Document and Entity Information - USD ($) $ in Billions	12 Months Ended
Document and Entity Information - USD ($) $ in Billions	Dec. 31, 2015	Feb. 17, 2016	Jun. 30, 2015
Document and Entity Information
Entity Registrant Name	CENTURYLINK, INC
Entity Central Index Key	0000018926
Document Type	10-K
Document Period End Date	Dec. 31, 2015
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$ 16.4
Entity Common Stock, Shares Outstanding (shares)		543,852,862
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	FY

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Statement [Abstract]
Operating revenues	$ 17,900	$ 18,031	$ 18,095
OPERATING EXPENSES
Cost of services and products (exclusive of depreciation and amortization)	7,778	7,846	7,507
Selling, general and administrative	3,328	3,347	3,502
Depreciation and amortization	4,189	4,428	4,541
Impairment of goodwill (Note 2)	0	0	1,092
Total operating expenses	15,295	15,621	16,642
OPERATING INCOME	2,605	2,410	1,453
OTHER (EXPENSE) INCOME
Interest expense	(1,312)	(1,311)	(1,298)
Net gain on early retirement of debt	0	0	10
Other income, net	23	11	59
Total other expense, net	(1,289)	(1,300)	(1,229)
INCOME BEFORE INCOME TAX EXPENSE	1,316	1,110	224
Income tax expense	438	338	463
NET INCOME (LOSS)	$ 878	$ 772	$ (239)
BASIC AND DILUTED EARNINGS (LOSS) PER COMMON SHARE
Basic earnings (loss) per common share (in dollars per share)	$ 1.58	$ 1.36	$ (0.40)
Diluted earnings (loss) per common share (in dollars per share)	$ 1.58	$ 1.36	$ (0.40)
WEIGHTED AVERAGE COMMON SHARES OUTSTANDING
BASIC (in shares)	554,278	568,435	600,892
DILUTED (in shares)	555,093	569,739	600,892

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 878	$ 772	$ (239)
Items related to employee benefit plans:
Change in net actuarial gain (loss), net of $(12), $742 and $(606) tax	21	(1,200)	981
Change in net prior service credit (costs), net of $(47), $1 and $52 tax	76	(1)	(84)
Foreign currency translation adjustment and other, net of $-, $1 and $- tax	(14)	(14)	2
Other comprehensive income (loss)	83	(1,215)	899
COMPREHENSIVE INCOME (LOSS)	$ 961	$ (443)	$ 660

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References + Details

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement of Comprehensive Income [Abstract]
Change in net actuarial (loss) gain, tax	$ (12)	$ 742	$ (606)
Change in net prior service credit (costs), tax	(47)	1	52
Foreign currency translation adjustment and other, tax	$ 0	$ 1	$ 0

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
CURRENT ASSETS
Cash and cash equivalents	$ 126	$ 128
Accounts receivable, less allowance of $152 and $162	1,943	1,988
Other	581	580
Total current assets	2,650	2,696
NET PROPERTY, PLANT AND EQUIPMENT
Property, plant and equipment	38,785	36,718
Accumulated depreciation	(20,716)	(18,285)
Net property, plant and equipment	18,069	18,433
GOODWILL AND OTHER ASSETS
Goodwill	20,742	20,755
Other intangible assets, net	1,555	1,647
Other, net	660	679
Total goodwill and other assets	26,885	27,974
TOTAL ASSETS	47,604	49,103
CURRENT LIABILITIES
Current maturities of long-term debt	1,503	550
Accounts payable	968	1,226
Accrued expenses and other liabilities
Salaries and benefits	602	641
Income and other taxes	318	309
Interest	250	256
Other	220	210
Advance billings and customer deposits	743	726
Total current liabilities	4,604	3,918
LONG-TERM DEBT	18,722	19,953
DEFERRED CREDITS AND OTHER LIABILITIES
Deferred income taxes, net	3,569	3,154
Benefit plan obligations, net	5,511	5,808
Other	1,138	1,247
Total deferred credits and other liabilities	$ 10,218	$ 10,209
COMMITMENTS AND CONTINGENCIES (Note 14)
STOCKHOLDERS' EQUITY
Preferred stock — non-redeemable, $25.00 par value, authorized 2,000 shares, issued and outstanding 7 and 7 shares	$ 0	$ 0
Common stock, $1.00 par value, authorized 1,600,000 and 1,600,000 shares, issued and outstanding 543,800 and 568,517 shares	544	569
Additional paid-in capital	15,178	16,324
Accumulated other comprehensive loss	(1,934)	(2,017)
Retained earnings	272	147
Total stockholders' equity	14,060	15,023
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	47,604	49,103
Customer relationships, net
Finite lived intangible assets, net	$ 3,928	$ 4,893

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) shares in Thousands, $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Statement of Financial Position [Abstract]
Accounts receivable, allowance	$ 152	$ 162
Preferred stock-non-redeemable, par value (in dollars per share)	$ 25.00	$ 25.00
Preferred stock-non-redeemable, authorized shares (shares)	2,000	2,000
Preferred stock-non-redeemable, issued shares (shares)	7	7
Preferred stock-non-redeemable, outstanding shares (shares)	7	7
Common stock, par value (in dollars per share)	$ 1.00	$ 1.00
Common stock, authorized shares (shares)	1,600,000	1,600,000
Common stock, issued shares (shares)	543,800	568,517
Common stock, outstanding shares (shares)	543,800	568,517

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
OPERATING ACTIVITIES
Net income (loss)	$ 878	$ 772	$ (239)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	4,189	4,428	4,541
Impairment of goodwill (Note 2)	0	0	1,092
Impairment of assets	9	32	0
Deferred income taxes	350	291	391
Provision for uncollectible accounts	177	159	152
Gain on sale of intangible assets	0	0	(32)
Net long-term debt issuance costs and premium amortization	(3)	(21)	(46)
Net gain on early retirement of debt	0	0	(10)
Share-based compensation	73	79	71
Changes in current assets and liabilities:
Accounts receivable	(132)	(163)	(212)
Accounts payable	(168)	70	(76)
Accrued income and other taxes	32	(84)	28
Other current assets and liabilities, net	(53)	(270)	263
Retirement benefits	(141)	(184)	(342)
Changes in other noncurrent assets and liabilities, net	(78)	99	8
Other, net	19	(20)	(30)
Net cash provided by operating activities	5,152	5,188	5,559
INVESTING ACTIVITIES
Payments for property, plant and equipment and capitalized software	(2,872)	(3,047)	(3,048)
Cash paid for acquisitions	4	93	160
Proceeds from sale of property and intangible assets	31	63	80
Other, net	(8)	0	(20)
Net cash used in investing activities	(2,853)	(3,077)	(3,148)
FINANCING ACTIVITIES
Net proceeds from issuance of long-term debt	989	483	2,481
Repayments of long-term debt	(966)	(800)	(2,010)
Net payments on credit facility and revolving line of credit	(315)	(4)	(95)
Early retirement of debt costs	(1)	0	(31)
Dividends paid	(1,198)	(1,228)	(1,301)
Net proceeds from issuance of common stock	11	50	73
Repurchase of common stock	(819)	(650)	(1,586)
Other, net	(2)	(2)	15
Net cash used in financing activities	(2,301)	(2,151)	(2,454)
Net decrease in cash and cash equivalents	(2)	(40)	(43)
Cash and cash equivalents at beginning of period	128	168	211
Cash and cash equivalents at end of period	126	128	168
Supplemental cash flow information:
Income taxes paid, net	(63)	(27)	(48)
Interest paid (net of capitalized interest of $52, $47 and $41)	$ (1,310)	$ (1,338)	$ (1,333)

CONSOLIDATED STATEMENTS OF CASH FLOWS (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement of Cash Flows [Abstract]
Interest (paid) capitalized interest	$ 52	$ 47	$ 41

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Millions	Total	COMMON STOCK	ADDITIONAL PAID-IN CAPITAL	ACCUMULATED OTHER COMPREHENSIVE LOSS	RETAINED EARNINGS
Balance at beginning of period at Dec. 31, 2012		$ 626	$ 19,079	$ (1,701)	$ 1,285
Increase (Decrease) in Stockholders' Equity
Issuance of common stock through dividend reinvestment, incentive and benefit plans		4	69
Repurchase of common stock		(46)	(1,551)
Shares withheld to satisfy tax withholdings			(18)
Share-based compensation and other, net			85
Other comprehensive income (loss)				899
Dividends declared			(321)		(980)
Net income (loss)	$ (239)				(239)
Balance at end of period at Dec. 31, 2013	17,191	584	17,343	(802)	66
Increase (Decrease) in Stockholders' Equity
Issuance of common stock through dividend reinvestment, incentive and benefit plans		4	46
Repurchase of common stock		(19)	(591)
Shares withheld to satisfy tax withholdings			(16)
Share-based compensation and other, net			82
Other comprehensive income (loss)	(1,215)			(1,215)
Dividends declared			(540)		(691)
Net income (loss)	772				772
Balance at end of period at Dec. 31, 2014	15,023	569	16,324	(2,017)	147
Increase (Decrease) in Stockholders' Equity
Issuance of common stock through dividend reinvestment, incentive and benefit plans		2	9
Repurchase of common stock		(27)	(767)
Shares withheld to satisfy tax withholdings			(19)
Share-based compensation and other, net			77
Other comprehensive income (loss)	83			83
Dividends declared			(446)		(753)
Net income (loss)	878				878
Balance at end of period at Dec. 31, 2015	$ 14,060	$ 544	$ 15,178	$ (1,934)	$ 272

Basis of Presentation and Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2015

Accounting Policies [Abstract]

Basis of Presentation and Summary of Significant Accounting Policies

Basis of Presentation

We are an integrated communications company engaged primarily in providing an array of communications services to our residential and business customers. Our communications services include local and long-distance voice, high-speed Internet, Multi-Protocol Label Switching ("MPLS"), private line (including special access), data integration, Ethernet, colocation, managed hosting (including cloud hosting), network, public access, wireless, video and other ancillary services.

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.

To simplify the overall presentation of our consolidated financial statements, we report immaterial amounts attributable to noncontrolling interests in certain of our subsidiaries as follows: (i) income attributable to noncontrolling interests in other income, net, (ii) equity attributable to noncontrolling interests in additional paid-in capital and (iii) cash flows attributable to noncontrolling interests in other, net financing activities.

We reclassified certain prior period amounts to conform to the current period presentation, including the categorization of our revenues and our segment reporting. See Note 12—Segment Information for additional information. These changes had no impact on total revenues, total operating expenses or net income (loss) for any period.

Connect America Fund Support Payments

In 2015, we accepted funding from the Federal Communications Commission's ("FCC") Connect America Fund ("CAF") of approximately $500 million per year for six years to fund the deployment of voice and high-speed Internet infrastructure for approximately 1.2 million rural households and businesses in 33 states under the CAF Phase 2 high-cost support program. The funding from the CAF Phase 2 support program in these 33 states will substantially supplant funding from the interstate Universal Service Fund ("USF") high-cost program that we previously utilized to support voice services in high-cost rural markets. In September of 2015, we began receiving these support payments from the FCC under the new CAF Phase 2 support program, which included (i) monthly support payments at a higher rate than under the interstate USF support program and (ii) a one-time cumulative catch-up payment representing the incrementally higher funding under the CAF Phase 2 support program over the interstate USF support program for the first seven months of 2015. During 2015, we recorded $215 million more revenue than we would have otherwise recorded during the same period under the interstate USF support program.

Changes in Estimates

As a result of our annual reviews to evaluate the reasonableness of the depreciable lives for our property, plant and equipment, effective January 2014, we changed the estimates of the remaining economic lives of certain switch and circuit network equipment. These changes resulted in a net increase in depreciation expense of approximately $78 million for the year ended December 31, 2014. This net increase in depreciation expense, net of tax, reduced consolidated net income by approximately $48 million, or $0.08 per basic and diluted common share, for the year ended December 31, 2014.

Additionally, during the third quarter of 2014, we developed a plan to migrate customers from one of our networks to another over a one-year period beginning in the fourth quarter of 2014. As a result, we implemented changes in estimates that reduced the remaining economic lives of certain network assets. The increase in depreciation expense from the changes in estimates was more than fully offset by decreases in depreciation expense resulting from normal aging of our property, plant and equipment. These changes in the estimated remaining economic lives resulted in an increase in depreciation expense of approximately $48 million and $12 million for the years ended December 31, 2015 and 2014, respectively. This increase in depreciation expense, net of tax, reduced consolidated net income by approximately $32 million, or $0.06 per basic and diluted common share and $7 million, or $0.01 per basic and diluted common share, for the years ended December 31, 2015 and 2014, respectively.

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, investments, long-term contracts, customer retention patterns, allowance for doubtful accounts, depreciation, amortization, asset valuations, internal labor capitalization rates, recoverability of assets (including deferred tax assets), impairment assessments, pension, post-retirement and other post-employment benefits, taxes, certain liabilities and other provisions and contingencies, are reasonable, based on information available at the time they are made. These estimates, judgments and assumptions can materially affect the reported amounts of assets, liabilities and components of stockholders' 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 14—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 eighteen months to over ten 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.

We periodically transfer optical capacity assets on our network to other telecommunications service carriers. These transactions are structured as indefeasible rights of use, commonly referred to as IRUs, which are the exclusive right to use a specified amount of capacity or fiber for a specified term, typically 20 years. We account for the cash consideration received on transfers of optical capacity assets and on all of the other elements deliverable under an IRU, as revenue ratably over the term of the agreement. We have not recognized revenue on any contemporaneous exchanges of our optical capacity assets for other optical capacity assets.

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. Based on our agreements with DIRECTV and Verizon Wireless, we offer these services through sales agency relationships which are reported on a net basis.

We have service level commitments pursuant to contracts with certain of our customers. To the extent that such service levels are not achieved or are otherwise disputed due to performance or service issues or other service interruptions or conditions, we will estimate the amount of credits to be issued and record a reduction to revenues, with a corresponding increase in the credit reserve.

USF, 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 charges, 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 $210 million, $214 million and $210 million for the years ended December 31, 2015, 2014 and 2013, 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

We file a consolidated federal income tax return with our eligible subsidiaries. The provision for income taxes consists of an amount for taxes currently payable, an amount for tax consequences deferred to future periods, adjustments to our liabilities for uncertain tax positions and amortization of investment tax credits. We record deferred income tax assets and liabilities reflecting future tax consequences attributable to tax net operating losses ("NOLs"), tax credit carryforwards and 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. In evaluating investments for classification as cash equivalents, we require that individual securities have original maturities of ninety days or less and that individual investment funds have dollar-weighted average maturities of ninety days or less. To preserve capital and maintain liquidity, we invest with financial institutions we deem to be of sound financial condition and in high quality and relatively risk-free investment products. Our cash investment policy limits the concentration of investments with specific financial institutions or among certain products and includes criteria related to credit worthiness of any particular financial institution.

Book overdrafts occur when checks have been issued but have not been presented to our controlled disbursement bank accounts for payment. Disbursement bank accounts allow us to delay funding of issued checks until the checks are presented for payment. Until the issued checks are presented for payment, the book overdrafts are included in accounts payable on our consolidated balance sheet. This activity is included in the operating activities section in our consolidated statements of cash flows.

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 acquired in connection with our acquisitions was recorded based on its estimated fair value as of its acquisition date plus the estimated value of any associated legally or contractually required retirement obligations. Purchased and constructed property, plant and equipment is recorded at cost, plus the estimated value of any associated legally or contractually required retirement obligations. 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 abnormal or 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 have asset retirement obligations associated with the legally or contractually required removal of a limited group of property, plant and equipment assets from leased properties and the disposal of certain hazardous materials present in our owned properties. When an asset retirement obligation is identified, usually in association with the acquisition of the asset, we record the fair value of the obligation as a liability. The fair value of the obligation is also capitalized as property, plant and equipment and then amortized over the estimated remaining useful life of the associated asset. Where the removal obligation is not legally binding, the net cost to remove assets is expensed in the period in which the costs are actually incurred.

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, capitalized software, trademarks and trade names, are initially recorded at estimated fair value. We amortize customer relationships primarily over an estimated life of 10 to 15 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 7 years, except for approximately $237 million of our capitalized software costs, which represents costs to develop an integrated billing and customer care system which is amortized using the straight-line method over a 20 year period. We amortize our other intangible assets predominantly using the sum-of-the-years-digits method over an estimated life of 4 years. Other intangible assets not arising from business combinations are initially recorded at cost. Where there are no legal, regulatory, contractual or other factors that would reasonably limit the useful life of an intangible asset, we classify the intangible asset as indefinite-lived and such intangible assets are not amortized.

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.

Our long-lived intangible assets, other than goodwill, with indefinite lives are assessed for impairment annually, or, under certain circumstances, more frequently, such as when events or changes in circumstances indicate there may be an impairment. These assets are carried at the estimated fair value at the time of acquisition and assets not acquired in acquisitions are recorded at historical cost. However, if their estimated fair value is less than the carrying amount, other indefinite-lived intangible assets are reduced to their estimated fair value through an impairment charge to our consolidated statements of operations.

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. Our reporting units are not discrete legal entities with discrete financial statements. Therefore, the equity carrying value and future cash flows must be estimated each time a goodwill impairment assessment is performed on a reporting unit. As a result, our assets, liabilities and cash flows are assigned to reporting units using reasonable and consistent allocation methodologies. Certain estimates, judgments and assumptions are required to perform these assignments. We believe these estimates, judgments and assumptions to be reasonable, but changes in many of these can significantly affect each reporting unit's equity carrying value and future cash flows utilized for our goodwill impairment assessment.

We are required to reassign goodwill to reporting units each time we reorganize our internal reporting structure which causes a change in the composition of our reporting units. Goodwill is reassigned to the reporting units using a relative fair value approach. We utilize the earnings before interest, taxes, depreciation and amortization as our allocation methodology as it represents a reasonable proxy for the fair value of the operations being reorganized.

See Note 2—Goodwill, Customer Relationships and Other Intangible Assets for additional information.

Pension and Post-Retirement Benefits

We recognize the funded status of our defined benefit and post-retirement plans as an asset or a liability on our consolidated balance sheet. Each year's actuarial gains or losses are a component of our other comprehensive income (loss), which is then included in our accumulated other comprehensive loss. Pension and post-retirement benefit expenses are recognized over the period in which the employee renders service and becomes eligible to receive benefits. We make significant assumptions (including the discount rate, expected rate of return on plan assets, mortality and health care trend rates) in computing the pension and post-retirement benefits expense and obligations. See Note 7—Employee Benefits for additional information.

Foreign Currency

Our results of operations include foreign subsidiaries, which are translated from the applicable functional currency to the United States Dollar using the average exchange rates during the reporting period, while assets and liabilities are translated at the reporting date. We include gains or losses from foreign currency remeasurement in other income, net in our consolidated statements of operations. Certain non-U.S. subsidiaries designate the local currency as their functional currency, and we record the translation of their assets and liabilities into U.S. Dollars at the balance sheet date as translation adjustments and include them as a component of accumulated other comprehensive loss in our consolidated balance sheets.

Common Stock

At December 31, 2015, we had 4 million unissued shares of CenturyLink, Inc. common stock reserved for acquisitions. In addition, we had 25 million shares authorized for future issuance under our equity incentive plans.

Preferred stock

Holders of outstanding CenturyLink, Inc. preferred stock are entitled to receive cumulative dividends, receive preferential distributions equal to $25 per share plus unpaid dividends upon CenturyLink, Inc.'s liquidation and vote as a single class with the holders of common stock.

Dividends

We pay dividends out of retained earnings to the extent we have retained earnings on the date the dividend is declared. If the dividend is in excess of our retained earnings on the declaration date, then the excess is drawn from our additional paid-in capital.

Recently Adopted Accounting Pronouncements

In 2015, we adopted Accounting Standards Update (“ASU”) 2015-03 “Simplifying the Presentation of Debt Issuance Costs” (ASU 2015-03) and ASU 2015-17 “Balance Sheet Classification of Deferred Taxes” (ASU 2015-17). Both ASUs are intended to simplify the presentation of financial information. ASU 2015-03 requires that debt issuance costs be presented as a reduction in the associated debt rather than as an other asset, net. ASU 2015-17 requires that deferred taxes be presented on a net basis by jurisdiction as either a net noncurrent asset or liability. The ASUs affect neither the timing of expense recognition related to the debt issuance costs nor the timing of income and expense recognition related to deferred income taxes.

We adopted both ASU 2015-03 and 2015-17 by retrospectively applying the requirements of the ASUs to our previously issued consolidated financial statements. The retrospective application had no impact on our net income (loss) or earnings (loss) per share for the years ended December 31, 2014 and 2013, but resulted in the following changes in our previously reported consolidated balance sheet as of December 31, 2014:


•	A decrease of $880 million in Total current assets;


•	A decrease of $164 million in Other assets, net;


•	A decrease of $168 million in Long-term debt; and


•	A decrease of $876 million in Deferred income taxes, net.

The adoption of the ASUs had no impact on our net cash provided by operating activities, but did change the presentation of the adjustments to reconcile net income and changes in other noncurrent assets and liabilities, net for the years ended December 31, 2014 and 2013.

In 2015, we adopted Accounting Standards Update (“ASU”) 2015-07 (“ASU 2015-07”), which retrospectively changed the disclosure requirements for certain investments that are valued based upon net asset value (“NAV”) as a practical expedient. ASU 2015-07 was issued to eliminate diversity among entities on what level in the fair value hierarchy such investments were assigned. Under ASU 2015-07, investments valued using NAV as a practical expedient are no longer assigned to a level in the fair value hierarchy rather the value associated with the investments is disclosed in a reconciliation of the total investments measured at fair value.

For us, the change in disclosure requirements as a result of the adoption of ASU 2015-07, only affects the disclosure of the fair value of our pension and post-retirement plan assets included in footnote 7, “Employee Benefits”. ASU 2015-07 results in $5.749 billion and $264 million of pension plan and post-retirement plan assets, respectively as of December 31, 2014, not being assigned to a level in the fair value hierarchy but rather disclosed as a separate line added to the fair value hierarchy table to present total plan assets. There was no change in total pension or post-retirement plan assets as of December 31, 2014 due to the adoption of ASU 2015-07.

Recent Accounting Pronouncements

Revenue Recognition

On May 28, 2014, the FASB issued ASU 2014-09, “Revenue from Contracts with Customers” (“ASU 2014-09” or “new standard”). The new standard 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. We currently do not defer any contract acquisition costs and defer contract fulfillment costs only up to the extent of any revenue deferred.

On July 9, 2015, the FASB approved the deferral of the effective date of ASU 2014-09 by one year until January 1, 2018. Early adoption is permitted as of January 1, 2017. ASU 2014-09 may be adopted by applying the provisions of the new 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 2017, if adopting early, otherwise in the first quarter of 2018. We have not yet decided which implementation method we will adopt. We are studying the new standard and are in the early stages of assessing the impact the new standard will have on us and our consolidated financial statements. We cannot at this time, however, provide any estimate of the impact of adopting the new standard.

Goodwill, Customer Relationships and Other Intangible Assets

12 Months Ended

Dec. 31, 2015

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,
	2015		2014
	(Dollars in millions)
Goodwill	$	20,742	20,755
Customer relationships, less accumulated amortization of $5,648 and $4,682	3,928		4,893
Indefinite-life intangible assets	269		268
Other intangible assets subject to amortization
Capitalized software, less accumulated amortization of $1,778 and $1,533	1,248		1,338
Trade names and patents, less accumulated amortization of $20 and $196	38		41
Total other intangible assets, net	$	1,555	1,647

Total amortization expense for intangible assets for the years ended December 31, 2015, 2014 and 2013 was $1.353 billion, $1.470 billion and $1.589 billion, respectively. As of December 31, 2015, the gross carrying amount of goodwill, customer relationships, indefinite-life and other intangible assets was $33.671 billion.

We estimate that total amortization expense for intangible assets for the years ending December 31, 2016 through 2020 will be as follows:



	(Dollars in millions)
2016	$	1,161
2017	1,056
2018	944
2019	827
2020	726

Our goodwill was derived from numerous acquisitions where the purchase price exceeded the fair value of the net assets acquired.

We assess our goodwill and other indefinite-lived intangible assets 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 fair value. Our annual impairment assessment date for goodwill is October 31, at which date we assessed our reporting units, which are business (excluding wholesale), consumer and wholesale. Our annual impairment assessment date for indefinite-lived intangible assets other than goodwill is December 31.

Our reporting units are not discrete legal entities with discrete financial statements. Our assets and liabilities are employed in and relate to the operations of multiple reporting units. For each reporting unit, we compare its estimated fair value of equity to its carrying value of equity that we assign to the reporting unit. If the estimated fair value of the reporting unit is greater than the carrying value, we conclude that no impairment exists. If the estimated fair value of the reporting unit is less than the carrying value, a second calculation is required in which the implied fair value of goodwill is compared to the carrying value of goodwill that we assigned to the reporting unit. If the implied fair value of goodwill is less than its carrying value, goodwill must be written down to its implied fair value.

At October 31, 2015, we estimated the fair value of our business (excluding wholesale), consumer and wholesale reporting units by considering both a market approach and a discounted cash flow method, which resulted in a Level 3 fair value measurement. 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 units beyond the cash flows from the discrete projection period. We discounted the estimated cash flows for our consumer and wholesale reporting units using a rate that represents their estimated weighted average cost of capital, which we determined to be approximately 6.0% as of the assessment date (which was comprised of an after-tax cost of debt of 3.3% and a cost of equity of 7.6%). We discounted the estimated cash flows of our business (excluding wholesale) reporting unit using a rate that represents its estimated weighted average cost of capital, which we determined to be approximately 7.0% as of the assessment date (which was comprised of an after-tax cost of debt of 3.3% and a cost of equity of 8.6%). We also reconciled the estimated fair values of the reporting units to our market capitalization as of October 31, 2015 and concluded that the indicated implied control premium of approximately 24.6% was reasonable based on recent transactions in the market place. As of October 31, 2015, based on our assessment performed with respect to these reporting units as described above, we concluded that our goodwill for our three reporting units was not impaired as of that date.

