of patents allegedly Infringed, minimum	1
Unfavorable regulatory action
Loss Contingencies [Line Items]
Maximum possible loss per proceeding \| $	$ 100,000
Interexchange Carriers
Loss Contingencies [Line Items]
Number of lawsuits (approximately) \| lawsuit	100

Commitments and Contingencies (Details 2) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Leases, Capital
Assets acquired through capital leases	$ 19	$ 10	$ 10
Depreciation expense	9	5	19
Cash payments towards capital leases	8	6	$ 20
Assets included in property, plant and equipment	57	40
Accumulated depreciation	24	$ 22
Capital lease obligations:
2018	14
2019	10
2020	6
2021	2
2022	1
2023 and thereafter	3
Total minimum payments	36
Less: amount representing interest and executory costs	(6)
Present value of minimum payments	30
Less: current portion	(12)
Long-term portion	$ 18

Commitments and Contingencies (Details 3) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Leases, Operating
Operating leases, rent expense	$ 70	$ 72	$ 75
Sublease rental income received	2	$ 4	$ 4
Operating leases:
2018	36
2019	31
2020	24
2021	22
2022	18
2023 and thereafter	46
Total future minimum payments	177
Minimum sublease rentals due in the future under non-cancelable subleases	22
Purchase Obligations
Total purchase commitments	59
2018	48
2019 through 2020	$ 11

Other Financial Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Additional Financial Information Disclosure [Abstract]
Impairment of asset	$ 1	$ 11	$ 0
Prepaid Expense and Other Assets, Current [Abstract]
Prepaid expenses	42	48
Assets held for sale	0	8
Other	56	73
Total other current assets	98	129
Accounts Payable, Current [Abstract]
Accounts payable	317	398
Capital expenditures incurred but not yet paid	$ 86	$ 53

Labor Union Contracts (Details)	12 Months Ended
Labor Union Contracts (Details)	Dec. 31, 2017
Labor Union Contracts
Collective bargaining arrangement, number of participating unionized employees	10,000
Unionized employees concentration risk \| Employees covered under collective bargaining agreements
Labor Union Contracts
Concentration risk, (percent)	45.00%
Workforce subject to collective bargaining arrangements, effective June 18, 2017
Labor Union Contracts
Collective bargaining arrangement, number of participating unionized employees	10,000

As of December 31,

(Dollars in millions)

Accounts payable