The following table shows the rollforward of goodwill assigned to our reportable segments from December 31, 2013 through December 31, 2015.



	Business			Consumer		Wholesale		Hosting		Total
	(Dollars in millions)
As of December 31, 2013	$	6,363		10,348		3,274		689		20,674
Purchase accounting adjustments	—			—		—		(11	)	(11	)
November 1, 2014 reorganization	4,022			(70	)	(3,274	)	(678	)	—
Acquisitions	92			—		—		—		92
As of December 31, 2014	$	10,477		10,278		—		—		20,755
Purchase accounting and other adjustments	(13		)	—		—		—		(13	)
As of December 31, 2015	$	10,464		10,278		—		—		20,742

During the year ended December 31, 2014, we acquired all of the outstanding stock of two companies for total consideration of $95 million, net of $2 million acquired cash and including immaterial future cash payments of which $92 million was attributed to goodwill and the remainder to various assets and liabilities. During 2015, we finalized the valuations for these acquisitions resulting in a $14 million decrease in goodwill, a $13 million increase in other intangible assets and a $1 million decrease in deferred income taxes, net. The acquisitions were consummated to expand the product offerings of our business segment and therefore the goodwill has been assigned to that segment. The goodwill is attributed primarily to expected future increases in business segment revenue from the sale of new products. The goodwill is not deductible for tax purposes.

The acquisitions did not materially impact the consolidated results of operations from the dates of the acquisitions in 2014 and would not materially impact pro forma results of operations.

For additional information on our segments, see Note 12—Segment Information.

We completed our qualitative assessment of our indefinite-lived intangible assets other than goodwill as of December 31, 2015 and concluded it is more likely than not that our indefinite-lived intangible assets are not impaired; thus, no impairment charge was recorded in 2015.

As of October 31, 2014, based on our assessment performed, we concluded that our goodwill for our then four reporting units was not impaired as of that date. During 2013, one of our previous reporting units experienced slower than previously projected revenues and margin growth and greater than anticipated competitive pressures and as a result, we recorded a non-cash, non-tax-deductible goodwill impairment charge of $1.092 billion for goodwill assigned to one of our then four reporting units.

- 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 Credit Facilities

12 Months Ended

Dec. 31, 2015

Debt Disclosure [Abstract]

Long-Term Debt and Credit Facilities

Long-term debt, including unamortized discounts and premiums and unamortized debt issuance costs, consisted of borrowings by CenturyLink, Inc. and certain of its subsidiaries, including Qwest Corporation, Qwest Capital Funding, Inc. and Embarq Corporation and subsidiaries ("Embarq"), were as follows:



			As of December 31,
	Interest Rates	Maturities	2015			2014
			(Dollars in millions)
CenturyLink, Inc.
Senior notes	5.150% - 7.650%	2017 - 2042	$	7,975		7,825
Credit facility and revolving line of credit⁽¹⁾	2.010% - 4.250%	2019	410			725
Term loan	2.180%	2019	358			380
Subsidiaries
Qwest Corporation
Senior notes	6.125% - 8.375%	2016 - 2055	7,229			7,311
Term loan	2.180%	2025	100			—
Qwest Capital Funding, Inc.
Senior notes	6.500% - 7.750%	2018 - 2031	981			981
Embarq Corporation and subsidiaries
Senior notes	7.082% - 7.995%	2016 - 2036	2,669			2,669
First mortgage bonds	7.125% - 8.770%	2017 - 2025	232			232
Other	9.000%	2019	150			150
Capital lease and other obligations	Various	Various	425			509
Unamortized discounts, net			(125		)	(111	)
Unamortized debt issuance costs			(179		)	(168	)
Total long-term debt			20,225			20,503
Less current maturities			(1,503		)	(550	)
Long-term debt, excluding current maturities			$	18,722		19,953

_______________________________________________________________________________


⁽¹⁾	The aggregate amount outstanding on our Credit Facility and revolving line of credit borrowings at December 31, 2015 and 2014 was $410 million and $725 million, respectively, with weighted average interest rates of 2.756% and 2.270%, respectively. These amounts change on a regular basis.

New Issuances

2015

On September 21, 2015, Qwest Corporation issued $400 million aggregate principal amount of 6.625% Notes due 2055, in exchange for net proceeds, after deducting underwriting discounts and other expenses, of approximately $386 million. The underwriting agreement included an over-allotment option granting the underwriters for the offering an opportunity to purchase additional 6.625% Notes due 2055. On September 30, 2015, Qwest Corporation issued an additional $10 million aggregate principal amount of the 6.625% Notes under this over-allotment option. All of the 6.625% Notes are unsecured obligations and may be redeemed by Qwest Corporation, in whole or in part, on or after September 15, 2020, at a redemption price equal to 100% of the principal amount redeemed plus accrued and unpaid interest to the redemption date.

On March 19, 2015, CenturyLink, Inc. issued in a private offering $500 million aggregate principal amount of 5.625% Notes due 2025, in exchange for net proceeds, after deducting underwriting discounts and other expenses, of approximately $494 million. The Notes are senior unsecured obligations and may be redeemed, in whole or in part, at any time before January 1, 2025 at a redemption price equal to the greater of 100% of the principal amount of the Notes or the sum of the present value of the remaining scheduled payments of principal and interest on the Notes, discounted to the redemption date in the manner described in the Notes, plus accrued and unpaid interest to the redemption date. At any time on or after January 1, 2025, CenturyLink, Inc. may redeem the Notes at par plus accrued and unpaid interest to the redemption date. In addition, at any time on or prior to April 1, 2018, CenturyLink, Inc. may redeem up to 35% of the principal amount of the Notes at a redemption price equal to 105.625% of the principal amount thereof, plus accrued and unpaid interest to the redemption date, with net cash proceeds of certain equity offerings. Under certain circumstances, CenturyLink, Inc. will be required to make an offer to repurchase the Notes at a price of 101% of the aggregate principal amount plus accrued and unpaid interest to the repurchase date. In October 2015, CenturyLink, Inc. exchanged all of the unregistered Notes issued on March 19, 2015 for fully-registered Notes.

2014

On September 29, 2014, Qwest Corporation issued $500 million aggregate principal amount of 6.875% Notes due 2054, in exchange for net proceeds, after deducting underwriting discounts and other expenses, of $483 million. The Notes are senior unsecured obligations and may be redeemed, in whole or in part, on or after October 1, 2019, at a redemption price equal to 100% of the principal amount redeemed plus accrued and unpaid interest to the redemption date.

Repayments

2015

On October 13, 2015, Qwest Corporation redeemed all $250 million of its 7.2% Notes due 2026, which resulted in an immaterial gain, and redeemed $150 million of its 6.875% Notes due 2033, which resulted in an immaterial loss.

On June 15, 2015, Qwest Corporation paid at maturity the $92 million principal amount of its 7.625% Notes.

On February 17, 2015, CenturyLink, Inc. paid at maturity the $350 million principal and accrued and unpaid interest due under its Series M 5.00% Notes.

2014

On October 1, 2014, Qwest Corporation paid at maturity the $600 million principal amount of its 7.50% Notes.

On April 1, 2014, a subsidiary of Embarq paid at maturity the $30 million principal amount of its 7.46% first mortgage bonds.

Credit Facility

On December 3, 2014, we amended our existing $2 billion revolving credit facility to extend the maturity date to December 3, 2019. The amended Credit Facility (the "Credit Facility") has 16 lenders, each with commitments ranging from $3.5 million to $198.5 million. The Credit Facility allows us to obtain revolving loans and to issue up to $400 million of letters of credit, which upon issuance reduce the amount available for other extensions of credit. Interest is assessed on borrowings using either the LIBOR or the base rate (each as defined in the Credit Facility) plus an applicable margin between 1.00% and 2.25% per annum for LIBOR loans and 0.00% and 1.25% per annum for base rate loans depending on our then current senior unsecured long-term debt rating. Our obligations under the Credit Facility are guaranteed by nine of our subsidiaries.

Term Loans, Revolving Line of Credit and Revolving Letter of Credit

On March 13, 2015, CenturyLink, Inc. amended its term loan agreement to reduce the interest rate payable by it thereunder and to modify some covenants to provide additional flexibility.

On February 20, 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 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 December 31, 2015, the outstanding principal balance on this term loan was $100 million.

In January 2015, CenturyLink, Inc. entered into a $100 million uncommitted revolving line of credit with one of the lenders under the Credit Facility. The amount available under this uncommitted revolving line of credit is reduced by any amount outstanding under the Credit Facility with the same lender. Interest is paid monthly based upon the LIBOR plus an applicable margin between 1.00% and 2.25% per annum. At December 31, 2015, CenturyLink, Inc. had $80 million borrowings outstanding under this uncommitted revolving line of credit.

In April 2011, we entered into a $160 million uncommitted revolving letter of credit facility which enables us to provide letters of credit under terms that may be more favorable than those under the Credit Facility. At December 31, 2015 and 2014, our outstanding letters of credit totaled $109 million and $124 million, respectively, under this facility.

Aggregate Maturities of Long-Term Debt

Set forth below is the aggregate principal amount of our long-term debt (excluding unamortized discounts, net and unamortized debt issuance costs) maturing during the following years:



	(Dollars in millions)⁽¹⁾
2016	$	1,503
2017	1,501
2018	251
2019	1,160
2020	1,032
2021 and thereafter	15,082
Total long-term debt	$	20,529

_______________________________________________________________________________


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

Interest Expense

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



	Years Ended December 31,
	2015			2014		2013
	(Dollars in millions)
Interest expense:
Gross interest expense	$	1,364		1,358		1,339
Capitalized interest	(52		)	(47	)	(41	)
Total interest expense	$	1,312		1,311		1,298

Covenants

Certain of our loan agreements contain various restrictions, as described more fully below. Under current circumstances, we believe the covenants currently in effect place no significant restriction on the transfer of funds from our consolidated subsidiaries to CenturyLink.

The senior notes of CenturyLink, Inc. were issued under an indenture dated March 31, 1994. This indenture restricts our ability to (i) incur, issue or create liens upon our property and (ii) consolidate with or merge into, or transfer or lease all or substantially all of our assets to any other party. The indenture does not contain any provisions that are impacted by our credit ratings or that restrict the issuance of new securities in the event of a material adverse change to us. However, if the credit ratings relating to certain of our long-term debt securities issued under this indenture are downgraded in the manner specified thereunder in connection with a "change of control" of CenturyLink, Inc., then we will be required to offer to repurchase such debt securities.

The senior notes of Qwest Corporation were issued under indentures dated April 15, 1990 and October 15, 1999. These indentures contain restrictions on the incurrence of liens and the consummation of certain transactions substantially similar to the above-described covenants in CenturyLink, Inc.'s March 31, 1994 indenture. The senior notes of Qwest Capital Funding, Inc. were issued under an indenture dated June 29, 1998 containing terms substantially similar to those set forth in Qwest Corporation's indentures.

Embarq's senior notes were issued pursuant to an indenture dated as of May 17, 2006. While Embarq is generally prohibited from creating liens on its property unless its senior notes are secured equally and ratably, Embarq can create liens on its property without equally and ratably securing its senior notes so long as the sum of all indebtedness so secured does not exceed 15% of Embarq's consolidated net tangible assets. The indenture contains customary events of default, none of which are impacted by Embarq's credit rating.

None of the above-listed indentures of CenturyLink, Inc., Qwest Corporation, Qwest Capital Funding, Inc. and Embarq contain any financial covenants or restrictions on the ability to issue new securities in accordance with the terms of the indenture.

Several of our Embarq subsidiaries have outstanding first mortgage bonds. Each issue of these first mortgage bonds is secured by substantially all of the property, plant and equipment of the issuing subsidiary. Approximately 10% of our net property, plant and equipment is pledged to secure the long-term debt of subsidiaries.

Under the Credit Facility, we, and our indirect subsidiary, Qwest Corporation, must maintain a debt to EBITDA (earnings before interest, taxes, depreciation and amortization, as defined in our Credit Facility) ratio of not more than 4.0:1.0 and 2.85:1.0, respectively, as of the last day of each fiscal quarter for the four quarters then ended. The Credit Facility also contains a negative pledge covenant, which generally requires us to secure equally and ratably any advances under the Credit Facility if we pledge assets or permit liens on our property for the benefit of other debtholders. The Credit Facility also has a cross payment default provision, and the Credit Facility and certain of our debt securities also have 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 ratios could be adversely affected by a wide range of events, including unforeseen expenses or contingencies. 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.

CenturyLink, Inc. and Qwest Corporation are both indebted under term loans, each of which includes covenants substantially similar to those set forth in the Credit Facility.

At December 31, 2015, we believe we were in compliance with all of the provisions and covenants contained in our Credit Facility and other material debt agreements.

Guarantees

We do not guarantee the debt of any unaffiliated parties, but certain of our subsidiaries guarantee the outstanding senior notes issued by other subsidiaries. In addition, seven of our largest non-regulated subsidiaries guarantee the obligations of (i) CenturyLink, Inc. under the Credit Facility and its term loan and (ii) Qwest Corporation under its term loan.

Subsequent Event

In January 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 approximately $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.

Accounts Receivable

12 Months Ended

Dec. 31, 2015

Receivables [Abstract]

Accounts Receivable

The following table presents details of our accounts receivable balances:



	As of December 31,
	2015			2014
	(Dollars in millions)
Trade and purchased receivables	$	1,789		1,821
Earned and unbilled receivables	288			307
Other	18			22
Total accounts receivable	2,095			2,150
Less: allowance for doubtful accounts	(152		)	(162	)
Accounts receivable, less allowance	$	1,943		1,988

We are exposed to concentrations of credit risk from residential and business customers within our local service area, business customers outside of our local service area and from other telecommunications service providers. 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)
2015	$	162	177	(187	)	152
2014	$	155	159	(152	)	162
2013	$	158	152	(155	)	155

Property, Plant and Equipment

12 Months Ended

Dec. 31, 2015

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	2015			2014
		(Dollars in millions)
Land	n/a	$	571		575
Fiber, conduit and other outside plant ⁽¹⁾	15-45	16,166			15,151
Central office and other network electronics ⁽²⁾	3-10	14,144			13,248
Support assets ⁽³⁾	3-30	7,000			6,578
Construction in progress ⁽⁴⁾	n/a	904			1,166
Gross property, plant and equipment		38,785			36,718
Accumulated depreciation		(20,716		)	(18,285	)
Net property, plant and equipment		$	18,069		18,433

_______________________________________________________________________________


⁽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, data centers, 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 $2.836 billion, $2.958 billion and $2.952 billion for the years ended December 31, 2015, 2014 and 2013, respectively.

In 2014, we recorded an impairment charge of $17 million in connection with a sale-leaseback transaction involving an office building which closed in the fourth quarter of 2014. This impairment charge is included in selling, general and administrative expense in our consolidated statement of operations for the year ended December 31, 2014.

Additionally, in 2014 we sold an office building for $12 million.

Asset Retirement Obligations

At December 31, 2015, our asset retirement obligations balance was primarily related to estimated future costs of removing equipment from leased properties and estimated future costs of properly disposing of asbestos and other hazardous materials upon remodeling or demolishing buildings. Asset retirement obligations are included in other long-term liabilities on our consolidated balance sheets.

The following table provides asset retirement obligation activity:



	Years Ended December 31,
	2015			2014		2013
	(Dollars in millions)
Balance at beginning of year	$	107		106		106
Accretion expense	7			7		7
Liabilities incurred	—			6		—
Liabilities settled	(2		)	(2	)	(4	)
Change in estimate	(21		)	(10	)	(3	)
Balance at end of year	$	91		107		106

During 2015, 2014 and 2013, we revised our estimates for the cost of removal of network equipment, asbestos remediation, and other obligations by $21 million, $10 million and $3 million, respectively. These revisions resulted in a reduction of the asset retirement obligation and offsetting reduction to gross property, plant and equipment and revisions to assets specifically identified are recorded as a reduction to accretion expense.

Severance and Leased Real Estate

12 Months Ended

Dec. 31, 2015

Restructuring and Related Activities [Abstract]

Severance and Leased Real Estate

Periodically, we have reductions in our workforce and have accrued liabilities for the related severance costs. These workforce reductions resulted primarily from the progression or completion of our post-acquisition integration plans, increased competitive pressures, cost reduction initiatives and reduced workload demands due to the loss of customers purchasing certain legacy 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. As noted in Note 12—Segment Information, we do not allocate these severance expenses to our segments.

We have recognized liabilities to reflect our estimates of the fair values of the existing lease obligations for real estate for which we have ceased using, net of estimated sublease rentals. Our fair value estimates were determined using discounted cash flow methods. We recognize expense to reflect accretion of the discounted liabilities and periodically, we adjust the expense when our actual subleasing experience differs from our initial estimates. We report the current portion of liabilities for ceased-use real estate leases in accrued expenses and other liabilities-other and report the noncurrent portion in deferred credits and other liabilities in our consolidated balance sheets. We report the related expenses in selling, general and administrative expenses in our consolidated statements of operations. At December 31, 2015, the current and noncurrent portions of our leased real estate accrual were $9 million and $71 million, respectively. The remaining lease terms range from 0.3 years to 10 years, with a weighted average of 8 years.

Changes in our accrued liabilities for severance expenses and leased real estate were as follows:



	Severance			Real Estate
	(Dollars in millions)
Balance at December 31, 2013	$	17		113
Accrued to expense	87			1
Payments, net	(78		)	(16	)
Reversals and adjustments	—			(2	)
Balance at December 31, 2014	26			96
Accrued to expense	96			—
Payments, net	(108		)	(13	)
Reversals and adjustments	—			(3	)
Balance at December 31, 2015	$	14		80

Employee Benefits

12 Months Ended

Dec. 31, 2015

Compensation and Retirement Disclosure [Abstract]

Employee Benefits

Pension, Post-Retirement and Other Post-Employment Benefits

We sponsor various defined benefit pension plans (qualified and non-qualified), which in the aggregate cover a substantial portion of our employees including legacy CenturyLink, legacy Qwest Communications International, Inc. ("Qwest") and legacy Embarq employees. On December 31, 2014, we merged our existing qualified pension plans, which included merging the Qwest Pension Plan and Embarq Retirement Pension Plan into the CenturyLink Retirement Plan. The CenturyLink Retirement Plan was renamed the CenturyLink Combined Pension Plan ("Combined Plan"). Pension benefits for participants of the new Combined Plan who are represented by a collective bargaining agreement are based on negotiated schedules. All other participants' pension benefits are based on each individual participant's years of service and compensation. We also maintain non-qualified pension plans for certain current and former highly compensated employees. We maintain post-retirement benefit plans that provide health care and life insurance benefits for certain eligible retirees. We also provide other post-employment benefits for eligible former employees. We use a December 31 measurement date for all our plans.

Pension Benefits

Current funding laws require a company with a pension shortfall to fund the annual cost of benefits earned in addition to a seven-year amortization of the shortfall. Our funding policy for our Combined Plan is to make contributions with the objective of accumulating sufficient assets to pay all qualified pension benefits when due under the terms of the plan. The accounting unfunded status of our qualified pension plan was $2.215 billion and $2.403 billion as of December 31, 2015 and 2014, respectively.

In 2015, we made a voluntary cash contribution of $100 million to our qualified pension plan and paid approximately $6 million of benefits directly to participants of our non-qualified pension plans. Based on current laws and circumstances, we are not required to make any contributions to our qualified pension plan in 2016, but we estimate that we will pay approximately $5 million of benefits to participants of our non-qualified pension plans.

Our pension plans contain provisions that allow us, from time to time, to offer lump sum payment options to certain former employees in settlement of their future retirement benefits. We record these payments as a settlement only if, in the aggregate, they exceed the sum of the annual service and interest costs for the plan's net periodic pension benefit costs, which represents the settlement threshold. In September 2015, we offered to make cash settlement payments in December 2015 to a group of former employees provided they accepted the offer by the end of October 2015. During the fourth quarter of 2015, we made cash settlement payments for the lump sum offer of approximately $356 million. The total amount of the lump sum settlement payments for the year ended December 31, 2015, which included the lump sum offer and lump sum elections from employees who terminated employment during the year, was less than the settlement threshold, therefore settlement accounting was not triggered in 2015. On December 8, 2014, lump sum pension settlement payments to terminated, but not-yet-retired legacy Qwest participants was $460 million, which exceeded the settlement threshold of $418 million. As a result, we were required to recognize a settlement charge of $63 million in 2014 to accelerate the recognition of a portion of the previously unrecognized actuarial losses in the qualified pension plan, which has been allocated and reflected in cost of services and products (exclusive of depreciation and amortization) and selling, general and administrative in our consolidated statement of operations for the year ended December 31, 2014. This charge reduced our recorded net income and retained earnings, with an offset to accumulated other comprehensive loss in shareholders’ equity. The amount of any future non-cash settlement charges will depend on the level of lump sum benefit payments made in 2016 and beyond.

Post-Retirement Benefits

Our post-retirement benefit plans provide post-retirement benefits to qualified retirees and allow (i) eligible employees retiring before certain dates to receive benefits at no or reduced cost and (ii) eligible employees retiring after certain dates to receive benefits on a shared cost basis. The post-retirement benefits not paid by the trust are funded by us and we expect to continue funding these post-retirement obligations as benefits are paid. The accounting unfunded status of our qualified post-retirement benefit plan was $3.374 billion and $3.477 billion as of December 31, 2015 and 2014, respectively.

No contributions were made to the post-retirement trusts in 2015, and we do not expect to make a contribution in 2016. However, in 2015 we paid approximately $116 million of benefits (net of participant contributions and direct subsidies) that were not payable by the trusts. We estimate that in 2016, we will pay approximately $137 million of benefits (net of participant contributions and direct subsidies) that are not payable by the trusts.

We expect our health care cost trend rate to decrease between 0.05% to 0.10% per year from 5.00% in 2016 to an ultimate rate of 4.50% in 2025. Our post-retirement benefit expense, for certain eligible legacy Qwest retirees and certain eligible legacy CenturyLink retirees, is capped at a set dollar amount. Therefore, those health care benefit obligations are not subject to increasing health care trends after the effective date of the caps.

A change of 100 basis points in the assumed initial health care cost trend rate would have had the following effects in 2015:



	100 Basis Points Change
	Increase		(Decrease)
	(Dollars in millions)
Effect on the aggregate of the service and interest cost components of net periodic post-retirement benefit expense (consolidated statement of operations)	$	3	(3	)
Effect on benefit obligation (consolidated balance sheet)	73		(68	)

Expected Cash Flows

The qualified pension, non-qualified pension and post-retirement health care benefit payments and premiums and life insurance premium payments are paid by us or distributed from plan assets. The estimated benefit payments provided below are based on actuarial assumptions using the demographics of the employee and retiree populations and have been reduced by estimated participant contributions.



	Pension Plans		Post-Retirement Benefit Plans	Medicare Part D Subsidy Receipts
	(Dollars in millions)
Estimated future benefit payments:
2016	$	1,059	309	(7	)
2017	1,010		300	(7	)
2018	991		290	(7	)
2019	973		283	(7	)
2020	954		276	(7	)
2021 - 2025	4,433		1,256	(30	)

Net Periodic Benefit Expense

The actuarial assumptions used to compute the net periodic benefit expense for our qualified pension, non-qualified pension and post-retirement benefit plans are based upon information available as of the beginning of the year, as presented in the following table.



	Pension Plans						Post-Retirement Benefit Plans
	2015		2014		2013		2015		2014		2013
Actuarial assumptions at beginning of year:
Discount rate	3.50% - 4.10%		4.20% - 5.10%		3.50% - 4.20%		3.80	%	4.50	%	3.60	%
Rate of compensation increase	3.25	%	3.25	%	3.25	%	N/A		N/A		N/A
Expected long-term rate of return on plan assets	7.50	%	7.50	%	7.50	%	7.50	%	6.00% - 7.50%		6.00% - 7.30%
Initial health care cost trend rate	N/A		N/A		N/A		6.00% / 6.50%		6.00% / 6.50%		6.50% / 7.00%
Ultimate health care cost trend rate	N/A		N/A		N/A		4.50	%	4.50	%	4.50	%
Year ultimate trend rate is reached	N/A		N/A		N/A		2025		2024		2022

_______________________________________________________________________________

N/A-Not applicable

Net periodic (income) expense for our qualified and non-qualified pension plans includes the following components:



	Pension Plans Years Ended December 31,
	2015			2014		2013
	(Dollars in millions)
Service cost	$	83		77		91
Interest cost	568			602		544
Expected return on plan assets	(898		)	(891	)	(896	)
Settlements	—			63		—
Recognition of prior service cost	5			5		5
Recognition of actuarial loss	161			22		84
Net periodic pension benefit income	$	(81	)	(122	)	(172	)

Net periodic expense (income) for our post-retirement benefit plans includes the following components:



	Post-Retirement Plans Years Ended December 31,
	2015			2014		2013
	(Dollars in millions)
Service cost	$	24		22		24
Interest cost	140			159		140
Expected return on plan assets	(21		)	(33	)	(39	)
Recognition of prior service cost	19			20		—
Recognition of actuarial loss	—			—		4
Net periodic post-retirement benefit expense	$	162		168		129

We report net periodic benefit (income) expense for our qualified pension, non-qualified pension and post-retirement benefit plans in both cost of services and products and selling, general and administrative expenses on our consolidated statements of operations for the years ended December 31, 2015, 2014 and 2013.

Benefit Obligations

The actuarial assumptions used to compute the funded status for the plans are based upon information available as of December 31, 2015 and 2014 and are as follows:



	Pension Plans				Post-Retirement Benefit Plans
	December 31,				December 31,
	2015		2014		2015		2014
Actuarial assumptions at end of year:
Discount rate	3.50% - 4.50%		3.50% - 4.10%		4.15	%	3.80	%
Rate of compensation increase	3.25	%	3.25	%	N/A		N/A
Initial health care cost trend rate	N/A		N/A		5.00% / 5.25%		6.00% / 6.50%
Ultimate health care cost trend rate	N/A		N/A		4.50	%	4.50	%
Year ultimate trend rate is reached	N/A		N/A		2025		2024

_______________________________________________________________________________

N/A-Not applicable

In 2015, we adopted the revised mortality table and projection scale released by the Society of Actuaries ("SOA"), which decreased the projected benefit obligation of our benefit plans by $379 million. In 2014, to better reflect the expected lifetimes of our plan participants, we adopted a new mortality table for our defined benefit plan. The table used was based on SOA tables and increased the projected benefit obligation by approximately $1.3 billion. The 2014 increase in the projected obligation was recognized as part of the net actuarial loss and is included in the other comprehensive loss, a portion of which is subject to be amortized over the remaining estimated life of plan participants (approximately 8 years).

The following tables summarize the change in the benefit obligations for the pension and post-retirement benefit plans:



	Pension Plans Years Ended December 31,
	2015			2014		2013
	(Dollars in millions)
Change in benefit obligation
Benefit obligation at beginning of year	$	15,042		13,401		14,881
Service cost	83			77		91
Interest cost	568			602		544
Plan amendments	(100		)	4		—
Actuarial loss (gain)	(800		)	2,269		(1,179	)
Settlements	—			(460	)	—
Benefits paid by company	(6		)	(6	)	(5	)
Benefits paid from plan assets	(1,438		)	(845	)	(931	)
Benefit obligation at end of year	$	13,349		15,042		13,401



	Post-Retirement Benefit Plans Years Ended December 31,
	2015			2014		2013
	(Dollars in millions)
Change in benefit obligation
Benefit obligation at beginning of year	$	3,830		3,688		4,075
Service cost	24			22		24
Interest cost	140			159		140
Participant contributions	57			69		96
Plan amendments	—			23		141
Direct subsidy receipts	8			9		13
Actuarial loss (gain)	(148		)	245		(399	)
Benefits paid by company	(181		)	(166	)	(266	)
Benefits paid from plan assets	(163		)	(219	)	(136	)
Benefit obligation at end of year	$	3,567		3,830		3,688

Our aggregate benefit obligation as of December 31, 2015, 2014 and 2013 was $16.916 billion, $18.872 billion and $17.089 billion, respectively.

Plan Assets

We maintain plan assets for our qualified pension plan and certain post-retirement benefit plans. The qualified pension plan's assets are used for the payment of pension benefits and certain eligible plan expenses. The post-retirement benefit plan's assets are used to pay health care benefits and premiums on behalf of eligible retirees and to pay certain eligible plan expenses. The expected rate of return on plan assets is the long-term rate of return we expect to earn on the plans' assets, net of administrative expenses paid from plan assets. The rate of return is determined by the strategic allocation of plan assets and the long-term risk and return forecast for each asset class. The forecasts for each asset class are generated primarily from an analysis of the long-term expectations of various third party investment management organizations. The expected rate of return on plan assets is reviewed annually and revised, as necessary, to reflect changes in the financial markets and our investment strategy.

The following tables summarize the change in the fair value of plan assets for the pension and post-retirement benefit plans:



	Pension Plans Years Ended December 31,
	2015			2014		2013
	(Dollars in millions)
Change in plan assets
Fair value of plan assets at beginning of year	$	12,571		12,346		12,321
Return on plan assets	(161		)	1,373		810
Employer contributions	100			157		146
Settlements	—			(460	)	—
Benefits paid from plan assets	(1,438		)	(845	)	(931	)
Fair value of plan assets at end of year	$	11,072		12,571		12,346



	Post-Retirement Benefit Plans Years Ended December 31,
	2015			2014		2013
	(Dollars in millions)
Change in plan assets
Fair value of plan assets at beginning of year	$	353		535		626
Return on plan assets	3			37		45
Benefits paid from plan assets	(163		)	(219	)	(136	)
Fair value of plan assets at end of year	$	193		353		535

Pension Plans: Our investment objective for the qualified pension plan assets is to achieve an attractive risk-adjusted return over time that will provide for the payment of benefits and minimize the risk of large losses. Our pension plan investment strategy is designed to meet this objective by broadly diversifying plan assets across numerous strategies with differing expected returns, volatilities and correlations. The pension plan assets have target allocations of 45% to interest rate sensitive investments and 55% to investments designed to provide higher expected returns than the interest rate sensitive investments. Interest rate sensitive investments include 30% of plan assets targeted primarily to long-duration investment grade bonds, 10% targeted to high yield and emerging market bonds and 5% targeted to diversified strategies, which primarily have exposures to global bonds, as well as some exposures to global stocks and commodities. Assets expected to provide higher returns than the interest rate sensitive assets include broadly diversified equity investments with targets of approximately 15% to U.S. equity markets and 15% to non-U.S. developed and emerging markets. Approximately 7% is targeted to broadly diversified multi-asset class strategies that have the flexibility to adjust exposures to different asset classes. Approximately 10% is allocated to private markets investments including funds primarily invested in private equity, private debt and hedge funds. Real estate investments are targeted at 8% of plan assets. At the beginning of 2016, our expected annual long-term rate of return on pension assets before consideration of administrative expenses is assumed to be 7.5%. However, projected increases in PBGC (Pension Benefit Guaranty Corporation) premium rates have now become large enough to reduce the annual long-term expected return net of administrative expenses to 7.0%.

Our non-qualified pension plans are not funded. We pay benefits directly to the participants of these plans.

Post-Retirement Benefit Plans: Our investment objective for the post-retirement benefit plans' assets is to achieve an attractive risk-adjusted return and minimize the risk of large losses over the expected life of the assets. Investment risk is managed by broadly diversifying assets across numerous strategies with differing expected returns, volatilities and correlations. Our investment strategy is designed to be consistent with the investment objective, with particular focus on providing liquidity for the reimbursement of our union-represented employees' post-retirement health care costs. The liquid post-retirement benefit plan assets (excluding private market investments) have target allocations of 20% to equities and 80% to non-equity investments. Specific target allocations within these broad categories are allowed to vary to meet reimbursement requirements. Liquid equity investments are broadly diversified with exposure to publicly traded U.S., non-U.S. and emerging market stocks. The 80% non-equity allocation includes investment grade bonds, real estate, hedge funds and diversified strategies. While no new private market investments have been made in recent years, the percent allocation to existing private market investments is expected to increase as liquid, publicly traded stocks are drawn down for the reimbursement of health care costs. At the beginning of 2016, our expected annual long-term rate of return on post-retirement benefit plan assets is assumed to be 7.0%.

Permitted investments: Plan assets are managed consistent with the restrictions set forth by the Employee Retirement Income Security Act of 1974, as amended, which requires diversification of assets and also generally prohibits defined benefit and welfare plans from investing more than 10% of their assets in securities issued by the sponsor company. At December 31, 2015 and 2014, the pension and post-retirement benefit plans did not directly own any shares of our common stock or any of our debt.

Derivative instruments: Derivative instruments are used to reduce risk as well as provide return. The pension and post-retirement benefit plans use exchange traded futures and swaps to gain exposure to equity and interest rate markets consistent with target asset allocations and to reduce risk relative to measurement of the benefit obligation, which is sensitive to interest rate changes. Foreign exchange forward contracts are used to manage currency exposures. Credit default swaps are used to manage credit risk exposures in a cost effective and targeted manner relative to transacting with physical corporate fixed income securities. Options are currently used to manage interest rate exposure taking into account the implied volatility and current pricing of the specific underlying market instrument. Some derivative instruments subject the plans to counterparty risk. The external investment managers, along with Plan Management, monitor counterparty exposure and mitigate this risk by diversifying the exposure among multiple high credit quality counterparties, requiring collateral and limiting exposure by periodically settling contracts.

The gross notional exposure of the derivative instruments directly held by the plans is shown below. The notional amount of the derivatives corresponds to market exposure but does not represent an actual cash investment.



	Gross Notional Exposure
	Pension Plans			Post-Retirement Benefit Plans
	Years Ended December 31,
	2015		2014	2015	2014
	(Dollars in millions)
Derivative instruments:
Exchange-traded U.S. equity futures	$	79	134	—	7
Exchange-traded Treasury and other interest rate futures	1,767		2,451	—	—
Interest rate swaps	550		579	—	—
Credit default swaps	189		382	—	—
Foreign exchange forwards	992		1,195	—	13
Options	285		529	—	—

Fair Value Measurements: 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. For additional information on the fair value hierarchy, see Note 10—Fair Value Disclosure.

At December 31, 2015, we used the following valuation techniques to measure fair value for assets. There were no changes to these methodologies during 2015:


•	Level 1—Assets were valued using the closing price reported in the active market in which the individual security was traded.


•	Level 2—Assets were valued using quoted prices in markets that are not active, broker dealer quotations, net asset value of shares held by the plans and other methods by which all significant inputs were observable at the measurement date.


•	Level 3—Assets were valued using unobservable inputs in which little or no market data exists as reported by the respective institutions at the measurement date.

The tables below present the fair value of plan assets by category and the input levels used to determine those fair values at December 31, 2015. It is important to note that the asset allocations do not include market exposures that are gained with derivatives. Investments include dividend and interest receivables, pending trades and accrued expenses.



	Fair Value of Pension Plan Assets at December 31, 2015
	Level 1		Level 2		Level 3	Total
	(Dollars in millions)
Investment grade bonds (a)	$	841	1,045		—	$	1,886
High yield bonds (b)	—		544		13	557
Emerging market bonds (c)	208		232		1	441
Convertible bonds (d)	—		2		—	2
U.S. stocks (f)	1,201		—		—	1,201
Non-U.S. stocks (g)	1,127		1		—	1,128
Multi-asset strategies (m)	376		—		—	376
Derivatives (n)	2		(6	)	—	(4		)
Cash equivalents and short-term investments (o)	—		192		—	192
Total investments, excluding investments valued at NAV	$	3,755	2,010		14	5,779
Investments valued at NAV						5,293
Total pension plan assets						$	11,072



	Fair Value of Post-Retirement Plan Assets at December 31, 2015
	Level 1		Level 2	Level 3	Total
	(Dollars in millions)
Investment grade bonds (a)	$	2	1	—	$	3
High yield bonds (b)	—		1	—	1
U.S. stocks (f)	16		—	—	16
Non-U.S. stocks (g)	12		—	—	12
Emerging market stocks (h)	4		—	—	4
Cash equivalents and short-term investments (o)	—		4	—	4
Total investments, excluding investments valued at NAV	$	34	6	—	40
Investments valued at NAV					153
Total post-retirement plan assets					$	193

The tables below present the fair value of plan assets by category and the input levels used to determine those fair values at December 31, 2014. It is important to note that the asset allocations do not include market exposures that are gained with derivatives. Investments include dividend and interest receivable, pending trades and accrued expenses.



	Fair Value of Pension Plan Assets at December 31, 2014
	Level 1		Level 2	Level 3	Total
	(Dollars in millions)
Investment grade bonds (a)	$	1,068	1,278	—	$	2,346
High yield bonds (b)	—		647	7	654
Emerging market bonds (c)	208		407	—	615
Convertible bonds (d)	—		4	—	4
U.S. stocks (f)	1,389		1	—	1,390
Non-U.S. stocks (g)	1,169		1	—	1,170
Derivatives (n)	2		15	—	17
Cash equivalents and short-term investments (o)	—		626	—	626
Total investments, excluding investments valued at NAV	$	3,836	2,979	7	6,822
Investments valued at NAV					5,749
Total pension plan assets					$	12,571



	Fair Value of Post-Retirement Plan Assets at December 31, 2014
	Level 1		Level 2	Level 3	Total
	(Dollars in millions)
Investment grade bonds (a)	$	5	1	—	$	6
High yield bonds (b)	—		1	—	1
U.S. stocks (f)	35		—	—	35
Non-U.S. stocks (g)	33		—	—	33
Emerging market stocks (h)	6		—	—	6
Cash equivalents and short-term investments (o)	—		8	—	8
Total investments, excluding investments valued at NAV	$	79	10	—	89
Investments valued at NAV					264
Total post-retirement plan assets					$	353

The table below presents the fair value of plan assets valued at NAV by category for our pension and post-retirement plans at December 31, 2015 and 2014. See Note 1 - Basis of Presentation and Summary of Significant Accounting Policies for additional information regarding the 2015 adoption of ASU 2015-07.



	Fair Value of Plan Assets Valued at NAV
	Pension Plans at December 31,			Post-Retirement Benefit Plans at December 31,
	2015		2014	2015	2014
	(Dollars in millions)
Investment grade bonds (a)	$	115	148	35	71
High yield bonds (b)	512		860	1	14
Emerging market bonds (c)	9		27	—	—
Convertible bonds (d)	—		10	—	—
Diversified strategies (e)	516		718	54	89
U.S. stocks (f)	70		86	—	—
Non-U.S. stocks (g)	289		384	—	—
Emerging market stocks (h)	64		102	—	—
Private equity (i)	526		673	21	28
Private debt (j)	371		394	2	3
Market neutral hedge funds (k)	825		1,026	17	25
Directional hedge funds (k)	594		558	1	1
Real estate (l)	968		699	20	28
Multi-asset strategies (m)	386		—	—	—
Cash equivalents and short-term investments (o)	48		64	2	5
Total investments valued at NAV	$	5,293	5,749	153	264

The plans' assets are invested in various asset categories utilizing multiple strategies and investment managers. For several of the investments in the tables above and discussed below, the plans own units in commingled funds and limited partnerships that invest in various types of assets. Interests in commingled funds are valued using the net asset value ("NAV") per unit of each fund. The NAV reported by the fund manager is based on the market value of the underlying investments owned by each fund, minus its liabilities, divided by the number of shares outstanding. Commingled funds can be redeemed at NAV within a year of the financial statement date. Investments in limited partnerships represent long-term commitments with a fixed maturity date, typically ten years and are also valued at NAV. Valuation inputs for these limited partnership interests are generally based on assumptions and other information not observable in the market. The assumptions and valuation methodologies of the pricing vendors, account managers, fund managers and partnerships are monitored and evaluated for reasonableness. Below is an overview of the asset categories, the underlying strategies and valuation inputs used to value the assets in the preceding tables:

(a) Investment grade bonds represent investments in fixed income securities as well as commingled bond funds comprised of U.S. Treasury securities, agencies, corporate bonds, mortgage-backed securities, asset-backed securities and commercial mortgage-backed securities. Treasury securities are valued at the bid price reported in the active market in which the security is traded and are classified as Level 1. The valuation inputs of other investment grade bonds primarily utilize observable market information and are based on a spread to U.S. Treasury securities and consider yields available on comparable securities of issuers with similar credit ratings. The primary observable inputs include references to the new issue market for similar securities, the secondary trading markets and dealer quotes. Option adjusted spread models are utilized to evaluate securities such as asset backed securities that have early redemption features. These securities are classified as Level 2. The commingled funds are valued at NAV based on the market value of the underlying fixed income securities using the same valuation inputs described above.

(b) High yield bonds represent investments in below investment grade fixed income securities as well as commingled high yield bond funds. The valuation inputs for the securities primarily utilize observable market information and are based on a spread to U.S. Treasury securities and consider yields available on comparable securities of issuers with similar credit ratings. These securities are primarily classified as Level 2. The commingled funds are valued at NAV based on the market value of the underlying high yield instruments using the same valuation inputs described above.

(c) Emerging market bonds represent investments in securities issued by governments and other entities located in developing countries as well as registered mutual funds and commingled emerging market bond funds. The valuation inputs for the securities utilize observable market information and are primarily based on dealer quotes or a spread relative to the local government bonds. The registered mutual fund is classified as Level 1 while individual securities are classified as Level 2. The commingled funds are valued at NAV based on the market value of the underlying emerging market bonds using the same valuation inputs described above.

(d) Convertible bonds primarily represent investments in corporate debt securities that have features that allow the debt to be converted into equity securities under certain circumstances. The valuation inputs for the individual convertible bonds primarily utilize observable market information including a spread to U.S. Treasuries and the value and volatility of the underlying equity security. Convertible bonds are classified as Level 2.

(e) Diversified strategies represent an investment in a commingled fund that primarily has exposures to global government, corporate and inflation linked bonds, global stocks and commodities. The commingled fund is valued at NAV based on the market value of the underlying investments. The valuation inputs utilize observable market information including published prices for exchange traded securities, bid prices for government bonds, and spreads and yields available for comparable fixed income securities with similar credit ratings.

(f) U.S. stocks represent investments in stocks of U.S. based companies as well as commingled U.S. stock funds. The valuation inputs for U.S. stocks are based on the last published price reported on the major stock market on which the securities are traded and are classified as Level 1. The commingled funds are valued at NAV based on the market value of the underlying investments using the same valuation inputs described above.

(g) Non-U.S. stocks represent investments in stocks of companies based in developed countries outside the U.S. as well as commingled funds. The valuation inputs for non-U.S. stocks are based on the last published price reported on the major stock market on which the securities are traded and are primarily classified as Level 1. The commingled funds are valued at NAV based on the market value of the underlying investments using the same valuation inputs described above.

(h) Emerging market stocks represent investments in a registered mutual fund and commingled funds comprised of stocks of companies located in developing markets. Registered mutual funds trade at the daily NAV, as determined by the market value of the underlying investments, and are classified as Level 1. The commingled funds are valued at NAV based on the market value of the underlying investments using the same valuation inputs described previously for individual stocks.

(i) Private equity represents non-public investments in domestic and foreign buy out and venture capital funds. Private equity funds are structured as limited partnerships and are valued according to the valuation policy of each partnership, subject to prevailing accounting and other regulatory guidelines. The partnerships are valued at NAV using valuation methodologies that give consideration to a range of factors, including but not limited to the price at which investments were acquired, the nature of the investments, market conditions, trading values on comparable public securities, current and projected operating performance, and financing transactions subsequent to the acquisition of the investments. These valuation methodologies involve a significant degree of judgment.

(j) Private debt represents non-public investments in distressed or mezzanine debt funds. Mezzanine debt instruments are debt instruments that are subordinated to other debt issues and may include embedded equity instruments such as warrants. Private debt funds are structured as limited partnerships and are valued at NAV according to the valuation policy of each partnership, subject to prevailing accounting and other regulatory guidelines. The valuation of underlying fund investments are based on factors including the issuer's current and projected credit worthiness, the security's terms, reference to the securities of comparable companies, and other market factors. These valuation methodologies involve a significant degree of judgment.

(k) Market neutral hedge funds hold investments in a diversified mix of instruments that are intended in combination to exhibit low correlations to market fluctuations. These investments are typically combined with futures to achieve uncorrelated excess returns over various markets. Directional hedge funds—This asset category represents investments that may exhibit somewhat higher correlations to market fluctuations than the market neutral hedge funds. Investments in hedge funds include both direct investments and investments in diversified funds of funds. Hedge Funds are valued at NAV based on the market value of the underlying investments which include publicly traded equity and fixed income securities and privately negotiated debt securities. The hedge funds are valued by third party administrators using the same valuation inputs previously described.

(l) Real estate represents investments in commingled funds and limited partnerships that invest in a diversified portfolio of real estate properties. These investments are valued at NAV according to the valuation policy of each fund or partnership, subject to prevailing accounting and other regulatory guidelines. The valuation inputs of the underlying properties are generally based on third-party appraisals that use comparable sales or a projection of future cash flows to determine fair value.

(m) Multi-asset strategies is a new allocation in 2015 and represents broadly diversified strategies that have the flexibility to tactically adjust exposures to different asset classes through time. This asset category includes investments in a registered mutual fund which is classified as Level 1 and a commingled fund which is valued at NAV based on the market value of the underlying investments.

(n) Derivatives include exchange traded futures contracts which are classified as Level 1, as well as privately negotiated over-the-counter swaps and options that are valued based on the change in interest rates or a specific market index and are classified as Level 2. The market values represent gains or losses that occur due to fluctuations in interest rates, foreign currency exchange rates, security prices, or other factors.

(o) Cash equivalents and short-term investments represent investments that are used in conjunction with derivatives positions or are used to provide liquidity for the payment of benefits or other purposes. The valuation inputs of securities are based on a spread to U.S. Treasury Bills, the Federal Funds Rate, or London Interbank Offered Rate and consider yields available on comparable securities of issuers with similar credit ratings and are classified as Level 2. The commingled funds are valued at NAV based on the market value of the underlying investments using the same valuation inputs described above.

Concentrations of Risk: Investments, in general, are exposed to various risks, such as significant world events, interest rate, credit, foreign currency and overall market volatility risk. These risks are managed by broadly diversifying assets across numerous asset classes and strategies with differing expected returns, volatilities and correlations. Risk is also broadly diversified across numerous market sectors and individual companies. Financial instruments that potentially subject the plans to concentrations of counterparty risk consist principally of investment contracts with high quality financial institutions. These investment contracts are typically collateralized obligations and/or are actively managed, limiting the amount of counterparty exposure to any one financial institution. Although the investments are well diversified, the value of plan assets could change materially depending upon the overall market volatility, which could affect the funded status of the plans.

The table below presents a rollforward of the pension plan assets valued using Level 3 inputs:



	Pension Plan Assets Valued Using Level 3 Inputs
	High Yield Bonds			Emerging Market Bonds	Total
	(Dollars in millions)
Balance at December 31, 2013	$	—		—	—
Net transfers	6			—	6
Acquisitions	1			—	1
Dispositions	(3		)	—	(3	)
Actual return on plan assets:
Gains relating to assets sold during the year	4			—	4
(Losses) gains relating to assets still held at year-end	(1		)	—	(1	)
Balance at December 31, 2014	7			—	7
Net transfers	4			1	5
Acquisitions	4			—	4
Dispositions	(2		)	—	(2	)
Actual return on plan assets:
Gains relating to assets sold during the year	—			—	—
(Losses) gains relating to assets still held at year-end	—			—	—
Balance at December 31, 2015	$	13		1	14

Certain gains and losses are allocated between assets sold during the year and assets still held at year-end based on transactions and changes in valuations that occurred during the year. These allocations also impact our calculation of net acquisitions and dispositions.

For the year ended December 31, 2015, the investment program produced actual losses on qualified pension and post-retirement plan assets of $158 million as compared to expected returns of $919 million for a difference of $1.077 billion. For the year ended December 31, 2014, the investment program produced actual gains on pension and post-retirement plan assets of $1.410 billion as compared to the expected returns of $924 million for a difference of $486 million. The short-term annual returns on plan assets will almost always be different from the expected long-term returns and the plans could experience net gains or losses, due primarily to the volatility occurring in the financial markets during any given year.

Unfunded Status

The following table presents the unfunded status of the pensions and post-retirement benefit plans:



	Pension Plans					Post-Retirement Benefit Plans
	Years Ended December 31,					Years Ended December 31,
	2015			2014		2015		2014
	(Dollars in millions)
Benefit obligation	$	(13,349	)	(15,042	)	(3,567	)	(3,830	)
Fair value of plan assets	11,072			12,571		193		353
Unfunded status	(2,277		)	(2,471	)	(3,374	)	(3,477	)
Current portion of unfunded status	$	(5	)	(6	)	(135	)	(134	)
Non-current portion of unfunded status	$	(2,272	)	(2,465	)	(3,239	)	(3,343	)

The current portion of our post-retirement benefit obligations is recorded on our consolidated balance sheets in accrued expenses and other current liabilities-salaries and benefits.

Accumulated Other Comprehensive Loss-Recognition and Deferrals

The following tables present cumulative items not recognized as a component of net periodic benefits expense as of December 31, 2014, items recognized as a component of net periodic benefits expense in 2015, additional items deferred during 2015 and cumulative items not recognized as a component of net periodic benefits expense as of December 31, 2015. The items not recognized as a component of net periodic benefits expense have been recorded on our consolidated balance sheets in accumulated other comprehensive loss:



	As of and for the Years Ended December 31,
	2014			Recognition of Net Periodic Benefits Expense		Deferrals		Net Change in AOCL		2015
	(Dollars in millions)
Accumulated other comprehensive loss:
Pension plans:
Net actuarial (loss) gain	$	(2,760	)	161		(258	)	(97	)	(2,857	)
Prior service (cost) benefit	(32		)	5		99		104		72
Deferred income tax benefit (expense)	1,072			(63	)	61		(2	)	1,070
Total pension plans	(1,720		)	103		(98	)	5		(1,715	)
Post-retirement benefit plans:
Net actuarial (loss) gain	(277		)	—		130		130		(147	)
Prior service (cost) benefit	(166		)	19		—		19		(147	)
Deferred income tax benefit (expense)	171			(7	)	(50	)	(57	)	114
Total post-retirement benefit plans	(272		)	12		80		92		(180	)
Total accumulated other comprehensive loss	$	(1,992	)	115		(18	)	97		(1,895	)

The following table presents estimated items to be recognized in 2016 as a component of net periodic benefit expense of the pension, non-qualified pension and post-retirement benefit plans:



	Pension Plans			Post-Retirement Plans
	(Dollars in millions)
Estimated recognition of net periodic benefit (cost)/income in 2016:
Net actuarial loss	$	(168	)	—
Prior service (cost)/income	8			(20	)
Deferred income tax benefit	61			8
Estimated net periodic benefit expense to be recorded in 2016 as a component of other comprehensive income (loss)	$	(99	)	(12	)

Medicare Prescription Drug, Improvement and Modernization Act of 2003

We sponsor post-retirement health care plans with several benefit options that provide prescription drug benefits that we deem actuarially equivalent to or exceeding Medicare Part D. We recognize the impact of the federal subsidy received under the Medicare Prescription Drug, Improvement and Modernization Act of 2003 in the calculation of our 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 $381 million, $381 million and $362 million for the years ended December 31, 2015, 2014 and 2013, respectively. Union-represented employee benefits are based on negotiated collective bargaining agreements. Employees contributed $125 million, $136 million and $117 million for the years ended December 31, 2015, 2014 and 2013, respectively. Our group basic life insurance plans are fully insured and the premiums are paid by us.

401(k) Plans

We sponsor 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 employee contributions in cash. At both December 31, 2015 and 2014, the assets of the plans included approximately 8 million shares of our common stock as a result of the combination of previous employer match and participant directed contributions. We recognized expenses related to these plans of $83 million, $81 million and $89 million and for the years ended December 31, 2015, 2014 and 2013, respectively.

Deferred Compensation Plans

We sponsored non-qualified unfunded deferred compensation plans for various groups that included certain of our current and former highly compensated employees. The value of liabilities related to these plans was not significant.

Share-based Compensation

12 Months Ended

Dec. 31, 2015

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Share-based Compensation

We maintain equity programs that allow our Board of Directors (through its Compensation Committee or our Chief Executive Officer as its delegate) to grant incentives to certain employees and our outside directors in any one or a combination of several forms, including incentive and non-qualified stock options, stock appreciation rights, restricted stock awards, restricted stock units and market and performance shares. Stock options generally expire ten years from the date of grant. Until June 30, 2014, we offered an employee stock purchase plan, which allowed eligible employees to purchase our common stock at a 15% discount based on the lower of the beginning or ending stock price during recurring six month offering periods.

Stock Options

The following table summarizes activity involving stock option awards for the year ended December 31, 2015:



	Number of Options		Weighted- Average Exercise Price
	(in thousands)
Outstanding and Exercisable at December 31, 2014	4,106		$	37.99
Exercised	(335	)	26.00
Forfeited/Expired	(246	)	30.33
Outstanding and Exercisable at December 31, 2015	3,525		39.67

The aggregate intrinsic value of our options outstanding and exercisable at December 31, 2015 was $1 million. The weighted average remaining contractual term for such options was 1.9 years.

During 2015, we received net cash proceeds of $9 million in connection with our option exercises. The tax benefit realized from these exercises was $1 million. The total intrinsic value of options exercised for the years ended December 31, 2015, 2014 and 2013, was $4 million, $9 million and $11 million, respectively.

Restricted Stock Awards

For equity based awards that contain only service conditions for vesting, we calculate the award fair value based on the closing stock price on the accounting grant date. For equity based restricted stock awards that contain market conditions, the award fair value is calculated through Monte-Carlo simulations.

During the first quarter of 2015, we granted approximately 496 thousand shares of restricted stock to certain executive-level employees as part of our long-term incentive program, of which approximately 198 thousand contained only service conditions and will vest on a straight-line basis on February 23, 2016, 2017 and 2018. The remaining awards contain market and service conditions and are scheduled to vest on February 23, 2018. These shares, with market and service conditions, represent only the target for the award, as each recipient has the opportunity to ultimately receive a number of shares between 0% and 200% of the target restricted stock award depending on our total shareholder return versus that of selected peer companies for 2015, 2016 and 2017.

At the end of the first quarter of 2015, we granted approximately 1.2 million shares to certain key employees as part of our annual equity compensation program. These awards contained only service conditions and will vest on a straight-line basis on March 12, 2016, 2017 and 2018. During the third quarter of 2015 we granted shares to certain key employees as part of our long-term equity retention program. These awards will vest over a three to seven year period with approximately 193 thousand, 423 thousand and 230 thousand shares vesting on August 14, 2018, 2020 and 2022, respectively, and 55 thousand shares vesting equally on August 14, 2017, 2019, and 2021. The remaining awards granted throughout 2015 to certain other key employees and our outside directors were made as part of our equity compensation and retention programs. These awards require only service conditions for vesting and typically vest equally over a three year period.

During the first quarter of 2014, we granted approximately 440 thousand shares of restricted stock to certain executive-level employees as part of our long-term incentive program, of which approximately 250 thousand contained only service conditions and will vest on a straight-line basis on February 20, 2015, 2016 and 2017. The remaining awards contain market and service conditions and are scheduled to vest on February 20, 2017. These shares, with market and service conditions, represent only the target for the award, as each recipient has the opportunity to ultimately receive a number of shares between 0% and 200% of the target restricted stock award depending on our total shareholder return versus that of selected peer companies for 2014, 2015 and 2016.

During the second quarter of 2014, we granted approximately 1.5 million shares to certain key employees as part of our annual equity compensation program. These awards contained only service conditions and will vest on a straight-line basis on March 26, 2015, 2016 and 2017. During the third quarter of 2014 we granted shares to certain key employees as part of our long-term equity retention program. These awards will vest over a three to seven year period with approximately 105 thousand, 325 thousand and 220 thousand vesting on August 4, 2017, 2019 and 2021, respectively. The remaining awards granted throughout 2014 to certain other key employees and our outside directors were made as part of our equity compensation and retention programs. These awards require only service conditions for vesting and typically vest equally over a three year period.

During the second quarter of 2013, we granted approximately 335 thousand shares of restricted stock to certain executive-level employees as part of our long-term incentive program, of which approximately 223 thousand contained only service conditions and are scheduled to vest on a straight-line basis on May 23, 2014, 2015 and 2016. The remaining awards contain market and service conditions and will vest on May 23, 2016. These shares, with market and service conditions, represent only the target for the award as each recipient has the opportunity to ultimately receive a number of shares between 0% and 200% of the target restricted stock award depending on, our total shareholder return versus that of selected peer companies for 2013, 2014 and 2015.

In addition, during the first and second quarter of 2013, we granted approximately 1.2 million shares to certain key employees as part of our annual equity compensation program. These awards contained only service conditions. The remaining awards granted throughout 2013 to certain other key employees and our outside directors were made as part of our equity compensation and retention programs. These awards require only service conditions for vesting and typically vest equally over a three year period.

The following table summarizes activity involving restricted stock and restricted stock unit awards for the year ended December 31, 2015:



	Number of Shares		Weighted- Average Grant Date Fair Value
	(in thousands)
Non-vested at December 31, 2014	4,400		$	36.59
Granted	2,904		31.83
Vested	(1,724	)	35.71
Forfeited	(678	)	38.95
Non-vested at December 31, 2015	4,902		33.86

During 2014, we granted 2.9 million shares of restricted stock and restricted stock unit awards at a weighted-average price of $35.87. The total fair value of restricted stock that vested during 2015, 2014 and 2013, was $59 million, $53 million and $52 million, respectively.

Compensation Expense and Tax Benefit

We recognize compensation expense related to our market and performance share-based awards with graded vesting that only have a service condition on a straight-line basis over the requisite service period for the entire award. Total compensation expense for all share-based payment arrangements for the years ended December 31, 2015, 2014 and 2013, was $73 million, $75 million and $63 million, respectively. Our tax benefit recognized in the consolidated statements of operations for our share-based payment arrangements for the years ended December 31, 2015, 2014 and 2013, was $28 million, $29 million and $25 million, respectively. At December 31, 2015, there was $113 million of total unrecognized compensation expense related to our share-based payment arrangements, which we expect to recognize over a weighted-average period of 2.5 years.

Earnings (Loss) Per Common Share

12 Months Ended

Dec. 31, 2015

Earnings Per Share [Abstract]

Earnings (Loss) Per Common Share

Basic and diluted earnings (loss) per common share for the years ended December 31, 2015, 2014 and 2013 were calculated as follows:



	Years Ended December 31,
	2015			2014		2013
	(Dollars in millions, except per share amounts, shares in thousands)
Income (Loss) (Numerator):
Net income (loss)	$	878		772		(239	)
Earnings applicable to non-vested restricted stock	—			—		—
Net income (loss) applicable to common stock for computing basic earnings (loss) per common share	878			772		(239	)
Net income (loss) as adjusted for purposes of computing diluted earnings (loss) per common share	$	878		772		(239	)
Shares (Denominator):
Weighted average number of shares:
Outstanding during period	559,260			572,748		604,404
Non-vested restricted stock	(4,982		)	(4,313	)	(3,512	)
Weighted average shares outstanding for computing basic earnings (loss) per common share	554,278			568,435		600,892
Incremental common shares attributable to dilutive securities:
Shares issuable under convertible securities	10			10		—
Shares issuable under incentive compensation plans	805			1,294		—
Number of shares as adjusted for purposes of computing diluted earnings (loss) per common share	555,093			569,739		600,892
Basic earnings (loss) per common share	$	1.58		1.36		(0.40	)
Diluted earnings (loss) per common share	$	1.58		1.36		(0.40	)

Our calculation of diluted earnings (loss) per common share excludes shares of common stock that are issuable upon exercise of stock options when the exercise price is greater than the average market price of our common stock. We also exclude unvested restricted stock awards that are antidilutive as a result of unrecognized compensation cost. Such shares averaged 3.1 million, 2.5 million and 2.7 million for 2015, 2014 and 2013, respectively. For the year ended December 31, 2013, due to the net loss position, we excluded from the calculation of diluted loss per share 1.3 million shares which were potentially issuable under incentive compensation plans or convertible securities, as their effect, if included, would have been anti-dilutive.

Fair Value Disclosure

12 Months Ended

Dec. 31, 2015

Fair Value Disclosures [Abstract]

Fair Value Disclosure

Our financial instruments consist of cash and cash equivalents, accounts receivable, accounts payable and long-term debt, excluding capital lease obligations. Due to their short-term nature, the carrying amounts of our cash and cash equivalents, accounts receivable and accounts payable 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 indicated below:



		As of December 31, 2015			As of December 31, 2014
	Input Level	Carrying Amount		Fair Value	Carrying Amount	Fair Value
		(Dollars in millions)
Liabilities-Long-term debt excluding capital lease and other obligations	2	$	19,800	19,473	19,994	21,255

- 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

Income Taxes

12 Months Ended

Dec. 31, 2015

Income Tax Disclosure [Abstract]

Income Taxes



	Years Ended December 31,
	2015		2014		2013
	(Dollars in millions)
Income tax expense was as follows:
Federal
Current	$	28	18		1
Deferred	329		305		403
State
Current	40		26		62
Deferred	21		(14	)	(8	)
Foreign
Current	16		3		9
Deferred	4		—		(4	)
Total income tax expense	$	438	338		463



	Years Ended December 31,
	2015			2014		2013
	(Dollars in millions)
Income tax expense was allocated as follows:
Income tax expense in the consolidated statements of operations:
Attributable to income	$	438		338		463
Stockholders' equity:
Compensation expense for tax purposes in excess of amounts recognized for financial reporting purposes	(5		)	(5	)	(14	)
Tax effect of the change in accumulated other comprehensive loss	59			(744	)	554

The following is a reconciliation from the statutory federal income tax rate to our effective income tax rate:



	Years Ended December 31,
	2015		2014		2013
	(Percentage of pre-tax income)
Statutory federal income tax rate	35.0	%	35.0	%	35.0	%
State income taxes, net of federal income tax benefit	2.6	%	2.7	%	2.8	%
Impairment of goodwill	—	%	—	%	188.5	%
Change in liability for unrecognized tax position	0.4	%	0.4	%	(24.5	)%
Foreign income taxes	0.7	%	0.4	%	2.7	%
Nondeductible accounting adjustment for life insurance	—	%	—	%	3.1	%
Affiliate debt rationalization	(2.6	)%	—	%	—	%
Release state valuation allowance	—	%	—	%	(2.3	)%
Research and development credits	(2.1	)%	—	%	—	%
Loss on worthless investment in foreign subsidiary	—	%	(5.4	)%	—	%
Other, net	(0.7	)%	(2.6	)%	1.4	%
Effective income tax rate	33.3	%	30.5	%	206.7	%

The 2015 effective tax rate is 33.3% compared to 30.5% for 2014. The 2015 rate reflects a tax benefit of approximately $34 million related to affiliate debt rationalization, research and development tax credits of $28 million for 2011 through 2015 and a $16 million tax decrease due to changes in state taxes caused by apportionment changes, state tax rate changes and the changes in the expected utilization of net operating losses ("NOLs"). The 2014 rate reflects a $60 million tax benefit associated with a deduction for tax basis for worthless stock in a wholly-owned foreign subsidiary as a result of developments in bankruptcy proceedings involving its sole asset and a $13 million tax decrease due to changes in the state taxes caused by apportionment changes, state tax rate changes and the changes in the expected utilization of NOLs. The 2013 rate reflects the tax effect of a $1.092 billion non-deductible goodwill impairment charge, a favorable settlement with the Internal Revenue Service of $33 million, a $22 million reduction due to the reversal of an uncertain tax position and the tax effect of a $17 million unfavorable accounting adjustment for non-deductible life insurance costs. Also in 2013, the tax rate was decreased by a $5 million reduction to the valuation allowance due to the estimated ability to utilize more state NOLs than previously expected.

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,
	2015			2014
	(Dollars in millions)
Deferred tax assets
Post-retirement and pension benefit costs	$	2,154		2,276
Net operating loss carryforwards	487			1,091
Other employee benefits	182			214
Other	458			602
Gross deferred tax assets	3,281			4,183
Less valuation allowance	(380		)	(409	)
Net deferred tax assets	2,901			3,774
Deferred tax liabilities
Property, plant and equipment, primarily due to depreciation differences	(3,841		)	(3,869	)
Goodwill and other intangible assets	(2,588		)	(2,908	)
Other	(38		)	(147	)
Gross deferred tax liabilities	(6,467		)	(6,924	)
Net deferred tax liability	$	(3,566	)	(3,150	)

Of the $3.566 billion and $3.150 billion net deferred tax liability at December 31, 2015 and 2014, respectively, $3.569 billion and $3.154 billion is reflected as a long-term liability and $3 million and $4 million is reflected as a net noncurrent deferred tax asset at December 31, 2015 and 2014, respectively.

At December 31, 2015, we had federal NOLs of $72 million and state NOLs of $13 billion. If unused, the NOLs will expire between 2016 and 2032; however, no significant amounts expire until 2021. At December 31, 2015, we had federal tax credits of $28 million. Additionally, we had $36 million ($23 million net of federal income tax) of state investment tax credit carryforwards that will expire between 2016 and 2025 if not utilized. In addition, at December 31, 2015, we had $79 million of federal alternative minimum tax, or AMT, credits. Our acquisitions of Qwest and SAVVIS, Inc. ("Savvis") caused "ownership changes" within the meaning of Section 382 of the Internal Revenue Code ("Section 382"). As a result, our ability to use these NOLs and AMT credits are subject to annual limits imposed by Section 382. Despite this, we expect to use substantially all of these tax attributes to reduce our future federal tax liabilities, although the timing of that use will depend upon our future earnings and future tax circumstances.

We establish valuation allowances when necessary to reduce the deferred tax assets to amounts we expect to realize. As of December 31, 2015, a valuation allowance of $380 million was established as it is more likely than not that this amount of net operating loss and tax credit carryforwards will not be utilized prior to expiration. Our valuation allowance at December 31, 2015 and 2014 is primarily related to state NOL carryforwards. This valuation allowance decreased by $29 million during 2015.

A reconciliation of the change in our gross unrecognized tax benefits (excluding both interest and any related federal benefit) from January 1 to December 31 for 2015 and 2014 is as follows:



	2015			2014
	(Dollars in millions)
Unrecognized tax benefits at beginning of year	$	17		14
Increase in tax positions taken in the current year	1			—
Increase in tax positions taken in the prior year	7			9
Decrease due to the reversal of tax positions taken in a prior year	(9		)	(2	)
Decrease from the lapse of statute of limitations	(1		)	(1	)
Settlements	—			(3	)
Unrecognized tax benefits at end of year	$	15		17

The total amount of unrecognized tax benefits that, if recognized, would impact the effective income tax rate was $32 million at both December 31, 2015 and 2014.

Our policy is to reflect interest expense associated with unrecognized tax benefits in income tax expense. We had accrued interest (presented before related tax benefits) of approximately $33 million and $30 million at December 31, 2015 and 2014, respectively.

We file income tax returns, including returns for our subsidiaries, with federal, state and local jurisdictions. Our uncertain income tax positions are related to tax years that are currently under or remain subject to examination by the relevant taxing authorities.

In 2013, Qwest filed an amended 2009 federal income tax return primarily to report the carryforward impact of prior year settlements. The refund for the 2009 amended return filed in 2013 was received in 2014. In 2014, Qwest filed an amended federal income tax return for 2010. The refund claim filed for 2010 was accepted by the IRS, and the refund was received in 2015. The 2010 amended return released certain general business credits that were required to be carried back to 2009. As a result, a subsequent 2009 federal amended return was filed by Qwest in 2014 to reflect the carrybacks from 2010. The 2009 refund claim filed in 2014 was accepted by the IRS and the refund was received in 2015.

Beginning with the 2012 tax year, our federal consolidated returns are subject to annual examination by the IRS.

Our open income tax years by major jurisdiction are as follows at December 31, 2015:



Jurisdiction		Open Tax Years
Federal		2012—current
State
Arizona		2010—current
Florida		2010—current
Other states		2011—current

Since the period for assessing additional liability typically begins upon the filing of a return, it is possible that certain jurisdictions could assess tax for years prior to the open tax years disclosed above. Additionally, it is possible that certain jurisdictions in which we do not believe we have an income tax filing responsibility, and accordingly did not file a return, may attempt to assess a liability, or that other jurisdictions to which we pay taxes may attempt to assert that we owe additional taxes.

Based on our current assessment of various factors, including (i) the potential outcomes of these ongoing examinations, (ii) the expiration of statute of limitations for specific jurisdictions, (iii) the negotiated settlement of certain disputed issues, and (iv) the administrative practices of applicable taxing jurisdictions, it is reasonably possible that the related unrecognized tax benefits for uncertain tax positions previously taken may decrease by up to $11 million within the next 12 months. The actual amount of such decrease, if any, will depend on several future developments and events, many of which are outside our control.

Segment Information

12 Months Ended

Dec. 31, 2015

Segment Reporting [Abstract]

Segment Information

We are organized into operating segments based on customer type, business and consumer. These operating segments are our two reportable segments in our consolidated financial statements:

•

Business Segment. Consists generally of providing strategic, legacy and data integration products and services to small, medium and enterprise business, wholesale and governmental customers, including other communication providers. Our strategic products and services offered to these customers include our MPLS, private line (including special access), Ethernet, high-speed Internet, colocation, managed hosting, cloud hosting and other ancillary services. Our legacy services offered to these customers primarily include switched access and local and long-distance voice services, including the sale of unbundled network elements ("UNEs") which allow our wholesale customers to use all or part of our network to provide voice and data services to their customers. Our data integration offerings include the sale of telecommunications equipment located on customers' premises and related professional services. These services include network management, installation and maintenance of data equipment and the building of proprietary fiber-optic broadband networks; and


•	Consumer Segment. Consists generally of providing strategic and legacy products and services to residential customers. Our strategic products and services offered to these customers include our high-speed Internet, video (including our Prism TV services) and wireless services. Our legacy services offered to these customers include local and long-distance voice services.

The following table summarizes our segment results for 2015, 2014 and 2013 based on the segment categorization we were operating under at December 31, 2015.



	Years Ended December 31,
	2015			2014		2013
	(Dollars in millions)
Total segment revenues	$	16,668		17,028		17,095
Total segment expenses	8,459			8,509		8,167
Total segment income	$	8,209		8,519		8,928
Total margin percentage	49		%	50	%	52	%
Business segment:
Revenues	$	10,647		11,034		11,091
Expenses	6,034			6,089		5,808
Income	$	4,613		4,945		5,283
Margin percentage	43		%	45	%	48	%
Consumer segment:
Revenues	$	6,021		5,994		6,004
Expenses	2,425			2,420		2,359
Income	$	3,596		3,574		3,645
Margin percentage	60		%	60	%	61	%

Product and Service Categories

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

•

Strategic services, which include primarily high-speed Internet, MPLS (which is a data networking technology that can deliver the quality of service required to support real-time voice and video), private line (including special access), Ethernet, colocation, hosting (including cloud hosting and managed hosting), video (including our facilities-based video services, which we now offer in 16 markets), VoIP and Verizon Wireless and other ancillary services;


•	Legacy services, which include primarily local and long-distance voice services, including the sale of UNEs, switched access and Integrated Services Digital Network ("ISDN") services (which use regular telephone lines to support voice, video and data applications);


•	Data integration, which includes the sale of telecommunications equipment located on customers' premises and related professional services, such as network management, installation and maintenance of data equipment and building of proprietary fiber-optic broadband networks for our governmental and business customers; and

•

Other operating revenues, which consist primarily of CAF support payments, USF support payments and USF surcharges. We receive federal support payments from both CAF Phase 1 and CAF Phase 2 programs, 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 high-speed Internet infrastructure in high-cost rural areas where we are not able to recover our costs from our customers. USF surcharges are the amounts we collect based on specific items we list on our customers' invoices to fund the FCC's universal service programs. We also generate other operating revenues from leasing and subleasing of space in our office buildings, warehouses and other properties. Because we centrally manage the activities that generate these other operating revenues, these revenues are not included in our segment revenues.

Our operating revenues for our products and services consisted of the following categories for the years ended December 31, 2015, 2014 and 2013:



	Years Ended December 31,
	2015		2014	2013
	(Dollars in millions)
Strategic services
Business high-bandwidth data services (1)	$	2,816	2,579	2,230
Business low-bandwidth data services (2)	2,052		2,345	2,577
Business hosting services (3)	1,281		1,316	1,259
Other business strategic services (4)	162		76	60
Consumer high-speed Internet services (5)	2,611		2,469	2,358
Other consumer strategic services (6)	421		381	292
Total strategic services revenues	9,343		9,166	8,776

Legacy services
Business legacy voice services (7)	2,590		2,780	2,916
Other business legacy services (8)	1,175		1,252	1,398
Consumer legacy voice services (7)	2,676		2,864	3,101
Other consumer legacy services (9)	311		276	248
Total legacy services revenues	6,752		7,172	7,663

Data integration
Business data integration	571		686	651
Consumer data integration	2		4	5
Total data integration revenues	573		690	656

Other revenues
High-cost support revenue (10)	732		528	547
Other revenue (11)	500		475	453
Total other revenues	1,232		1,003	1,000

Total revenues	$	17,900	18,031	18,095

______________________________________________________________________



(1)	Includes MPLS and Ethernet revenue
(2)	Includes private line and high-speed Internet revenue
(3)	Includes colocation, hosting (including cloud hosting and managed hosting) and hosting area network revenue
(4)	Includes primarily VoIP, video and IT services revenue
(5)	Includes high-speed Internet and related services revenue
(6)	Includes video and Verizon wireless revenue
(7)	Includes local and long-distance voice revenue
(8)	Includes UNEs, public access and other ancillary revenue
(9)	Includes switched access and other ancillary revenue
(10)	Includes CAF Phase 1, CAF Phase 2 and federal and state USF support revenue
(11)	Includes USF surcharges

During the first quarter of 2015, we determined that certain products and services associated with our acquisition of Savvis are more closely aligned to legacy services than to strategic services. As a result, these operating revenues are now reflected as legacy services. The revision resulted in a reduction of revenue from strategic services of $34 million and $47 million and a corresponding increase in revenue from legacy services for the years ended December 31, 2014 and 2013, respectively.

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 related expense for the amounts we remit to the government agencies. The total amount of such surcharges that we included in revenues aggregated approximately $544 million, $526 million and $489 million for the years ended December 31, 2015, 2014 and 2013, respectively. Those USF surcharges, where we record revenue, are included in "other" operating revenues and transaction tax surcharges 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 include in our bills to customers, for which we do not record any revenue or expense because we only act as a pass-through agent.

Allocations of Revenues and Expenses

Our segment revenues include all revenues from our strategic, legacy and data integration operations as described in more detail above. Segment revenues are based upon each customer's classification to an individual segment. We report our segment revenues based upon all services provided to that segment's customers. Our segment expenses for our two segments include specific expenses incurred as a direct result of providing services and products to segment customers, along with selling, general and administrative expenses that are directly associated with specific segment customers or activities; and allocated expenses which include network expenses, facilities expenses and other expenses such as fleet and real estate expenses. We do not assign depreciation and amortization expense or impairments to our segments, as the related assets and capital expenditures are centrally managed and are not monitored by or reported to the chief operating decision maker ("CODM") by segment. Generally speaking, severance expenses, restructuring expenses and certain centrally managed administrative functions (such as finance, information technology, legal and human resources) are not assigned to our segments. Interest expense is also excluded from segment results because we manage our financing on a total company basis and have not allocated assets or debt to specific segments. Other income, net is not monitored as a part of our segment operations and is therefore excluded from our segment results.

The following table reconciles segment income to net income for the years ended December 31, 2015, 2014 and 2013:



	Years Ended December 31,
	2015			2014		2013
	(Dollars in millions)
Total segment income	$	8,209		8,519		8,928
Other operating revenues	1,232			1,003		1,000
Depreciation and amortization	(4,189		)	(4,428	)	(4,541	)
Impairment of goodwill	—			—		(1,092	)
Other unassigned operating expenses	(2,647		)	(2,684	)	(2,842	)
Other expenses, net	(1,289		)	(1,300	)	(1,229	)
Income tax expense	(438		)	(338	)	(463	)
Net income (loss)	$	878		772		(239	)

We do not have any single 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.

- Definition

The entire disclosure for reporting segments including data and tables. Reportable segments include those that meet any of the following quantitative thresholds a) it's reported revenue, including sales to external customers and intersegment sales or transfers is 10 percent or more of the combined revenue, internal and external, of all operating segments b) the absolute amount of its reported profit or loss is 10 percent or more of the greater, in absolute amount of 1) the combined reported profit of all operating segments that did not report a loss or 2) the combined reported loss of all operating segments that did report a loss c) its assets are 10 percent or more of the combined assets of all operating segments.

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+ Details

Quarterly Financial Data (Unaudited)

12 Months Ended

Dec. 31, 2015

Quarterly Financial Information Disclosure [Abstract]

Quarterly Financial Data (Unaudited)



	First Quarter		Second Quarter	Third Quarter	Fourth Quarter	Total
	(Dollars in millions, except per share amounts)
2015
Operating revenues	$	4,451	4,419	4,554	4,476	17,900
Operating income	649		549	656	751	2,605
Net income	192		143	205	338	878
Basic earnings per common share	0.34		0.26	0.37	0.62	1.58
Diluted earnings per common share	0.34		0.26	0.37	0.62	1.58
2014
Operating revenues	$	4,538	4,541	4,514	4,438	18,031
Operating income	653		655	619	483	2,410
Net income	203		193	188	188	772
Basic earnings per common share	0.35		0.34	0.33	0.33	1.36
Diluted earnings per common share	0.35		0.34	0.33	0.33	1.36

During the third quarter of 2015, we recognized an incremental $158 million of revenue associated with the FCC's CAF Phase 2 support program, and an additional incremental $57 million in the fourth quarter of 2015. During the fourth quarter of 2015, we also recognized a tax benefit of approximately $34 million related to affiliate debt rationalization, research and development tax credits of $28 million for 2011 through 2015, and a $16 million tax decrease due to changes in state taxes caused by apportionment changes, state tax rate changes and the changes in the expected utilization of net operating losses ("NOLs").

During the fourth quarter of 2014, we recognized a $60 million tax benefit associated with a deduction for the tax basis for worthless stock in a wholly-owned foreign subsidiary as a result of developments in bankruptcy proceedings involving its sole asset that occurred in the first quarter of 2014. During the fourth quarter of 2014, we also recognized a pension settlement charge of $63 million.

Commitments and Contingencies

12 Months Ended

Dec. 31, 2015

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

We are vigorously defending against all of the matters described below under the headings "Pending Matters" and "Other Proceedings and Disputes." As a matter of course, we are prepared both to 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.

Pending Matters

In William Douglas Fulghum, et al. v. Embarq Corporation, et al., filed on December 28, 2007 in the United States District Court for the District of Kansas, a group of retirees filed a class action lawsuit challenging the decision to make certain modifications in retiree benefits programs relating to life insurance, medical insurance and prescription drug benefits, generally effective January 1, 2006 and January 1, 2008 (which, at the time of the modifications, was expected to reduce estimated future expenses for the subject benefits by more than $300 million). Defendants include Embarq, certain of its benefit plans, its Employee Benefits Committee and the individual plan administrator of certain of its benefits plans. Additional defendants include Sprint Nextel and certain of its benefit plans. The Court certified a class on certain of plaintiffs' claims, but rejected class certification as to other claims. On October 14, 2011, the Fulghum lawyers filed a new, related lawsuit, Abbott et al. v. Sprint Nextel et al. In Abbott, approximately 1,500 plaintiffs allege breach of fiduciary duty in connection with the changes in retiree benefits that also are at issue in the Fulghum case. The Abbott plaintiffs are all members of the class that was certified in Fulghum on claims for allegedly vested benefits (Counts I and III), and the Abbott claims are similar to the Fulghum breach of fiduciary duty claim (Count II), on which the Fulghum court denied class certification. The Court has stayed proceedings in Abbott indefinitely, except for limited discovery and motion practice as to approximately 80 of the plaintiffs. On February 14, 2013, the Fulghum court dismissed the majority of the plaintiffs' claims in the case. On interlocutory appeal, the United States Court of Appeals for the Tenth Circuit ruled on February 24, 2015, that the plan documents reviewed do not support any claim for vested benefits, and affirmed the district court's dismissal of claims based on those documents. The Tenth Circuit decision allowed a subset of claims for vested benefits to return to the district court for further proceedings. The Tenth Circuit also affirmed the district court's dismissal of all age discrimination claims. The Tenth Circuit reversed the district court's determination that the statute of repose under the Employee Retirement Income Security Act of 1974, as amended ("ERISA"), is a time bar to the breach of fiduciary duty claims of fifteen named plaintiffs. On June 10, 2015, the district court in Fulghum granted summary judgment to defendants on an additional group of claims for vested benefits. On July 27, 2015, pursuant to the terms of a stipulation by the parties, the district court in Fulghum granted judgment in favor of defendants on all remaining and unadjudicated vested benefits claims. This judgment is without prejudice to any rights the parties may have to pursue any additional appellate relief. As to any further proceedings that may occur in the district court, defendants will continue to vigorously contest any remaining claims in Fulghum and Abbott. We have not accrued a liability for these matters because we believe it is premature (i) to determine whether an accrual is warranted and (ii) if so, to determine a reasonable estimate of probable liability.

On July 16, 2013, Comcast MO Group, Inc. ("Comcast") filed a lawsuit in Colorado state court against Qwest Communications International, Inc. ("Qwest"). Comcast alleges Qwest breached the parties' 1998 tax sharing agreement ("TSA") when it refused to partially indemnify Comcast for a tax liability settlement Comcast reached with the Commonwealth of Massachusetts in a dispute to which we were not a party. Comcast seeks approximately $80 million in damages, excluding interest. Qwest and Comcast are parties to the TSA in their capacities as successors to the TSA's original parties, U S WEST, Inc., a telecommunications company, and MediaOne Group, Inc., a cable television company, respectively. In October 2014, the state court granted summary judgment in Qwest's favor. In December 2015, the Colorado Court of Appeals affirmed the judgment. Comcast has filed a petition with the Colorado Supreme Court to review the Court of Appeals judgment. We have not accrued a liability for this matter because we do not believe that liability is probable.

The local exchange carrier subsidiaries of CenturyLink are among hundreds of defendants nationwide in dozens of lawsuits filed by Sprint Communications Company and affiliates of Verizon Communications Inc. The plaintiffs in these suits have challenged the right of local exchange carriers to bill interexchange carriers for switched access charges for certain calls between mobile and wireline devices that are routed through an interexchange carrier. In the lawsuits, the plaintiffs are seeking refunds of access charges previously paid and relief from future access charges. In addition, these and some other interexchange carriers have ceased paying switched access charges on these calls. These lawsuits involving our local exchange carriers and many other carriers have been consolidated for pretrial purposes in the United States District Court for the District of Northern Texas. In November 2015, the Court dismissed the plaintiffs' federal law claims and granted them leave to file state law claims, if any. Some of the defendants, including our affiliated carriers, have petitioned the Federal Communications Commission to address these issues on an industry-wide basis.

As both an interexchange carrier and a local exchange carrier, we both pay and assess significant amounts of the access charges in question. The outcome of these disputes and suits, 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.

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 whom 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 the matters to judgment, as well as to evaluate and consider all reasonable settlement opportunities.

We are subject to various foreign, 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.

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,
	2015		2014	2013
	(Dollars in millions)
Assets acquired through capital leases	$	17	37	12
Depreciation expense	96		126	136
Cash payments towards capital leases	89		118	119



	As of December 31,
	2015		2014
	(Dollars in millions)
Assets included in property, plant and equipment	$	722	850
Accumulated depreciation	352		393

The future annual minimum payments under capital lease arrangements as of December 31, 2015 were as follows:



	Future Minimum Payments
	(Dollars in millions)
Capital lease obligations:
2016	$	85
2017	78
2018	76
2019	62
2020	47
2021 and thereafter	223
Total minimum payments	571
Less: amount representing interest and executory costs	(153		)
Present value of minimum payments	418
Less: current portion	(56		)
Long-term portion	$	362

Operating Leases

CenturyLink leases 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, 2015, 2014 and 2013, our gross rental expense was $467 million, $446 million and $455 million, respectively. We also received sublease rental income for the years ended December 31, 2015, 2014 and 2013 of $12 million, $14 million and $16 million, respectively.

At December 31, 2015, our future rental commitments for operating leases were as follows:



	Future Minimum Payments
	(Dollars in millions)
2016	$	301
2017	289
2018	268
2019	235
2020	209
2021 and thereafter	1,075
Total future minimum payments ⁽¹⁾	$	2,377

_______________________________________________________________________________


⁽¹⁾	Minimum payments have not been reduced by minimum sublease rentals of $87 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 $625 million at December 31, 2015. Of this amount, we expect to purchase $364 million in 2016, $144 million in 2017 through 2018, $46 million in 2019 through 2020 and $71 million in 2021 and thereafter. 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, 2015.

Other Financial Information

12 Months Ended

Dec. 31, 2015

Additional Financial Information Disclosure [Abstract]

Other financial information

Other Financial Information

Other Current Assets

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



	As of December 31,
	2015		2014
	(Dollars in millions)
Prepaid expenses	$	238	260
Materials, supplies and inventory	144		132
Assets held for sale	8		14
Deferred activation and installation charges	105		103
Other	86		71
Total other current assets	$	581	580

Assets held for sale includes several assets that we expect to sell within the next twelve months. During 2014, we sold our remaining 700 MHz A-Block wireless spectrum licenses, which we purchased in 2008 but never placed into service. As a result of changes in market conditions and prevailing spectrum prices, we recorded an impairment charge of $14 million, which is included in other income, net in our consolidated statements of operations for the for the year ended December 31, 2014. The sale closed on November 3, 2014, and we received $39 million in cash in the aggregate.

In January 2013, we sold $43 million of our wireless spectrum assets held for sale. The sale resulted in a gain of $32 million, which is recorded as other income, net on our consolidated statements of operations.

Selected Current Liabilities

Current liabilities reflected in our consolidated balance sheets include accounts payable and other current liabilities as follows:



	As of December 31
	2015		2014
	(Dollars in millions)
Accounts payable	$	968	1,226
Other current liabilities:
Accrued rent	$	32	34
Legal reserves	20		27
Other	168		149
Total other current liabilities	$	220	210

Included in accounts payable at December 31, 2015 and 2014, were $68 million and $80 million, respectively, representing book overdrafts and $94 million and $185 million, respectively, associated with capital expenditures.

Labor Union Contracts	12 Months Ended
Labor Union Contracts	Dec. 31, 2015
Labor Union Contracts
Concentration Risk Disclosure	Labor Union Contracts Approximately 37% of our employees are members of various bargaining units represented by the Communications Workers of America ("CWA") or the International Brotherhood of Electrical Workers ("IBEW"). As of December 31, 2015, approximately three hundred, or 2%, of our employees are subject to collective bargaining agreements that expired in 2015. We believe that relations with our employees continue to be generally good. We are currently negotiating the terms of new agreements covering these employees. Approximately one thousand, or 6%, of our employees are subject to collective bargaining agreements that expire in 2016.

Repurchase of CenturyLink Common Stock	12 Months Ended
Repurchase of CenturyLink Common Stock	Dec. 31, 2015
Equity [Abstract]
Repurchase of Common Stock	Repurchase of CenturyLink, Inc. Common Stock In February 2014, our Board of Directors authorized a 24-month program to repurchase up to an aggregate of $1 billion of our outstanding common stock. This 2014 stock repurchase program took effect on May 29, 2014, immediately upon the completion of our predecessor 2013 stock repurchase program. On December 7, 2015, we completed the 2014 stock repurchase program, repurchasing over the course of the program a total of 32.3 million shares in the open market at an average purchase price of $30.99 per share. During the year ended December 31, 2015, we repurchased 27.1 million shares of our outstanding common stock in the open market. These shares were repurchased for an aggregate market price of $800 million, or an average purchase price of $29.56 per share. The repurchased common stock has been retired.

Accumulated Other Comprehensive Loss

12 Months Ended

Dec. 31, 2015

Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]

Other Comprehensive Earnings

Accumulated Other Comprehensive Loss

The table below summarizes changes in accumulated other comprehensive loss recorded on our consolidated balance sheet by component for the year ended December 31, 2015:



	Pension Plans			Post-Retirement Benefit Plans		Foreign Currency Translation Adjustment and Other		Total
	(Dollars in millions)
Balance at December 31, 2014	$	(1,720	)	(272	)	(25	)	(2,017	)
Other comprehensive income (loss) before reclassifications	(98		)	80		(14	)	(32	)
Amounts reclassified from accumulated other comprehensive income	103			12		—		115
Net current-period other comprehensive income (loss)	5			92		(14	)	83
Balance at December 31, 2015	$	(1,715	)	(180	)	(39	)	(1,934	)

The table below presents further information about our reclassifications out of accumulated other comprehensive loss by component for the year ended December 31, 2015:



Year Ended December 31, 2015	Decrease (Increase) in Net Income			Affected Line Item in Consolidated Statement of Operations or Footnote Where Additional Information is Presented If The Amount is not Recognized in Net Income in Total
	(Dollars in millions)
Amortization of pension & post-retirement plans
Net actuarial loss	$	161		See Note 7—Employee Benefits
Prior service cost	24			See Note 7—Employee Benefits
Total before tax	185
Income tax expense (benefit)	(70		)	Income tax expense
Net of tax	$	115

The table below summarizes changes in accumulated other comprehensive loss recorded on our consolidated balance sheet by component for the year ended December 31, 2014:



	Pension Plans			Post-Retirement Benefit Plans		Foreign Currency Translation Adjustment and Other		Total
	(Dollars in millions)
Balance at December 31, 2013	$	(669	)	(122	)	(11	)	(802	)
Other comprehensive income (loss) before reclassifications	(1,107		)	(162	)	(15	)	(1,284	)
Amounts reclassified from accumulated other comprehensive income	56			12		1		69
Net current-period other comprehensive income (loss)	(1,051		)	(150	)	(14	)	(1,215	)
Balance at December 31, 2014	$	(1,720	)	(272	)	(25	)	(2,017	)

The table below presents further information about our reclassifications out of accumulated other comprehensive loss by component for the year ended December 31, 2014:



Year Ended December 31, 2014	Decrease (Increase) in Net Loss			Affected Line Item in Consolidated Statement of Operations or Footnote Where Additional Information is Presented If The Amount is not Recognized in Net Income in Total
	(Dollars in millions)
Amortization of pension & post-retirement plans
Net actuarial loss	$	85		See Note 7—Employee Benefits
Prior service cost	25			See Note 7—Employee Benefits
Total before tax	110
Income tax expense (benefit)	(42		)	Income tax expense
Insignificant items	1
Net of tax	$	69

- Definition

The entire disclosure for comprehensive income, which includes, but is not limited to, 1) the amount of income tax expense or benefit allocated to each component of other comprehensive income, including reclassification adjustments, 2) the reclassification adjustments for each classification of other comprehensive income and 3) the ending accumulated balances for each component of comprehensive income.

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+ Details

Dividends

12 Months Ended

Dec. 31, 2015

Dividends, Common Stock [Abstract]

Dividends

Our Board of Directors declared the following dividends payable in 2015 and 2014:

Date Declared

Record Date

Dividend

Per Share

Total Amount

Payment Date

(in millions)

November 10, 2015

11/24/2015

$

0.540

$

293

12/8/2015

August 25, 2015

9/8/2015

0.540

300

9/22/2015

May 20, 2015

6/2/2015

0.540

303

6/16/2015

February 23, 2015

3/6/2015

0.540

303

3/20/2015

November 11, 2014

11/24/2014

0.540

307

12/5/2014

August 19, 2014

8/29/2014

0.540

308

9/12/2014

May 28, 2014

6/9/2014

0.540

307

6/20/2014

February 24, 2014

3/10/2014

0.540

309

3/21/2014

The declaration of dividends is solely at the discretion of our Board of Directors.

- Definition

The entire disclosure for shareholders' equity comprised of portions attributable to the parent entity and noncontrolling interest, including other comprehensive income. Includes, but is not limited to, balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings, accumulated balance for each classification of other comprehensive income and amount of comprehensive income.

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+ Details

Basis of Presentation and Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2015

Accounting Policies [Abstract]

Consolidation, Policy [Policy Text Block]

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.

To simplify the overall presentation of our consolidated financial statements, we report immaterial amounts attributable to noncontrolling interests in certain of our subsidiaries as follows: (i) income attributable to noncontrolling interests in other income, net, (ii) equity attributable to noncontrolling interests in additional paid-in capital and (iii) cash flows attributable to noncontrolling interests in other, net financing activities.

Reclassification, Policy [Policy Text Block]

We reclassified certain prior period amounts to conform to the current period presentation, including the categorization of our revenues and our segment reporting. See Note 12—Segment Information for additional information. These changes had no impact on total revenues, total operating expenses or net income (loss) for any period.

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, investments, long-term contracts, customer retention patterns, allowance for doubtful accounts, depreciation, amortization, asset valuations, internal labor capitalization rates, recoverability of assets (including deferred tax assets), impairment assessments, pension, post-retirement and other post-employment benefits, taxes, certain liabilities and other provisions and contingencies, are reasonable, based on information available at the time they are made. These estimates, judgments and assumptions can materially affect the reported amounts of assets, liabilities and components of stockholders' 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 14—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 eighteen months to over ten 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.

We periodically transfer optical capacity assets on our network to other telecommunications service carriers. These transactions are structured as indefeasible rights of use, commonly referred to as IRUs, which are the exclusive right to use a specified amount of capacity or fiber for a specified term, typically 20 years. We account for the cash consideration received on transfers of optical capacity assets and on all of the other elements deliverable under an IRU, as revenue ratably over the term of the agreement. We have not recognized revenue on any contemporaneous exchanges of our optical capacity assets for other optical capacity assets.

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. Based on our agreements with DIRECTV and Verizon Wireless, we offer these services through sales agency relationships which are reported on a net basis.

We have service level commitments pursuant to contracts with certain of our customers. To the extent that such service levels are not achieved or are otherwise disputed due to performance or service issues or other service interruptions or conditions, we will estimate the amount of credits to be issued and record a reduction to revenues, with a corresponding increase in the credit reserve.

USF, 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 charges, 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 $210 million, $214 million and $210 million for the years ended December 31, 2015, 2014 and 2013, 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

We file a consolidated federal income tax return with our eligible subsidiaries. The provision for income taxes consists of an amount for taxes currently payable, an amount for tax consequences deferred to future periods, adjustments to our liabilities for uncertain tax positions and amortization of investment tax credits. We record deferred income tax assets and liabilities reflecting future tax consequences attributable to tax net operating losses ("NOLs"), tax credit carryforwards and 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. In evaluating investments for classification as cash equivalents, we require that individual securities have original maturities of ninety days or less and that individual investment funds have dollar-weighted average maturities of ninety days or less. To preserve capital and maintain liquidity, we invest with financial institutions we deem to be of sound financial condition and in high quality and relatively risk-free investment products. Our cash investment policy limits the concentration of investments with specific financial institutions or among certain products and includes criteria related to credit worthiness of any particular financial institution.

Book overdrafts occur when checks have been issued but have not been presented to our controlled disbursement bank accounts for payment. Disbursement bank accounts allow us to delay funding of issued checks until the checks are presented for payment. Until the issued checks are presented for payment, the book overdrafts are included in accounts payable on our consolidated balance sheet. This activity is included in the operating activities section in our consolidated statements of cash flows.

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 acquired in connection with our acquisitions was recorded based on its estimated fair value as of its acquisition date plus the estimated value of any associated legally or contractually required retirement obligations. Purchased and constructed property, plant and equipment is recorded at cost, plus the estimated value of any associated legally or contractually required retirement obligations. 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 abnormal or 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 have asset retirement obligations associated with the legally or contractually required removal of a limited group of property, plant and equipment assets from leased properties and the disposal of certain hazardous materials present in our owned properties. When an asset retirement obligation is identified, usually in association with the acquisition of the asset, we record the fair value of the obligation as a liability. The fair value of the obligation is also capitalized as property, plant and equipment and then amortized over the estimated remaining useful life of the associated asset. Where the removal obligation is not legally binding, the net cost to remove assets is expensed in the period in which the costs are actually incurred.

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, capitalized software, trademarks and trade names, are initially recorded at estimated fair value. We amortize customer relationships primarily over an estimated life of 10 to 15 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 7 years, except for approximately $237 million of our capitalized software costs, which represents costs to develop an integrated billing and customer care system which is amortized using the straight-line method over a 20 year period. We amortize our other intangible assets predominantly using the sum-of-the-years-digits method over an estimated life of 4 years. Other intangible assets not arising from business combinations are initially recorded at cost. Where there are no legal, regulatory, contractual or other factors that would reasonably limit the useful life of an intangible asset, we classify the intangible asset as indefinite-lived and such intangible assets are not amortized.

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.

Our long-lived intangible assets, other than goodwill, with indefinite lives are assessed for impairment annually, or, under certain circumstances, more frequently, such as when events or changes in circumstances indicate there may be an impairment. These assets are carried at the estimated fair value at the time of acquisition and assets not acquired in acquisitions are recorded at historical cost. However, if their estimated fair value is less than the carrying amount, other indefinite-lived intangible assets are reduced to their estimated fair value through an impairment charge to our consolidated statements of operations.

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. Our reporting units are not discrete legal entities with discrete financial statements. Therefore, the equity carrying value and future cash flows must be estimated each time a goodwill impairment assessment is performed on a reporting unit. As a result, our assets, liabilities and cash flows are assigned to reporting units using reasonable and consistent allocation methodologies. Certain estimates, judgments and assumptions are required to perform these assignments. We believe these estimates, judgments and assumptions to be reasonable, but changes in many of these can significantly affect each reporting unit's equity carrying value and future cash flows utilized for our goodwill impairment assessment.

We are required to reassign goodwill to reporting units each time we reorganize our internal reporting structure which causes a change in the composition of our reporting units. Goodwill is reassigned to the reporting units using a relative fair value approach. We utilize the earnings before interest, taxes, depreciation and amortization as our allocation methodology as it represents a reasonable proxy for the fair value of the operations being reorganized.

See Note 2—Goodwill, Customer Relationships and Other Intangible Assets for additional information.

Pension and Post-Retirement Benefits

We recognize the funded status of our defined benefit and post-retirement plans as an asset or a liability on our consolidated balance sheet. Each year's actuarial gains or losses are a component of our other comprehensive income (loss), which is then included in our accumulated other comprehensive loss. Pension and post-retirement benefit expenses are recognized over the period in which the employee renders service and becomes eligible to receive benefits. We make significant assumptions (including the discount rate, expected rate of return on plan assets, mortality and health care trend rates) in computing the pension and post-retirement benefits expense and obligations. See Note 7—Employee Benefits for additional information.

Foreign Currency

Our results of operations include foreign subsidiaries, which are translated from the applicable functional currency to the United States Dollar using the average exchange rates during the reporting period, while assets and liabilities are translated at the reporting date. We include gains or losses from foreign currency remeasurement in other income, net in our consolidated statements of operations. Certain non-U.S. subsidiaries designate the local currency as their functional currency, and we record the translation of their assets and liabilities into U.S. Dollars at the balance sheet date as translation adjustments and include them as a component of accumulated other comprehensive loss in our consolidated balance sheets.

Common Stock and Preferred Stock

Common Stock

At December 31, 2015, we had 4 million unissued shares of CenturyLink, Inc. common stock reserved for acquisitions. In addition, we had 25 million shares authorized for future issuance under our equity incentive plans.

Preferred stock

Holders of outstanding CenturyLink, Inc. preferred stock are entitled to receive cumulative dividends, receive preferential distributions equal to $25 per share plus unpaid dividends upon CenturyLink, Inc.'s liquidation and vote as a single class with the holders of common stock.

Dividends

We pay dividends out of retained earnings to the extent we have retained earnings on the date the dividend is declared. If the dividend is in excess of our retained earnings on the declaration date, then the excess is drawn from our additional paid-in capital.

New Accounting Pronouncements, Policy [Policy Text Block]

Recently Adopted Accounting Pronouncements

In 2015, we adopted Accounting Standards Update (“ASU”) 2015-03 “Simplifying the Presentation of Debt Issuance Costs” (ASU 2015-03) and ASU 2015-17 “Balance Sheet Classification of Deferred Taxes” (ASU 2015-17). Both ASUs are intended to simplify the presentation of financial information. ASU 2015-03 requires that debt issuance costs be presented as a reduction in the associated debt rather than as an other asset, net. ASU 2015-17 requires that deferred taxes be presented on a net basis by jurisdiction as either a net noncurrent asset or liability. The ASUs affect neither the timing of expense recognition related to the debt issuance costs nor the timing of income and expense recognition related to deferred income taxes.

We adopted both ASU 2015-03 and 2015-17 by retrospectively applying the requirements of the ASUs to our previously issued consolidated financial statements. The retrospective application had no impact on our net income (loss) or earnings (loss) per share for the years ended December 31, 2014 and 2013, but resulted in the following changes in our previously reported consolidated balance sheet as of December 31, 2014:


•	A decrease of $880 million in Total current assets;


•	A decrease of $164 million in Other assets, net;


•	A decrease of $168 million in Long-term debt; and


•	A decrease of $876 million in Deferred income taxes, net.

The adoption of the ASUs had no impact on our net cash provided by operating activities, but did change the presentation of the adjustments to reconcile net income and changes in other noncurrent assets and liabilities, net for the years ended December 31, 2014 and 2013.

In 2015, we adopted Accounting Standards Update (“ASU”) 2015-07 (“ASU 2015-07”), which retrospectively changed the disclosure requirements for certain investments that are valued based upon net asset value (“NAV”) as a practical expedient. ASU 2015-07 was issued to eliminate diversity among entities on what level in the fair value hierarchy such investments were assigned. Under ASU 2015-07, investments valued using NAV as a practical expedient are no longer assigned to a level in the fair value hierarchy rather the value associated with the investments is disclosed in a reconciliation of the total investments measured at fair value.

For us, the change in disclosure requirements as a result of the adoption of ASU 2015-07, only affects the disclosure of the fair value of our pension and post-retirement plan assets included in footnote 7, “Employee Benefits”. ASU 2015-07 results in $5.749 billion and $264 million of pension plan and post-retirement plan assets, respectively as of December 31, 2014, not being assigned to a level in the fair value hierarchy but rather disclosed as a separate line added to the fair value hierarchy table to present total plan assets. There was no change in total pension or post-retirement plan assets as of December 31, 2014 due to the adoption of ASU 2015-07.

Recent Accounting Pronouncements

Revenue Recognition

On May 28, 2014, the FASB issued ASU 2014-09, “Revenue from Contracts with Customers” (“ASU 2014-09” or “new standard”). The new standard 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. We currently do not defer any contract acquisition costs and defer contract fulfillment costs only up to the extent of any revenue deferred.

On July 9, 2015, the FASB approved the deferral of the effective date of ASU 2014-09 by one year until January 1, 2018. Early adoption is permitted as of January 1, 2017. ASU 2014-09 may be adopted by applying the provisions of the new 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 2017, if adopting early, otherwise in the first quarter of 2018. We have not yet decided which implementation method we will adopt. We are studying the new standard and are in the early stages of assessing the impact the new standard will have on us and our consolidated financial statements. We cannot at this time, however, provide any estimate of the impact of adopting the new standard.

Goodwill, Customer Relationships and Other Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2015

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of goodwill and other intangible assets

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



	As of December 31,
	2015		2014
	(Dollars in millions)
Goodwill	$	20,742	20,755
Customer relationships, less accumulated amortization of $5,648 and $4,682	3,928		4,893
Indefinite-life intangible assets	269		268
Other intangible assets subject to amortization
Capitalized software, less accumulated amortization of $1,778 and $1,533	1,248		1,338
Trade names and patents, less accumulated amortization of $20 and $196	38		41
Total other intangible assets, net	$	1,555	1,647

Schedule of estimated amortization expense for intangible assets

We estimate that total amortization expense for intangible assets for the years ending December 31, 2016 through 2020 will be as follows:



	(Dollars in millions)
2016	$	1,161
2017	1,056
2018	944
2019	827
2020	726

Schedule of goodwill attributable to segments

The following table shows the rollforward of goodwill assigned to our reportable segments from December 31, 2013 through December 31, 2015.



	Business			Consumer		Wholesale		Hosting		Total
	(Dollars in millions)
As of December 31, 2013	$	6,363		10,348		3,274		689		20,674
Purchase accounting adjustments	—			—		—		(11	)	(11	)
November 1, 2014 reorganization	4,022			(70	)	(3,274	)	(678	)	—
Acquisitions	92			—		—		—		92
As of December 31, 2014	$	10,477		10,278		—		—		20,755
Purchase accounting and other adjustments	(13		)	—		—		—		(13	)
As of December 31, 2015	$	10,464		10,278		—		—		20,742

Long-Term Debt and Credit Facilities (Tables)

12 Months Ended

Dec. 31, 2015

Debt Disclosure [Abstract]

Schedule of long-term debt including unamortized discounts and premiums

Long-term debt, including unamortized discounts and premiums and unamortized debt issuance costs, consisted of borrowings by CenturyLink, Inc. and certain of its subsidiaries, including Qwest Corporation, Qwest Capital Funding, Inc. and Embarq Corporation and subsidiaries ("Embarq"), were as follows:



			As of December 31,
	Interest Rates	Maturities	2015			2014
			(Dollars in millions)
CenturyLink, Inc.
Senior notes	5.150% - 7.650%	2017 - 2042	$	7,975		7,825
Credit facility and revolving line of credit⁽¹⁾	2.010% - 4.250%	2019	410			725
Term loan	2.180%	2019	358			380
Subsidiaries
Qwest Corporation
Senior notes	6.125% - 8.375%	2016 - 2055	7,229			7,311
Term loan	2.180%	2025	100			—
Qwest Capital Funding, Inc.
Senior notes	6.500% - 7.750%	2018 - 2031	981			981
Embarq Corporation and subsidiaries
Senior notes	7.082% - 7.995%	2016 - 2036	2,669			2,669
First mortgage bonds	7.125% - 8.770%	2017 - 2025	232			232
Other	9.000%	2019	150			150
Capital lease and other obligations	Various	Various	425			509
Unamortized discounts, net			(125		)	(111	)
Unamortized debt issuance costs			(179		)	(168	)
Total long-term debt			20,225			20,503
Less current maturities			(1,503		)	(550	)
Long-term debt, excluding current maturities			$	18,722		19,953

_______________________________________________________________________________


⁽¹⁾	The aggregate amount outstanding on our Credit Facility and revolving line of credit borrowings at December 31, 2015 and 2014 was $410 million and $725 million, respectively, with weighted average interest rates of 2.756% and 2.270%, respectively. These amounts change on a regular basis.

Schedule of maturities of long-term debt

Set forth below is the aggregate principal amount of our long-term debt (excluding unamortized discounts, net and unamortized debt issuance costs) maturing during the following years:



	(Dollars in millions)⁽¹⁾
2016	$	1,503
2017	1,501
2018	251
2019	1,160
2020	1,032
2021 and thereafter	15,082
Total long-term debt	$	20,529

_______________________________________________________________________________


⁽¹⁾	Actual principal paid in all years 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

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



	Years Ended December 31,
	2015			2014		2013
	(Dollars in millions)
Interest expense:
Gross interest expense	$	1,364		1,358		1,339
Capitalized interest	(52		)	(47	)	(41	)
Total interest expense	$	1,312		1,311		1,298

- 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=6928386&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=6479336&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=34725769&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=6928386&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=6928386&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=6451184&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=6451184&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=6928386&loc=d3e21521-112644

+ Details

Accounts Receivable (Tables)

12 Months Ended

Dec. 31, 2015

Receivables [Abstract]

Schedule of components of accounts receivable

The following table presents details of our accounts receivable balances:



	As of December 31,
	2015			2014
	(Dollars in millions)
Trade and purchased receivables	$	1,789		1,821
Earned and unbilled receivables	288			307
Other	18			22
Total accounts receivable	2,095			2,150
Less: allowance for doubtful accounts	(152		)	(162	)
Accounts receivable, less allowance	$	1,943		1,988

Schedule of details of allowance for doubtful accounts

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



	Beginning Balance		Additions	Deductions		Ending Balance
	(Dollars in millions)
2015	$	162	177	(187	)	152
2014	$	155	159	(152	)	162
2013	$	158	152	(155	)	155

Property, Plant and Equipment (Tables)

12 Months Ended

Dec. 31, 2015

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	2015			2014
		(Dollars in millions)
Land	n/a	$	571		575
Fiber, conduit and other outside plant ⁽¹⁾	15-45	16,166			15,151
Central office and other network electronics ⁽²⁾	3-10	14,144			13,248
Support assets ⁽³⁾	3-30	7,000			6,578
Construction in progress ⁽⁴⁾	n/a	904			1,166
Gross property, plant and equipment		38,785			36,718
Accumulated depreciation		(20,716		)	(18,285	)
Net property, plant and equipment		$	18,069		18,433

_______________________________________________________________________________


⁽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, data centers, 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.

Schedule of changes to asset retirement obligations

The following table provides asset retirement obligation activity:



	Years Ended December 31,
	2015			2014		2013
	(Dollars in millions)
Balance at beginning of year	$	107		106		106
Accretion expense	7			7		7
Liabilities incurred	—			6		—
Liabilities settled	(2		)	(2	)	(4	)
Change in estimate	(21		)	(10	)	(3	)
Balance at end of year	$	91		107		106

Severance and Leased Real Estate (Tables)

12 Months Ended

Dec. 31, 2015

Restructuring and Related Activities [Abstract]

Schedule of changes in accrued liabilities for severance expenses and leased real estate

Changes in our accrued liabilities for severance expenses and leased real estate were as follows:



	Severance			Real Estate
	(Dollars in millions)
Balance at December 31, 2013	$	17		113
Accrued to expense	87			1
Payments, net	(78		)	(16	)
Reversals and adjustments	—			(2	)
Balance at December 31, 2014	26			96
Accrued to expense	96			—
Payments, net	(108		)	(13	)
Reversals and adjustments	—			(3	)
Balance at December 31, 2015	$	14		80

Employee Benefits (Tables)

12 Months Ended

Dec. 31, 2015

Dec. 31, 2014

Employee Benefits

Schedule of estimated future benefit payments

The estimated benefit payments provided below are based on actuarial assumptions using the demographics of the employee and retiree populations and have been reduced by estimated participant contributions.



	Pension Plans		Post-Retirement Benefit Plans	Medicare Part D Subsidy Receipts
	(Dollars in millions)
Estimated future benefit payments:
2016	$	1,059	309	(7	)
2017	1,010		300	(7	)
2018	991		290	(7	)
2019	973		283	(7	)
2020	954		276	(7	)
2021 - 2025	4,433		1,256	(30	)

Schedule of actuarial assumptions used to compute net periodic benefit expense

The actuarial assumptions used to compute the net periodic benefit expense for our qualified pension, non-qualified pension and post-retirement benefit plans are based upon information available as of the beginning of the year, as presented in the following table.



	Pension Plans						Post-Retirement Benefit Plans
	2015		2014		2013		2015		2014		2013
Actuarial assumptions at beginning of year:
Discount rate	3.50% - 4.10%		4.20% - 5.10%		3.50% - 4.20%		3.80	%	4.50	%	3.60	%
Rate of compensation increase	3.25	%	3.25	%	3.25	%	N/A		N/A		N/A
Expected long-term rate of return on plan assets	7.50	%	7.50	%	7.50	%	7.50	%	6.00% - 7.50%		6.00% - 7.30%
Initial health care cost trend rate	N/A		N/A		N/A		6.00% / 6.50%		6.00% / 6.50%		6.50% / 7.00%
Ultimate health care cost trend rate	N/A		N/A		N/A		4.50	%	4.50	%	4.50	%
Year ultimate trend rate is reached	N/A		N/A		N/A		2025		2024		2022

_______________________________________________________________________________

N/A-Not applicable

Schedule of actuarial assumptions used to compute the funded status for the plans

The actuarial assumptions used to compute the funded status for the plans are based upon information available as of December 31, 2015 and 2014 and are as follows:



	Pension Plans				Post-Retirement Benefit Plans
	December 31,				December 31,
	2015		2014		2015		2014
Actuarial assumptions at end of year:
Discount rate	3.50% - 4.50%		3.50% - 4.10%		4.15	%	3.80	%
Rate of compensation increase	3.25	%	3.25	%	N/A		N/A
Initial health care cost trend rate	N/A		N/A		5.00% / 5.25%		6.00% / 6.50%
Ultimate health care cost trend rate	N/A		N/A		4.50	%	4.50	%
Year ultimate trend rate is reached	N/A		N/A		2025		2024

_______________________________________________________________________________

N/A-Not applicable

Schedule of change in plan assets

The following tables summarize the change in the fair value of plan assets for the pension and post-retirement benefit plans:



	Pension Plans Years Ended December 31,
	2015			2014		2013
	(Dollars in millions)
Change in plan assets
Fair value of plan assets at beginning of year	$	12,571		12,346		12,321
Return on plan assets	(161		)	1,373		810
Employer contributions	100			157		146
Settlements	—			(460	)	—
Benefits paid from plan assets	(1,438		)	(845	)	(931	)
Fair value of plan assets at end of year	$	11,072		12,571		12,346

Schedule of gross notional exposure of the derivative instruments directly held by the plans

The gross notional exposure of the derivative instruments directly held by the plans is shown below. The notional amount of the derivatives corresponds to market exposure but does not represent an actual cash investment.



	Gross Notional Exposure
	Pension Plans			Post-Retirement Benefit Plans
	Years Ended December 31,
	2015		2014	2015	2014
	(Dollars in millions)
Derivative instruments:
Exchange-traded U.S. equity futures	$	79	134	—	7
Exchange-traded Treasury and other interest rate futures	1,767		2,451	—	—
Interest rate swaps	550		579	—	—
Credit default swaps	189		382	—	—
Foreign exchange forwards	992		1,195	—	13
Options	285		529	—	—

Schedule of the unfunded status of the benefit plans

The following table presents the unfunded status of the pensions and post-retirement benefit plans:



	Pension Plans					Post-Retirement Benefit Plans
	Years Ended December 31,					Years Ended December 31,
	2015			2014		2015		2014
	(Dollars in millions)
Benefit obligation	$	(13,349	)	(15,042	)	(3,567	)	(3,830	)
Fair value of plan assets	11,072			12,571		193		353
Unfunded status	(2,277		)	(2,471	)	(3,374	)	(3,477	)
Current portion of unfunded status	$	(5	)	(6	)	(135	)	(134	)
Non-current portion of unfunded status	$	(2,272	)	(2,465	)	(3,239	)	(3,343	)

Schedule of items not recognized as a component of net periodic benefits expense

The items not recognized as a component of net periodic benefits expense have been recorded on our consolidated balance sheets in accumulated other comprehensive loss:



	As of and for the Years Ended December 31,
	2014			Recognition of Net Periodic Benefits Expense		Deferrals		Net Change in AOCL		2015
	(Dollars in millions)
Accumulated other comprehensive loss:
Pension plans:
Net actuarial (loss) gain	$	(2,760	)	161		(258	)	(97	)	(2,857	)
Prior service (cost) benefit	(32		)	5		99		104		72
Deferred income tax benefit (expense)	1,072			(63	)	61		(2	)	1,070
Total pension plans	(1,720		)	103		(98	)	5		(1,715	)
Post-retirement benefit plans:
Net actuarial (loss) gain	(277		)	—		130		130		(147	)
Prior service (cost) benefit	(166		)	19		—		19		(147	)
Deferred income tax benefit (expense)	171			(7	)	(50	)	(57	)	114
Total post-retirement benefit plans	(272		)	12		80		92		(180	)
Total accumulated other comprehensive loss	$	(1,992	)	115		(18	)	97		(1,895	)

Schedule of estimated items to be recognized in 2013 as a component of net periodic benefit expense

The following table presents estimated items to be recognized in 2016 as a component of net periodic benefit expense of the pension, non-qualified pension and post-retirement benefit plans:



	Pension Plans			Post-Retirement Plans
	(Dollars in millions)
Estimated recognition of net periodic benefit (cost)/income in 2016:
Net actuarial loss	$	(168	)	—
Prior service (cost)/income	8			(20	)
Deferred income tax benefit	61			8
Estimated net periodic benefit expense to be recorded in 2016 as a component of other comprehensive income (loss)	$	(99	)	(12	)

Pension Plan

Employee Benefits

Schedule of components of net periodic pension income and post-retirement benefit expense

Net periodic (income) expense for our qualified and non-qualified pension plans includes the following components:



	Pension Plans Years Ended December 31,
	2015			2014		2013
	(Dollars in millions)
Service cost	$	83		77		91
Interest cost	568			602		544
Expected return on plan assets	(898		)	(891	)	(896	)
Settlements	—			63		—
Recognition of prior service cost	5			5		5
Recognition of actuarial loss	161			22		84
Net periodic pension benefit income	$	(81	)	(122	)	(172	)

Schedule of change in benefit obligation

The following tables summarize the change in the benefit obligations for the pension and post-retirement benefit plans:



	Pension Plans Years Ended December 31,
	2015			2014		2013
	(Dollars in millions)
Change in benefit obligation
Benefit obligation at beginning of year	$	15,042		13,401		14,881
Service cost	83			77		91
Interest cost	568			602		544
Plan amendments	(100		)	4		—
Actuarial loss (gain)	(800		)	2,269		(1,179	)
Settlements	—			(460	)	—
Benefits paid by company	(6		)	(6	)	(5	)
Benefits paid from plan assets	(1,438		)	(845	)	(931	)
Benefit obligation at end of year	$	13,349		15,042		13,401

Schedule of change in plan assets



	Post-Retirement Benefit Plans Years Ended December 31,
	2015			2014		2013
	(Dollars in millions)
Change in plan assets
Fair value of plan assets at beginning of year	$	353		535		626
Return on plan assets	3			37		45
Benefits paid from plan assets	(163		)	(219	)	(136	)
Fair value of plan assets at end of year	$	193		353		535

Schedule of fair value of the plans' assets by asset category

The tables below present the fair value of plan assets by category and the input levels used to determine those fair values at December 31, 2015. It is important to note that the asset allocations do not include market exposures that are gained with derivatives. Investments include dividend and interest receivables, pending trades and accrued expenses.



	Fair Value of Pension Plan Assets at December 31, 2015
	Level 1		Level 2		Level 3	Total
	(Dollars in millions)
Investment grade bonds (a)	$	841	1,045		—	$	1,886
High yield bonds (b)	—		544		13	557
Emerging market bonds (c)	208		232		1	441
Convertible bonds (d)	—		2		—	2
U.S. stocks (f)	1,201		—		—	1,201
Non-U.S. stocks (g)	1,127		1		—	1,128
Multi-asset strategies (m)	376		—		—	376
Derivatives (n)	2		(6	)	—	(4		)
Cash equivalents and short-term investments (o)	—		192		—	192
Total investments, excluding investments valued at NAV	$	3,755	2,010		14	5,779
Investments valued at NAV						5,293
Total pension plan assets						$	11,072

The tables below present the fair value of plan assets by category and the input levels used to determine those fair values at December 31, 2014. It is important to note that the asset allocations do not include market exposures that are gained with derivatives. Investments include dividend and interest receivable, pending trades and accrued expenses.



	Fair Value of Pension Plan Assets at December 31, 2014
	Level 1		Level 2	Level 3	Total
	(Dollars in millions)
Investment grade bonds (a)	$	1,068	1,278	—	$	2,346
High yield bonds (b)	—		647	7	654
Emerging market bonds (c)	208		407	—	615
Convertible bonds (d)	—		4	—	4
U.S. stocks (f)	1,389		1	—	1,390
Non-U.S. stocks (g)	1,169		1	—	1,170
Derivatives (n)	2		15	—	17
Cash equivalents and short-term investments (o)	—		626	—	626
Total investments, excluding investments valued at NAV	$	3,836	2,979	7	6,822
Investments valued at NAV					5,749
Total pension plan assets					$	12,571

Summary of changes in fair value of defined benefit plans' Level 3 assets

The table below presents a rollforward of the pension plan assets valued using Level 3 inputs:



	Pension Plan Assets Valued Using Level 3 Inputs
	High Yield Bonds			Emerging Market Bonds	Total
	(Dollars in millions)
Balance at December 31, 2013	$	—		—	—
Net transfers	6			—	6
Acquisitions	1			—	1
Dispositions	(3		)	—	(3	)
Actual return on plan assets:
Gains relating to assets sold during the year	4			—	4
(Losses) gains relating to assets still held at year-end	(1		)	—	(1	)
Balance at December 31, 2014	7			—	7
Net transfers	4			1	5
Acquisitions	4			—	4
Dispositions	(2		)	—	(2	)
Actual return on plan assets:
Gains relating to assets sold during the year	—			—	—
(Losses) gains relating to assets still held at year-end	—			—	—
Balance at December 31, 2015	$	13		1	14

Post-Retirement Benefit Plans

Employee Benefits

Schedule of effects of a 100 basis point change in assumed health care cost rates

A change of 100 basis points in the assumed initial health care cost trend rate would have had the following effects in 2015:



	100 Basis Points Change
	Increase		(Decrease)
	(Dollars in millions)
Effect on the aggregate of the service and interest cost components of net periodic post-retirement benefit expense (consolidated statement of operations)	$	3	(3	)
Effect on benefit obligation (consolidated balance sheet)	73		(68	)

Schedule of components of net periodic pension income and post-retirement benefit expense

Net periodic expense (income) for our post-retirement benefit plans includes the following components:



	Post-Retirement Plans Years Ended December 31,
	2015			2014		2013
	(Dollars in millions)
Service cost	$	24		22		24
Interest cost	140			159		140
Expected return on plan assets	(21		)	(33	)	(39	)
Recognition of prior service cost	19			20		—
Recognition of actuarial loss	—			—		4
Net periodic post-retirement benefit expense	$	162		168		129

Schedule of change in benefit obligation



	Post-Retirement Benefit Plans Years Ended December 31,
	2015			2014		2013
	(Dollars in millions)
Change in benefit obligation
Benefit obligation at beginning of year	$	3,830		3,688		4,075
Service cost	24			22		24
Interest cost	140			159		140
Participant contributions	57			69		96
Plan amendments	—			23		141
Direct subsidy receipts	8			9		13
Actuarial loss (gain)	(148		)	245		(399	)
Benefits paid by company	(181		)	(166	)	(266	)
Benefits paid from plan assets	(163		)	(219	)	(136	)
Benefit obligation at end of year	$	3,567		3,830		3,688

Schedule of fair value of the plans' assets by asset category



	Fair Value of Post-Retirement Plan Assets at December 31, 2015
	Level 1		Level 2	Level 3	Total
	(Dollars in millions)
Investment grade bonds (a)	$	2	1	—	$	3
High yield bonds (b)	—		1	—	1
U.S. stocks (f)	16		—	—	16
Non-U.S. stocks (g)	12		—	—	12
Emerging market stocks (h)	4		—	—	4
Cash equivalents and short-term investments (o)	—		4	—	4
Total investments, excluding investments valued at NAV	$	34	6	—	40
Investments valued at NAV					153
Total post-retirement plan assets					$	193



	Fair Value of Post-Retirement Plan Assets at December 31, 2014
	Level 1		Level 2	Level 3	Total
	(Dollars in millions)
Investment grade bonds (a)	$	5	1	—	$	6
High yield bonds (b)	—		1	—	1
U.S. stocks (f)	35		—	—	35
Non-U.S. stocks (g)	33		—	—	33
Emerging market stocks (h)	6		—	—	6
Cash equivalents and short-term investments (o)	—		8	—	8
Total investments, excluding investments valued at NAV	$	79	10	—	89
Investments valued at NAV					264
Total post-retirement plan assets					$	353

Pension, Supplemental And Other Postretirement Benefit Plans [Member]

Employee Benefits

Schedule of fair value of the plans' assets by asset category

The table below presents the fair value of plan assets valued at NAV by category for our pension and post-retirement plans at December 31, 2015 and 2014. See Note 1 - Basis of Presentation and Summary of Significant Accounting Policies for additional information regarding the 2015 adoption of ASU 2015-07.



	Fair Value of Plan Assets Valued at NAV
	Pension Plans at December 31,			Post-Retirement Benefit Plans at December 31,
	2015		2014	2015	2014
	(Dollars in millions)
Investment grade bonds (a)	$	115	148	35	71
High yield bonds (b)	512		860	1	14
Emerging market bonds (c)	9		27	—	—
Convertible bonds (d)	—		10	—	—
Diversified strategies (e)	516		718	54	89
U.S. stocks (f)	70		86	—	—
Non-U.S. stocks (g)	289		384	—	—
Emerging market stocks (h)	64		102	—	—
Private equity (i)	526		673	21	28
Private debt (j)	371		394	2	3
Market neutral hedge funds (k)	825		1,026	17	25
Directional hedge funds (k)	594		558	1	1
Real estate (l)	968		699	20	28
Multi-asset strategies (m)	386		—	—	—
Cash equivalents and short-term investments (o)	48		64	2	5
Total investments valued at NAV	$	5,293	5,749	153	264

Share-based Compensation (Tables)

12 Months Ended

Dec. 31, 2015

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Stock option awards activity

The following table summarizes activity involving stock option awards for the year ended December 31, 2015:



	Number of Options		Weighted- Average Exercise Price
	(in thousands)
Outstanding and Exercisable at December 31, 2014	4,106		$	37.99
Exercised	(335	)	26.00
Forfeited/Expired	(246	)	30.33
Outstanding and Exercisable at December 31, 2015	3,525		39.67

Restricted stock and restricted stock unit awards activity

The following table summarizes activity involving restricted stock and restricted stock unit awards for the year ended December 31, 2015:



	Number of Shares		Weighted- Average Grant Date Fair Value
	(in thousands)
Non-vested at December 31, 2014	4,400		$	36.59
Granted	2,904		31.83
Vested	(1,724	)	35.71
Forfeited	(678	)	38.95
Non-vested at December 31, 2015	4,902		33.86

Earnings (Loss) Per Common Share (Tables)

12 Months Ended

Dec. 31, 2015

Earnings Per Share [Abstract]

Schedule of basic and diluted earnings per common share

Basic and diluted earnings (loss) per common share for the years ended December 31, 2015, 2014 and 2013 were calculated as follows:



	Years Ended December 31,
	2015			2014		2013
	(Dollars in millions, except per share amounts, shares in thousands)
Income (Loss) (Numerator):
Net income (loss)	$	878		772		(239	)
Earnings applicable to non-vested restricted stock	—			—		—
Net income (loss) applicable to common stock for computing basic earnings (loss) per common share	878			772		(239	)
Net income (loss) as adjusted for purposes of computing diluted earnings (loss) per common share	$	878		772		(239	)
Shares (Denominator):
Weighted average number of shares:
Outstanding during period	559,260			572,748		604,404
Non-vested restricted stock	(4,982		)	(4,313	)	(3,512	)
Weighted average shares outstanding for computing basic earnings (loss) per common share	554,278			568,435		600,892
Incremental common shares attributable to dilutive securities:
Shares issuable under convertible securities	10			10		—
Shares issuable under incentive compensation plans	805			1,294		—
Number of shares as adjusted for purposes of computing diluted earnings (loss) per common share	555,093			569,739		600,892
Basic earnings (loss) per common share	$	1.58		1.36		(0.40	)
Diluted earnings (loss) per common share	$	1.58		1.36		(0.40	)

Our calculation of diluted

Fair Value Disclosure (Tables)

12 Months Ended

Dec. 31, 2015

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 indicated below:



		As of December 31, 2015			As of December 31, 2014
	Input Level	Carrying Amount		Fair Value	Carrying Amount	Fair Value
		(Dollars in millions)
Liabilities-Long-term debt excluding capital lease and other obligations	2	$	19,800	19,473	19,994	21,255

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2015

Income Tax Disclosure [Abstract]

Schedule of components of provision for income tax



	Years Ended December 31,
	2015		2014		2013
	(Dollars in millions)
Income tax expense was as follows:
Federal
Current	$	28	18		1
Deferred	329		305		403
State
Current	40		26		62
Deferred	21		(14	)	(8	)
Foreign
Current	16		3		9
Deferred	4		—		(4	)
Total income tax expense	$	438	338		463

Schedule of income tax expense allocation



	Years Ended December 31,
	2015			2014		2013
	(Dollars in millions)
Income tax expense was allocated as follows:
Income tax expense in the consolidated statements of operations:
Attributable to income	$	438		338		463
Stockholders' equity:
Compensation expense for tax purposes in excess of amounts recognized for financial reporting purposes	(5		)	(5	)	(14	)
Tax effect of the change in accumulated other comprehensive loss	59			(744	)	554

Schedule of reconciliation of the statutory federal income tax rate to effective income tax rate

The following is a reconciliation from the statutory federal income tax rate to our effective income tax rate:



	Years Ended December 31,
	2015		2014		2013
	(Percentage of pre-tax income)
Statutory federal income tax rate	35.0	%	35.0	%	35.0	%
State income taxes, net of federal income tax benefit	2.6	%	2.7	%	2.8	%
Impairment of goodwill	—	%	—	%	188.5	%
Change in liability for unrecognized tax position	0.4	%	0.4	%	(24.5	)%
Foreign income taxes	0.7	%	0.4	%	2.7	%
Nondeductible accounting adjustment for life insurance	—	%	—	%	3.1	%
Affiliate debt rationalization	(2.6	)%	—	%	—	%
Release state valuation allowance	—	%	—	%	(2.3	)%
Research and development credits	(2.1	)%	—	%	—	%
Loss on worthless investment in foreign subsidiary	—	%	(5.4	)%	—	%
Other, net	(0.7	)%	(2.6	)%	1.4	%
Effective income tax rate	33.3	%	30.5	%	206.7	%

Schedule of components of deferred tax assets and deferred tax 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,
	2015			2014
	(Dollars in millions)
Deferred tax assets
Post-retirement and pension benefit costs	$	2,154		2,276
Net operating loss carryforwards	487			1,091
Other employee benefits	182			214
Other	458			602
Gross deferred tax assets	3,281			4,183
Less valuation allowance	(380		)	(409	)
Net deferred tax assets	2,901			3,774
Deferred tax liabilities
Property, plant and equipment, primarily due to depreciation differences	(3,841		)	(3,869	)
Goodwill and other intangible assets	(2,588		)	(2,908	)
Other	(38		)	(147	)
Gross deferred tax liabilities	(6,467		)	(6,924	)
Net deferred tax liability	$	(3,566	)	(3,150	)

Summary of the reconciliation of the change in gross unrecognized tax benefits

A reconciliation of the change in our gross unrecognized tax benefits (excluding both interest and any related federal benefit) from January 1 to December 31 for 2015 and 2014 is as follows:



	2015			2014
	(Dollars in millions)
Unrecognized tax benefits at beginning of year	$	17		14
Increase in tax positions taken in the current year	1			—
Increase in tax positions taken in the prior year	7			9
Decrease due to the reversal of tax positions taken in a prior year	(9		)	(2	)
Decrease from the lapse of statute of limitations	(1		)	(1	)
Settlements	—			(3	)
Unrecognized tax benefits at end of year	$	15		17

Schedule of open income tax years by major jurisdiction

Our open income tax years by major jurisdiction are as follows at December 31, 2015:



Jurisdiction		Open Tax Years
Federal		2012—current
State
Arizona		2010—current
Florida		2010—current
Other states		2011—current

Segment Information (Tables)

12 Months Ended

Dec. 31, 2015

Segment Reporting [Abstract]

Schedule of segment information

The following table summarizes our segment results for 2015, 2014 and 2013 based on the segment categorization we were operating under at December 31, 2015.



	Years Ended December 31,
	2015			2014		2013
	(Dollars in millions)
Total segment revenues	$	16,668		17,028		17,095
Total segment expenses	8,459			8,509		8,167
Total segment income	$	8,209		8,519		8,928
Total margin percentage	49		%	50	%	52	%
Business segment:
Revenues	$	10,647		11,034		11,091
Expenses	6,034			6,089		5,808
Income	$	4,613		4,945		5,283
Margin percentage	43		%	45	%	48	%
Consumer segment:
Revenues	$	6,021		5,994		6,004
Expenses	2,425			2,420		2,359
Income	$	3,596		3,574		3,645
Margin percentage	60		%	60	%	61	%

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, 2015, 2014 and 2013:



	Years Ended December 31,
	2015		2014	2013
	(Dollars in millions)
Strategic services
Business high-bandwidth data services (1)	$	2,816	2,579	2,230
Business low-bandwidth data services (2)	2,052		2,345	2,577
Business hosting services (3)	1,281		1,316	1,259
Other business strategic services (4)	162		76	60
Consumer high-speed Internet services (5)	2,611		2,469	2,358
Other consumer strategic services (6)	421		381	292
Total strategic services revenues	9,343		9,166	8,776

Legacy services
Business legacy voice services (7)	2,590		2,780	2,916
Other business legacy services (8)	1,175		1,252	1,398
Consumer legacy voice services (7)	2,676		2,864	3,101
Other consumer legacy services (9)	311		276	248
Total legacy services revenues	6,752		7,172	7,663

Data integration
Business data integration	571		686	651
Consumer data integration	2		4	5
Total data integration revenues	573		690	656

Other revenues
High-cost support revenue (10)	732		528	547
Other revenue (11)	500		475	453
Total other revenues	1,232		1,003	1,000

Total revenues	$	17,900	18,031	18,095

Schedule of reconciliation from segment income to consolidated net income

The following table reconciles segment income to net income for the years ended December 31, 2015, 2014 and 2013:



	Years Ended December 31,
	2015			2014		2013
	(Dollars in millions)
Total segment income	$	8,209		8,519		8,928
Other operating revenues	1,232			1,003		1,000
Depreciation and amortization	(4,189		)	(4,428	)	(4,541	)
Impairment of goodwill	—			—		(1,092	)
Other unassigned operating expenses	(2,647		)	(2,684	)	(2,842	)
Other expenses, net	(1,289		)	(1,300	)	(1,229	)
Income tax expense	(438		)	(338	)	(463	)
Net income (loss)	$	878		772		(239	)

Quarterly Financial Data (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2015

Quarterly Financial Information Disclosure [Abstract]

Schedule of quarterly financial information



	First Quarter		Second Quarter	Third Quarter	Fourth Quarter	Total
	(Dollars in millions, except per share amounts)
2015
Operating revenues	$	4,451	4,419	4,554	4,476	17,900
Operating income	649		549	656	751	2,605
Net income	192		143	205	338	878
Basic earnings per common share	0.34		0.26	0.37	0.62	1.58
Diluted earnings per common share	0.34		0.26	0.37	0.62	1.58
2014
Operating revenues	$	4,538	4,541	4,514	4,438	18,031
Operating income	653		655	619	483	2,410
Net income	203		193	188	188	772
Basic earnings per common share	0.35		0.34	0.33	0.33	1.36
Diluted earnings per common share	0.35		0.34	0.33	0.33	1.36

Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2015

Commitments and Contingencies Disclosure [Abstract]

Schedule of capital lease activity

The tables below summarize our capital lease activity:



	Years Ended December 31,
	2015		2014	2013
	(Dollars in millions)
Assets acquired through capital leases	$	17	37	12
Depreciation expense	96		126	136
Cash payments towards capital leases	89		118	119



	As of December 31,
	2015		2014
	(Dollars in millions)
Assets included in property, plant and equipment	$	722	850
Accumulated depreciation	352		393

Schedule of future annual minimum payments under capital lease arrangements

The future annual minimum payments under capital lease arrangements as of December 31, 2015 were as follows:



	Future Minimum Payments
	(Dollars in millions)
Capital lease obligations:
2016	$	85
2017	78
2018	76
2019	62
2020	47
2021 and thereafter	223
Total minimum payments	571
Less: amount representing interest and executory costs	(153		)
Present value of minimum payments	418
Less: current portion	(56		)
Long-term portion	$	362

Schedule of future rental commitments for operating leases

At December 31, 2015, our future rental commitments for operating leases were as follows:



	Future Minimum Payments
	(Dollars in millions)
2016	$	301
2017	289
2018	268
2019	235
2020	209
2021 and thereafter	1,075
Total future minimum payments ⁽¹⁾	$	2,377

_______________________________________________________________________________


⁽¹⁾	Minimum payments have not been reduced by minimum sublease rentals of $87 million due in the future under non-cancelable subleases.

Other Financial Information (Tables)

12 Months Ended

Dec. 31, 2015

Additional Financial Information Disclosure [Abstract]

Schedule of components of other current assets

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



	As of December 31,
	2015		2014
	(Dollars in millions)
Prepaid expenses	$	238	260
Materials, supplies and inventory	144		132
Assets held for sale	8		14
Deferred activation and installation charges	105		103
Other	86		71
Total other current assets	$	581	580

Schedule of current liabilities including accounts payable and other current liabiities

Current liabilities reflected in our consolidated balance sheets include accounts payable and other current liabilities as follows:



	As of December 31
	2015		2014
	(Dollars in millions)
Accounts payable	$	968	1,226
Other current liabilities:
Accrued rent	$	32	34
Legal reserves	20		27
Other	168		149
Total other current liabilities	$	220	210

Accumulated Other Comprehensive Loss (Tables)

12 Months Ended

Dec. 31, 2015

Dec. 31, 2014

Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]

Summary of the entity's accumulated other comprehensive income (loss) by component

The table below summarizes changes in accumulated other comprehensive loss recorded on our consolidated balance sheet by component for the year ended December 31, 2015:



	Pension Plans			Post-Retirement Benefit Plans		Foreign Currency Translation Adjustment and Other		Total
	(Dollars in millions)
Balance at December 31, 2014	$	(1,720	)	(272	)	(25	)	(2,017	)
Other comprehensive income (loss) before reclassifications	(98		)	80		(14	)	(32	)
Amounts reclassified from accumulated other comprehensive income	103			12		—		115
Net current-period other comprehensive income (loss)	5			92		(14	)	83
Balance at December 31, 2015	$	(1,715	)	(180	)	(39	)	(1,934	)

The table below summarizes changes in accumulated other comprehensive loss recorded on our consolidated balance sheet by component for the year ended December 31, 2014:



	Pension Plans			Post-Retirement Benefit Plans		Foreign Currency Translation Adjustment and Other		Total
	(Dollars in millions)
Balance at December 31, 2013	$	(669	)	(122	)	(11	)	(802	)
Other comprehensive income (loss) before reclassifications	(1,107		)	(162	)	(15	)	(1,284	)
Amounts reclassified from accumulated other comprehensive income	56			12		1		69
Net current-period other comprehensive income (loss)	(1,051		)	(150	)	(14	)	(1,215	)
Balance at December 31, 2014	$	(1,720	)	(272	)	(25	)	(2,017	)

Schedule of reclassifications out of accumulated other comprehensive income (loss) by component

The table below presents further information about our reclassifications out of accumulated other comprehensive loss by component for the year ended December 31, 2015:



Year Ended December 31, 2015	Decrease (Increase) in Net Income			Affected Line Item in Consolidated Statement of Operations or Footnote Where Additional Information is Presented If The Amount is not Recognized in Net Income in Total
	(Dollars in millions)
Amortization of pension & post-retirement plans
Net actuarial loss	$	161		See Note 7—Employee Benefits
Prior service cost	24			See Note 7—Employee Benefits
Total before tax	185
Income tax expense (benefit)	(70		)	Income tax expense
Net of tax	$	115

The table below presents further information about our reclassifications out of accumulated other comprehensive loss by component for the year ended December 31, 2014:



Year Ended December 31, 2014	Decrease (Increase) in Net Loss			Affected Line Item in Consolidated Statement of Operations or Footnote Where Additional Information is Presented If The Amount is not Recognized in Net Income in Total
	(Dollars in millions)
Amortization of pension & post-retirement plans
Net actuarial loss	$	85		See Note 7—Employee Benefits
Prior service cost	25			See Note 7—Employee Benefits
Total before tax	110
Income tax expense (benefit)	(42		)	Income tax expense
Insignificant items	1
Net of tax	$	69

Dividends (Tables)

12 Months Ended

Dec. 31, 2015

Dividends, Common Stock [Abstract]

Schedule of dividends declared

Our Board of Directors declared the following dividends payable in 2015 and 2014:

Date Declared

Record Date

Dividend

Per Share

Total Amount

Payment Date

(in millions)

November 10, 2015

11/24/2015

$

0.540

$

293

12/8/2015

August 25, 2015

9/8/2015

0.540

300

9/22/2015

May 20, 2015

6/2/2015

0.540

303

6/16/2015

February 23, 2015

3/6/2015

0.540

303

3/20/2015

November 11, 2014

11/24/2014

0.540

307

12/5/2014

August 19, 2014

8/29/2014

0.540

308

9/12/2014

May 28, 2014

6/9/2014

0.540

307

6/20/2014

February 24, 2014

3/10/2014

0.540

309

3/21/2014

Basis of Presentation and Summary of Significant Accounting Policies Basis of Presentation and Summary of Significant Accounting Policies (Details) $ in Millions		3 Months Ended		12 Months Ended
	Aug. 27, 2015 USD ($)	Dec. 31, 2015 USD ($) state	Sep. 30, 2015 USD ($)	Dec. 31, 2015 USD ($) state
Operating revenues by products and services
Incremental increase in other operating revenues		$ 57	$ 158
CAF Phase 2 Support [Member]
Operating revenues by products and services
Federal support, total amount per agreement	$ 500
Contract or agreement term	6
Number of rural households and businesses	1,200,000
Number of states in which service is provided (states) \| state		33		33
Incremental increase in other operating revenues				$ 215

Basis of Presentation and Summary of Significant Accounting Policies (Details 2) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Change in accounting estimates
Depreciation									$ 2,836	$ 2,958	$ 2,952
Net income (loss)	$ 338	$ 205	$ 143	$ 192	$ 188	$ 188	$ 193	$ 203	878	772	$ (239)
Service life \| Switch, circuit and cable network equipment
Change in accounting estimates
Depreciation										78
Net income (loss)										$ 48
Earnings per share, basic and diluted										$ 0.08
Service life \| Network assets, future abandonment
Change in accounting estimates
Depreciation									48	$ 12
Net income (loss)									$ 32	$ 7
Earnings per share, basic and diluted									$ 0.06	$ 0.01

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References + Details

Basis of Presentation and Summary of Significant Accounting Policies Basis of Presentation and Summary of Significant Accounting Policies (Details 3) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenue Recognition
Term of indefeasible rights of use (in years)	20 years
Advertising Costs
Advertising expense	$ 210	$ 214	$ 210
Accounts Receivable and Allowance for Doubtful Accounts
Period of accounts past due	30 days
Activation and installation charges \| Minimum
Revenue Recognition
Customer relationship period for revenue recognition (from eighteen months to over ten years)	18 months
Activation and installation charges \| Maximum
Revenue Recognition
Customer relationship period for revenue recognition (from eighteen months to over ten years)	10 years

Basis of Presentation and Summary of Significant Accounting Policies (Details 4) $ in Millions	12 Months Ended
	Dec. 31, 2015 USD ($)
Customer relationships \| Minimum
Finite-Lived Intangible Assets [Line Items]
Estimated useful life	10 years
Customer relationships \| Maximum
Finite-Lived Intangible Assets [Line Items]
Estimated useful life	15 years
Capitalized software
Finite-Lived Intangible Assets [Line Items]
Estimated useful life	7 years
Integrated billing and customer care system
Finite-Lived Intangible Assets [Line Items]
Estimated useful life	20 years
Finite-lived intangible assets, gross	$ 237
Other
Finite-Lived Intangible Assets [Line Items]
Estimated useful life	4 years

Basis of Presentation and Summary of Significant Accounting Policies (Details 5) shares in Millions	Dec. 31, 2015 $ / shares shares
Common Stock
Class of Stock [Line Items]
Unissued shares of CenturyLink common stock	4
Common Stock \| Stock compensation plan
Class of Stock [Line Items]
Unissued shares of CenturyLink common stock	25
Preferred Stock
Class of Stock [Line Items]
Preferential preferred stock distribution (in dollars per share) \| $ / shares	$ 25

Basis of Presentation and Summary of Significant Accounting Policies Basis of Presentation and Sumnary of Significant Accounting Policies (Details 6) - USD ($) $ / shares in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
New Accounting Pronouncement, Early Adoption [Line Items]
Net income (loss)	$ 338,000,000	$ 205,000,000	$ 143,000,000	$ 192,000,000	$ 188,000,000	$ 188,000,000	$ 193,000,000	$ 203,000,000	$ 878,000,000	$ 772,000,000	$ (239,000,000)
Total current assets	(2,650,000,000)				(2,696,000,000)				(2,650,000,000)	(2,696,000,000)
Other, net	(660,000,000)				(679,000,000)				(660,000,000)	(679,000,000)
Long-term debt	(18,722,000,000)				(19,953,000,000)				(18,722,000,000)	(19,953,000,000)
Deferred income taxes, net	(3,569,000,000)				(3,154,000,000)				(3,569,000,000)	(3,154,000,000)
Pension Plan
New Accounting Pronouncement, Early Adoption [Line Items]
Fair value of plan assets valued at NAV	5,293,000,000				5,749,000,000				5,293,000,000	5,749,000,000
Fair value of plan assets	11,072,000,000				12,571,000,000				11,072,000,000	12,571,000,000	12,346,000,000	$ 12,321,000,000
Post-Retirement Benefit Plans
New Accounting Pronouncement, Early Adoption [Line Items]
Fair value of plan assets valued at NAV	153,000,000				264,000,000				153,000,000	264,000,000
Fair value of plan assets	$ 193,000,000				353,000,000				$ 193,000,000	353,000,000	535,000,000	$ 626,000,000
Restatement adjustment \| New Accounting Pronouncement, Early Adoption, Effect
New Accounting Pronouncement, Early Adoption [Line Items]
Net income (loss)										$ 0	$ 0
Earnings per share, basic and diluted										$ 0	$ 0
Total current assets					880,000,000					$ 880,000,000
Other, net					164,000,000					164,000,000
Long-term debt					168,000,000					168,000,000
Deferred income taxes, net					876,000,000					876,000,000
Net cash provided by operating activities										0	$ 0
Restatement adjustment \| New Accounting Pronouncement, Early Adoption, Effect \| Pension Plan
New Accounting Pronouncement, Early Adoption [Line Items]
Fair value of plan assets					0					0
Restatement adjustment \| New Accounting Pronouncement, Early Adoption, Effect \| Post-Retirement Benefit Plans
New Accounting Pronouncement, Early Adoption [Line Items]
Fair value of plan assets					$ 0					$ 0

Goodwill, Customer Relationships and Other Intangible Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Finite-Lived Intangible Assets [Line Items]
Other intangible assets, net	$ 1,555	$ 1,647
Goodwill	20,742	20,755	$ 20,674
Indefinite-life intangible assets	269	268
Amortization expense for intangible assets	1,353	1,470	$ 1,589
Gross carrying amount of intangible assets	33,671
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Finite lived intangible assets, net	3,928	4,893
Accumulated amortization	5,648	4,683
Capitalized software
Finite-Lived Intangible Assets [Line Items]
Finite lived intangible assets, net	1,248	1,338
Accumulated amortization	1,778	1,533
Tradenames and patents
Finite-Lived Intangible Assets [Line Items]
Finite lived intangible assets, net	38	41
Accumulated amortization	$ 20	$ 196

Goodwill, Customer Relationships and Other Intangible Assets (Details 2) $ in Millions	Dec. 31, 2015 USD ($)
Expected amortization expense
2016	$ 1,161
2017	1,056
2018	944
2019	827
2020	$ 726

Goodwill, Customer Relationships and Other Intangible Assets Goodwill, Customer Relationships and Other Intangible Assets (Details 3) $ in Millions				12 Months Ended
	Oct. 31, 2015	Oct. 31, 2014	Sep. 30, 2013	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Goodwill [Line Items]
Percentage of reasonable implied control premium (percent)				24.60%
Number of reporting units	3	4	1
Impairment of goodwill				$ 0	$ 0	$ 1,092
Consumer and Wholesale reportable units
Goodwill [Line Items]
Discount rate (percent)	6.00%
Fair value inputs after tax cost of debt rate (percent)	3.30%
Fair value inputs cost of equity rate (percent)	7.60%
Business reporting unit
Goodwill [Line Items]
Discount rate (percent)	7.00%
Fair value inputs after tax cost of debt rate (percent)	3.30%
Fair value inputs cost of equity rate (percent)	8.60%

Goodwill, Customer Relationships and Other Intangible Assets (Details 4) - USD ($) $ in Millions		12 Months Ended
	Nov. 01, 2014	Dec. 31, 2015	Dec. 31, 2014
Goodwill [rollforward]
Goodwill at the beginning of the period		$ 20,755	$ 20,674
Purchase accounting adjustments		(13)	(11)
November 1, 2014 reorganization	$ 0
Acquisitions			92
Goodwill at the end of the period		20,742	20,755
Business
Goodwill [rollforward]
Goodwill at the beginning of the period		10,477	6,363
Purchase accounting adjustments		(13)	0
November 1, 2014 reorganization	4,022
Acquisitions			92
Goodwill at the end of the period		10,464	10,477
Consumer
Goodwill [rollforward]
Goodwill at the beginning of the period		10,278	10,348
Purchase accounting adjustments		0	0
November 1, 2014 reorganization	(70)
Acquisitions			0
Goodwill at the end of the period		10,278	10,278
Wholesale
Goodwill [rollforward]
Goodwill at the beginning of the period		0	3,274
Purchase accounting adjustments		0	0
November 1, 2014 reorganization	(3,274)
Acquisitions			0
Goodwill at the end of the period		0	0
Hosting
Goodwill [rollforward]
Goodwill at the beginning of the period		0	689
Purchase accounting adjustments		0	(11)
November 1, 2014 reorganization	$ (678)
Acquisitions			0
Goodwill at the end of the period		$ 0	$ 0

Goodwill, Customer Relationships and Other Intangible Assets Goodwill, Customer Relationships and Other Intangible Assets (Details 5) $ in Millions	12 Months Ended
	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Business Acquisition [Line Items]
Goodwill acquired during period		$ 92
Goodwill purchase accounting adjustment	$ (13)	$ (11)
Various Business Acquisitions [Member]
Business Acquisition [Line Items]
Number of businesses acquired		2
Payments to acquire businesses, net of cash acquired		$ 95
Cash acquired from business acquisition		2
Goodwill acquired during period		$ 92
Goodwill purchase accounting adjustment	(14)
Finite-Lived intangible assets purchase accounting adjustment	13
Deferred tax assets purchase accounting adjustment	$ (1)

Long-Term Debt and Credit Facilities (Details) - USD ($)
$ in Millions

Dec. 31, 2015

Dec. 31, 2014

Long-term Debt and Credit Facilities

Capital lease and other obligations

$ 425

$ 509

Total long-term debt

^[1]

20,529

Unamortized premiums, discounts and other, net

125

111

Unamortized Debt Issuance Expense

(179)

(168)

Total long-term debt

20,225

20,503

Current maturities of long-term debt

(1,503)

(550)

Long-term debt, excluding current maturities

18,722

19,953

CenturyLink, Inc. | Senior notes

Long-term Debt and Credit Facilities

Total long-term debt

7,975

7,825

CenturyLink, Inc. | Credit facility

Long-term Debt and Credit Facilities

Total long-term debt

$ 410

$ 725

Weighted average interest rate (as a percent)

2.756%

2.27%

CenturyLink, Inc. | Medium-term notes

Long-term Debt and Credit Facilities

Total long-term debt

$ 358

$ 380

Term loan interest rate at period end (as a percent)

2.18%

Qwest Corporation | Senior notes

Long-term Debt and Credit Facilities

Total long-term debt

$ 7,229

7,311

Qwest Corporation | Medium-term notes

Long-term Debt and Credit Facilities

Total long-term debt

$ 100

0

Term loan interest rate at period end (as a percent)

2.18%

Qwest Capital Funding, Inc | Senior notes

Long-term Debt and Credit Facilities

Total long-term debt

$ 981

981

Embarq Corporation | Senior notes

Long-term Debt and Credit Facilities

Total long-term debt

2,669

Embarq Corporation | First mortgage bonds

Long-term Debt and Credit Facilities

Total long-term debt

232

Embarq Corporation | Other

Long-term Debt and Credit Facilities

Total long-term debt

$ 150

Interest rate, stated percentage (as a percent)

9.00%

Minimum | CenturyLink, Inc. | Senior notes

Long-term Debt and Credit Facilities

Interest rate, stated percentage (as a percent)

5.15%

Minimum | CenturyLink, Inc. | Credit facility

Long-term Debt and Credit Facilities

Credit facility interest rate at period end (as a percent)

2.01%

Minimum | Qwest Corporation | Senior notes

Long-term Debt and Credit Facilities

Interest rate, stated percentage (as a percent)

6.125%

Minimum | Qwest Capital Funding, Inc | Senior notes

Long-term Debt and Credit Facilities

Interest rate, stated percentage (as a percent)

6.50%

Minimum | Embarq Corporation | Senior notes

Long-term Debt and Credit Facilities

Interest rate, stated percentage (as a percent)

7.082%

Minimum | Embarq Corporation | First mortgage bonds

Long-term Debt and Credit Facilities

Interest rate, stated percentage (as a percent)

7.125%

Maximum | CenturyLink, Inc. | Senior notes

Long-term Debt and Credit Facilities

Interest rate, stated percentage (as a percent)

7.65%

Maximum | CenturyLink, Inc. | Credit facility

Long-term Debt and Credit Facilities

Credit facility interest rate at period end (as a percent)

4.25%

Maximum | Qwest Corporation | Senior notes

Long-term Debt and Credit Facilities

Interest rate, stated percentage (as a percent)

8.375%

Maximum | Qwest Capital Funding, Inc | Senior notes

Long-term Debt and Credit Facilities

Interest rate, stated percentage (as a percent)

7.75%

Maximum | Embarq Corporation | Senior notes

Long-term Debt and Credit Facilities

Interest rate, stated percentage (as a percent)

7.995%

Maximum | Embarq Corporation | First mortgage bonds

Long-term Debt and Credit Facilities

Interest rate, stated percentage (as a percent)

8.77%

[1]	Actual principal paid in all years may differ due to the possible future refinancing of outstanding debt or the issuance of new debt.

Long-Term Debt and Credit Facilities (Details 2)
$ in Millions

1 Months Ended

12 Months Ended

Jan. 31, 2016

USD ($)

Sep. 21, 2015

USD ($)

Mar. 19, 2015

USD ($)

Feb. 20, 2015

USD ($)

Dec. 03, 2014

USD ($)

lender

Sep. 29, 2014

USD ($)

Jan. 31, 2015

USD ($)

Dec. 31, 2015

USD ($)

Dec. 31, 2014

USD ($)

Dec. 31, 2013

USD ($)

Oct. 13, 2015

USD ($)

Sep. 30, 2015

USD ($)

Jun. 15, 2015

USD ($)

Feb. 15, 2015

USD ($)

Oct. 01, 2014

USD ($)

Apr. 01, 2014

USD ($)

Apr. 30, 2011

USD ($)

Long-term Debt and Credit Facilities

Total long-term debt

^[1]

$ 20,529.0

Interest expense:

Gross interest expense

1,364.0

$ 1,358.0

$ 1,339.0

Capitalized interest

(52.0)

(47.0)

(41.0)

Total interest expense

1,312.0

1,311.0

1,298.0

Repayments of long-term debt

$ 966.0

800.0

$ 2,010.0

Qwest Corporation | Revolving credit facility

Interest expense:

Debt to EBITDA ratio to be maintained under the Credit Facility

2.85

CenturyLink, Inc. | Revolving credit facility

Interest expense:

Debt to EBITDA ratio to be maintained under the Credit Facility

4.0

Senior notes | Qwest Corporation

Long-term Debt and Credit Facilities

Total long-term debt

$ 7,229.0

7,311.0

Senior notes | Qwest Corporation | Minimum

Long-term Debt and Credit Facilities

Interest rate, stated percentage (as a percent)

6.125%

Senior notes | Qwest Corporation | Maximum

Long-term Debt and Credit Facilities

Interest rate, stated percentage (as a percent)

8.375%

Senior notes | Qwest Corporation | 6.625% Notes due 2055

Long-term Debt and Credit Facilities

Aggregate principal amount of debt issuance

$ 400.0

$ 10.0

Interest rate, stated percentage (as a percent)

6.625%

Net proceeds from issuance of debt

$ 386.0

Senior notes | Qwest Corporation | 6.875% Notes due 2054

Long-term Debt and Credit Facilities

Aggregate principal amount of debt issuance

$ 500.0

Interest rate, stated percentage (as a percent)

6.875%

Net proceeds from issuance of debt

$ 483.0

Senior notes | Qwest Corporation | 7.200% Note due 2026

Long-term Debt and Credit Facilities

Interest rate, stated percentage (as a percent)

7.20%

Repurchased face amount of Senior notes

$ 250.0

Senior notes | Qwest Corporation | 6.875% Noted due 2033

Long-term Debt and Credit Facilities

Interest rate, stated percentage (as a percent)

6.875%

Repurchased face amount of Senior notes

$ 150.0

Senior notes | Qwest Corporation | 7.625 % Notes Due 2015

Long-term Debt and Credit Facilities

Interest rate, stated percentage (as a percent)

7.625%

Repurchased face amount of Senior notes

$ 92.0

Senior notes | Qwest Corporation | 7.500% Notes due 2014

Long-term Debt and Credit Facilities

Interest rate, stated percentage (as a percent)

7.50%

Repurchased face amount of Senior notes

$ 600.0

Senior notes | CenturyLink, Inc.

Long-term Debt and Credit Facilities

Total long-term debt

$ 7,975.0

7,825.0

Senior notes | CenturyLink, Inc. | Minimum

Long-term Debt and Credit Facilities

Interest rate, stated percentage (as a percent)

5.15%

Senior notes | CenturyLink, Inc. | Maximum

Long-term Debt and Credit Facilities

Interest rate, stated percentage (as a percent)

7.65%

Senior notes | CenturyLink, Inc. | 5.625% Notes due 2025

Long-term Debt and Credit Facilities

Aggregate principal amount of debt issuance

$ 500.0

Interest rate, stated percentage (as a percent)

5.625%

Net proceeds from issuance of debt

$ 494.0

Senior notes | CenturyLink, Inc. | Series M 5.00% Notes

Long-term Debt and Credit Facilities

Interest rate, stated percentage (as a percent)

5.00%

Repurchased face amount of Senior notes

$ 350.0

Senior notes | Embarq Corporation

Long-term Debt and Credit Facilities

Total long-term debt

$ 2,669.0

2,669.0

Interest expense:

Percentage of net tangible assets allowed to secure senior notes (percent)

15.00%

Senior notes | Embarq Corporation | Minimum

Long-term Debt and Credit Facilities

Interest rate, stated percentage (as a percent)

7.082%

Senior notes | Embarq Corporation | Maximum

Long-term Debt and Credit Facilities

Interest rate, stated percentage (as a percent)

7.995%

Medium-term notes | Qwest Corporation

Long-term Debt and Credit Facilities

Total long-term debt

$ 100.0

0.0

Medium-term notes | Qwest Corporation | Term loan

Long-term Debt and Credit Facilities

Aggregate principal amount of debt issuance

$ 100.0

Total long-term debt

100.0

Medium-term notes | Qwest Corporation | Term loan | Minimum | Base Rate

Long-term Debt and Credit Facilities

Interest rate margin (as a percent)

0.50%

Medium-term notes | Qwest Corporation | Term loan | Minimum | London Interbank Offered Rate (LIBOR)

Long-term Debt and Credit Facilities

Interest rate margin (as a percent)

1.50%

Medium-term notes | Qwest Corporation | Term loan | Maximum | Base Rate

Long-term Debt and Credit Facilities

Interest rate margin (as a percent)

1.50%

Medium-term notes | Qwest Corporation | Term loan | Maximum | London Interbank Offered Rate (LIBOR)

Long-term Debt and Credit Facilities

Interest rate margin (as a percent)

2.50%

Medium-term notes | CenturyLink, Inc.

Long-term Debt and Credit Facilities

Total long-term debt

358.0

380.0

Line of credit | CenturyLink, Inc.

Long-term Debt and Credit Facilities

Total long-term debt

410.0

725.0

Line of credit | CenturyLink, Inc. | Credit Facility | Revolving credit facility

Long-term Debt and Credit Facilities

Number of subsidiary Guarantors for Credit Facility

9

Maximum borrowing capacity

$ 2,000.0

Number of lenders of Credit Facility | lender

16

Line of credit | CenturyLink, Inc. | Credit Facility | Revolving credit facility | Minimum

Long-term Debt and Credit Facilities

Lender commitment

$ 3.5

Long-term Debt and Credit Facilities

Interest rate margin (as a percent)

0.00%

Long-term Debt and Credit Facilities

Interest rate margin (as a percent)

1.00%

Line of credit | CenturyLink, Inc. | Credit Facility | Revolving credit facility | Maximum

Long-term Debt and Credit Facilities

Lender commitment

$ 198.5

Long-term Debt and Credit Facilities

Interest rate margin (as a percent)

1.25%

Long-term Debt and Credit Facilities

Interest rate margin (as a percent)

2.25%

Line of credit | CenturyLink, Inc. | Credit Facility | Letter of credit

Long-term Debt and Credit Facilities

Maximum borrowing capacity

$ 400.0

Line of credit | CenturyLink, Inc. | Uncommitted revolving line of credit | Line of credit

Long-term Debt and Credit Facilities

Total long-term debt

80.0

Maximum borrowing capacity

$ 100.0

Number of lenders of revolving line of credit

1

Long-term Debt and Credit Facilities

Interest rate margin (as a percent)

1.00%

Long-term Debt and Credit Facilities

Interest rate margin (as a percent)

2.25%

First mortgage bonds | Embarq Corporation

Long-term Debt and Credit Facilities

Total long-term debt

$ 232.0

232.0

Interest expense:

Percentage of subsidiary property, plant and equipment securing debt, (percent)

10.00%

First mortgage bonds | Embarq Corporation | Minimum

Long-term Debt and Credit Facilities

Interest rate, stated percentage (as a percent)

7.125%

First mortgage bonds | Embarq Corporation | Maximum

Long-term Debt and Credit Facilities

Interest rate, stated percentage (as a percent)

8.77%

First mortgage bonds | Embarq Corporation | 7.460% Notes Due 2014

Long-term Debt and Credit Facilities

Interest rate, stated percentage (as a percent)

7.46%

Repurchased face amount of Senior notes

$ 30.0

Other | Embarq Corporation

Long-term Debt and Credit Facilities

Interest rate, stated percentage (as a percent)

9.00%

Total long-term debt

$ 150.0

150.0

Letter of credit | CenturyLink, Inc. | Uncommitted revolving letter of credit facility | Letter of credit

Long-term Debt and Credit Facilities

Maximum borrowing capacity

$ 160.0

Letters of credit outstanding

$ 109.0

$ 124.0

Subsequent Event | Senior notes | Qwest Corporation | 7.00% Notes due 2056

Long-term Debt and Credit Facilities

Aggregate principal amount of debt issuance

$ 235.0

Interest rate, stated percentage (as a percent)

7.00%

Net proceeds from issuance of debt

$ 227.0

[1]	Actual principal paid in all years may differ due to the possible future refinancing of outstanding debt or the issuance of new debt.

Long-Term Debt and Credit Facilities Long-Term Debt and Credit Facilities (Details 3) - Senior notes	Jan. 31, 2016	Sep. 21, 2015	Mar. 19, 2015	Sep. 29, 2014
6.625% Notes due 2055 \| Debt Instrument, Redemption, Period One [Member] \| Qwest Corporation
Debt Instrument, Redemption [Line Items]
Debt Instrument, Redemption Price, Percentage		100.00%
5.625% Notes due 2025 \| Debt Instrument, Redemption, Period One [Member] \| CenturyLink, Inc.
Debt Instrument, Redemption [Line Items]
Debt Instrument, Redemption, Description			greater of 100% of the principal amount of the Notes or the sum of the present value of the remaining scheduled payments of principal and interest on the Notes, discounted to the redemption date in the manner described in the Notes
5.625% Notes due 2025 \| Debt Instrument, Redemption, Period Two [Member] \| CenturyLink, Inc.
Debt Instrument, Redemption [Line Items]
Debt Instrument, Redemption, Description			redeem the Notes at par
5.625% Notes due 2025 \| Debt Instrument, Redemption, Period Three [Member] \| CenturyLink, Inc.
Debt Instrument, Redemption [Line Items]
Debt Instrument, Redemption Price, Percentage			105.625%
Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemable			35.00%
5.625% Notes due 2025 \| Debt Instrument, Redemption, Period Four [Member] \| CenturyLink, Inc.
Debt Instrument, Redemption [Line Items]
Debt Instrument, Redemption Price, Percentage			101.00%
6.875% Notes due 2054 \| Debt Instrument, Redemption, Period One [Member] \| Qwest Corporation
Debt Instrument, Redemption [Line Items]
Debt Instrument, Redemption Price, Percentage				100.00%
Subsequent Event \| 7.00% Notes due 2056 \| Debt Instrument, Redemption, Period One [Member] \| Qwest Corporation
Debt Instrument, Redemption [Line Items]
Debt Instrument, Redemption Price, Percentage	100.00%

Long-Term Debt and Credit Facilities (Details 4)
$ in Millions

Dec. 31, 2015

USD ($)

^[1]

Long-term Debt, Fiscal Year Maturity [Abstract]

$ 1,503

1,501

251

1,160

1,032

15,082

$ 20,529

[1]	Actual principal paid in all years may differ due to the possible future refinancing of outstanding debt or the issuance of new debt.

Accounts Receivable (Details) - USD ($) $ in Millions	12 Months Ended
Accounts Receivable (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Other receivables	$ 18	$ 22
Total accounts receivable	2,095	2,150
Less: allowance for doubtful accounts	(152)	(162)
Accounts receivable, less allowance	1,943	1,988
Allowance for Doubtful Accounts Receivable [Roll Forward]
Beginning balance	162	155	$ 158
Additions	177	159	152
Deductions	(187)	(152)	(155)
Ending balance	152	162	$ 155
Earned and unbilled receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total accounts receivable	288	307
Trade and purchased receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total accounts receivable	$ 1,789	$ 1,821

Property, Plant and Equipment (Details) - USD ($)
$ in Millions

12 Months Ended

Dec. 31, 2015

Dec. 31, 2014

Dec. 31, 2013

Property, plant and equipment

Gross property, plant and equipment

$ 38,785

$ 36,718

Accumulated depreciation

(20,716)

(18,285)

Net property, plant and equipment

18,069

18,433

Depreciation, Depletion and Amortization [Abstract]

Depreciation expense

2,836

2,958

$ 2,952

Land

Property, plant and equipment

Gross property, plant and equipment

571

575

Fiber, conduit and other outside plant

Property, plant and equipment

Gross property, plant and equipment

^[1]

$ 16,166

15,151

Fiber, conduit and other outside plant | Minimum

Depreciation, Depletion and Amortization [Abstract]

Depreciable Lives

15 years

Fiber, conduit and other outside plant | Maximum

Depreciation, Depletion and Amortization [Abstract]

Depreciable Lives

45 years

Central office and other network electronics

Property, plant and equipment

Gross property, plant and equipment

^[2]

$ 14,144

13,248

Central office and other network electronics | Minimum

Depreciation, Depletion and Amortization [Abstract]

Depreciable Lives

3 years

Central office and other network electronics | Maximum

Depreciation, Depletion and Amortization [Abstract]

Depreciable Lives

10 years

Support assets

Property, plant and equipment

Gross property, plant and equipment

^[3]

$ 7,000

6,578

Support assets | Minimum

Depreciation, Depletion and Amortization [Abstract]

Depreciable Lives

3 years

Support assets | Maximum

Depreciation, Depletion and Amortization [Abstract]

Depreciable Lives

30 years

Construction in progress

Property, plant and equipment

Gross property, plant and equipment

^[4]

$ 904

1,166

Qwest Corporation | Office building

Depreciation, Depletion and Amortization [Abstract]

Impairment of office building

17

CenturyLink, Inc. | Office building

Depreciation, Depletion and Amortization [Abstract]

Proceeds from sale of office building

$ 12

[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, data centers, 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.

Property, Plant and Equipment (Details 2) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Asset Retirement Obligation
Balance at beginning of year	$ 107	$ 106	$ 106
Accretion expense	7	7	7
Liabilities incurred	0	6	0
Liabilities settled	(2)	(2)	(4)
Change in estimate	(21)	(10)	(3)
Balance at end of year	$ 91	$ 107	$ 106

Severance and Leased Real Estate (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Severance
Restructuring reserve
Balance at the beginning of the period	$ 26	$ 17
Accrued to expense	96	87
Payments, net	(108)	(78)
Reversals and adjustments	0	0
Balance at the end of the period	14	26
Qwest Communications International Inc \| Leased real estate
Severance and Leased Real Estate
Current portion of leased real estate accrual	9
Noncurrent portion of leased real estate accrual	$ 71
Weighted average lease terms (in years)	8 years
Restructuring reserve
Balance at the beginning of the period	$ 96	113
Accrued to expense	0	1
Payments, net	(13)	(16)
Reversals and adjustments	3	(2)
Balance at the end of the period	$ 80	$ 96
Qwest Communications International Inc \| Leased real estate \| Minimum
Severance and Leased Real Estate
Remaining lease terms	4 months
Qwest Communications International Inc \| Leased real estate \| Maximum
Severance and Leased Real Estate
Remaining lease terms	10 years

Employee Benefits (Details) - USD ($)
$ in Millions

3 Months Ended

12 Months Ended

Jan. 02, 2016

Dec. 08, 2014

Dec. 31, 2015

Dec. 31, 2014

Dec. 31, 2015

Dec. 31, 2014

Dec. 31, 2013

Dec. 31, 2015

Dec. 31, 2014

Dec. 31, 2013

Employee Benefits

Benefit obligation

$ 16,916

$ 18,872

$ 17,089

$ 16,916

$ 18,872

$ 17,089

Defined Benefit Plan, assumed health care cost trend rates

Ultimate health care cost trend rate (as a percent)

4.50%

Year that health care cost rate reaches ultimate trend rate

2025

2024

2022

Effect of change of 100 basis points in the assumed initial health care cost trend rate

Effect on the aggregate of the service and interest cost components of net periodic post-retirement benefit expense (statements of operations) - Increase

$ 3

Effect on the aggregate of the service and interest cost components of net periodic post-retirement benefit expense (statements of operations) - Decrease

(3)

Effect of one-percentage point increase on postretirement benefit obligation

73

Effect of one-percentage point decrease on postretirement benefit obligation

$ (68)

Actuarial assumptions at beginning of year:

Ultimate health care cost trend rate (as a percent)

4.50%

Year that health care cost rate reaches ultimate trend rate

2025

2024

2022

Components of net periodic benefit (income) expense

Expected return on plan assets

$ (919)

(924)

Settlements

(63)

Actuarial assumptions at end of year:

Ultimate health care cost trend rate (as a percent)

4.50%

Year that health care cost rate reaches ultimate trend rate

2025

2024

2022

Change in benefit obligation

Benefit obligation at beginning of year

16,916

$ 18,872

17,089

Benefit obligation at end of year

16,916

18,872

$ 16,916

18,872

17,089

Projected benefit obligation increase due to adoption of new mortality table

$ (379)

$ 1,300

Remaining estimated life of plan participants

8 years

Change in plan assets

Return on plan assets

$ (158)

1,410

Settlements

$ 0

460

0

Pension Plan

Employee Benefits

Amortization period of the plan shortfall

7 years

Unfunded status

2,277

2,471

Employer contributions

$ 100

157

146

Benefits paid by company

6

5

Benefits paid from plan assets

356

1,438

^[1]

845

^[1]

931

^[1]

Lump sum pension settlements

$ 460

0

460

0

Termination pension settlement threshold

$ 418

Pension settlement charge

63

Fair value of plan assets

11,072

12,571

12,346

12,321

11,072

12,571

$ 12,346

Benefit obligation

13,349

15,042

$ 15,042

$ 13,401

$ 14,881

13,349

$ 15,042

13,401

Estimated future benefit payments:

1,059

1,010

991

973

954

$ 4,433

Actuarial assumptions at beginning of year:

Rate of compensation increase (as a percent)

3.25%

Expected long-term rate of return on plan assets (as a percent)

7.50%

Components of net periodic benefit (income) expense

Service cost

$ 83

$ 77

$ 91

Interest cost

568

602

544

Expected return on plan assets

(898)

(891)

(896)

Settlements

0

63

0

Recognition of prior service cost

5

Recognition of actuarial loss

161

22

84

Net periodic pension benefit income

(81)

(122)

(172)

Actuarial assumptions at end of year:

Rate of compensation increase (as a percent)

3.25%

Change in benefit obligation

Benefit obligation at beginning of year

13,349

15,042

13,401

14,881

Service cost

83

77

91

Interest cost

568

602

544

Plan amendments

(100)

4

0

Actuarial loss (gain)

(800)

2,269

(1,179)

Benefits paid by company

6

5

Benefits paid from plan assets

356

1,438

^[1]

845

^[1]

931

^[1]

Benefit obligation at end of year

13,349

15,042

13,349

15,042

13,401

Change in plan assets

Fair value of plan assets at beginning of year

11,072

12,571

12,346

12,321

Return on plan assets

(161)

1,373

810

Employer contributions

100

157

146

Benefits paid from plan assets

356

1,438

^[1]

845

^[1]

931

^[1]

Fair value of plan assets at end of year

11,072

12,571

$ 11,072

$ 12,571

$ 12,346

Target allocation of plan assets

Expected long-term rate of return on plan assets (as a percent)

7.50%

Pension Plan | Interest rate sensitive investments

Target allocation of plan assets

Target asset allocation percentage (as a percent)

45.00%

Pension Plan | Investment grade bonds

Target allocation of plan assets

Target asset allocation percentage (as a percent)

30.00%

Pension Plan | High yield and emerging market bonds

Target allocation of plan assets

Target asset allocation percentage (as a percent)

10.00%

Pension Plan | Diversified strategies

Target allocation of plan assets

Target asset allocation percentage (as a percent)

5.00%

Pension Plan | Interest rate investments with higher returns

Target allocation of plan assets

Target asset allocation percentage (as a percent)

55.00%

Pension Plan | U.S. stocks

Employee Benefits

Fair value of plan assets

^[2]

1,201

1,390

$ 1,390

$ 1,201

$ 1,390

Change in plan assets

Fair value of plan assets at beginning of year

^[2]

1,201

1,390

Fair value of plan assets at end of year

^[2]

1,201

1,390

$ 1,201

1,390

Target allocation of plan assets

Target asset allocation percentage (as a percent)

15.00%

Pension Plan | Developed market Non-U.S. stocks

Employee Benefits

Fair value of plan assets

^[1]

1,128

1,170

$ 1,170

1,170

$ 1,128

$ 1,170

Change in plan assets

Fair value of plan assets at beginning of year

^[1]

1,128

1,170

Fair value of plan assets at end of year

^[1]

1,128

1,170

$ 1,128

$ 1,170

Target allocation of plan assets

Target asset allocation percentage (as a percent)

15.00%

Pension Plan | Diversified multi-asset classes

Target allocation of plan assets

Target asset allocation percentage (as a percent)

7.00%

Pension Plan | Other

Target allocation of plan assets

Target asset allocation percentage (as a percent)

10.00%

Pension Plan | Real estate

Target allocation of plan assets

Target asset allocation percentage (as a percent)

8.00%

Pension Plan | Minimum

Actuarial assumptions at beginning of year:

Discount rate (as a percent)

3.50%

4.20%

3.50%

Actuarial assumptions at end of year:

Discount rate (as a percent)

3.50%

4.20%

Pension Plan | Maximum

Actuarial assumptions at beginning of year:

Discount rate (as a percent)

4.10%

5.10%

4.20%

Actuarial assumptions at end of year:

Discount rate (as a percent)

4.10%

5.10%

Qualified Pension Plan

Employee Benefits

Unfunded status

$ 2,215

$ 2,403

Employer contributions

$ 100

Change in plan assets

Employer contributions

100

Non-qualified Pension Plan

Employee Benefits

Benefits paid by company

6

Estimated future benefit payments:

2016

5

Change in benefit obligation

Benefits paid by company

6

Post-Retirement Benefit Plans

Employee Benefits

Unfunded status

3,374

3,477

Employer contributions

0

Benefits paid by company

181

$ 166

$ 266

Benefits paid from plan assets

163

219

136

Fair value of plan assets

193

353

535

626

193

353

535

Benefits paid, net of participant contributions and direct subsidy receipts

116

Benefit obligation

3,567

3,830

$ 3,830

$ 3,688

$ 4,075

$ 3,567

$ 3,830

$ 3,688

Defined Benefit Plan, assumed health care cost trend rates

Decrease in health care cost trend rate per year

decrease between 0.05% to 0.10% per year

Health care cost trend rate (as a percent)

5.00%

Ultimate health care cost trend rate (as a percent)

4.50%

Year that health care cost rate reaches ultimate trend rate

2025

2024

Estimated future benefit payments:

$ 309

300

290

283

276

1,256

Medicare Part D Subsidy Receipts

(7)

(7)

(7)

(7)

(7)

$ (30)

Actuarial assumptions at beginning of year:

Discount rate (as a percent)

3.80%

4.50%

Expected long-term rate of return on plan assets (as a percent)

7.50%

Ultimate health care cost trend rate (as a percent)

4.50%

Year that health care cost rate reaches ultimate trend rate

2025

2024

Components of net periodic benefit (income) expense

Service cost

$ 24

$ 22

$ 24

Interest cost

140

159

140

Expected return on plan assets

(21)

(33)

(39)

Recognition of prior service cost

19

20

0

Recognition of actuarial loss

0

4

Net periodic pension benefit income

$ 162

$ 168

$ 129

Actuarial assumptions at end of year:

Discount rate (as a percent)

4.15%

3.80%

Initial health care cost trend rate (as a percent)

6.50%

Ultimate health care cost trend rate (as a percent)

4.50%

Year that health care cost rate reaches ultimate trend rate

2025

2024

Change in benefit obligation

Benefit obligation at beginning of year

3,567

$ 3,830

$ 3,688

$ 4,075

Service cost

24

22

24

Interest cost

140

159

140

Participant contributions

57

69

96

Plan amendments

0

23

141

Direct subsidy receipts

8

9

13

Actuarial loss (gain)

(148)

245

(399)

Benefits paid by company

181

166

266

Benefits paid from plan assets

163

219

136

Benefit obligation at end of year

3,567

3,830

3,567

3,830

3,688

Change in plan assets

Fair value of plan assets at beginning of year

193

353

535

626

Return on plan assets

3

37

45

Employer contributions

0

Benefits paid from plan assets

163

219

136

Fair value of plan assets at end of year

193

353

$ 193

353

$ 535

Target allocation of plan assets

Expected long-term rate of return on plan assets (as a percent)

7.50%

Post-Retirement Benefit Plans | U.S. stocks

Employee Benefits

Fair value of plan assets

16

^[2]

16

^[2]

35

$ 35

35

$ 16

^[2]

$ 35

Change in plan assets

Fair value of plan assets at beginning of year

16

^[2]

35

Fair value of plan assets at end of year

16

^[2]

35

16

^[2]

35

Post-Retirement Benefit Plans | Developed market Non-U.S. stocks

Employee Benefits

Fair value of plan assets

12

^[1]

12

^[1]

33

$ 12

^[1]

$ 33

Change in plan assets

Fair value of plan assets at beginning of year

$ 12

^[1]

33

Fair value of plan assets at end of year

$ 12

^[1]

$ 33

$ 12

^[1]

$ 33

Post-Retirement Benefit Plans | Equity Securities

Target allocation of plan assets

Target asset allocation percentage (as a percent)

20.00%

Post-Retirement Benefit Plans | Non-equity investments

Target allocation of plan assets

Target asset allocation percentage (as a percent)

80.00%

Post-Retirement Benefit Plans | Minimum

Actuarial assumptions at beginning of year:

Discount rate (as a percent)

3.60%

Expected long-term rate of return on plan assets (as a percent)

6.00%

Actuarial assumptions at end of year:

Initial health care cost trend rate (as a percent)

5.00%

6.00%

Target allocation of plan assets

Expected long-term rate of return on plan assets (as a percent)

6.00%

Post-Retirement Benefit Plans | Maximum

Actuarial assumptions at beginning of year:

Discount rate (as a percent)

Expected long-term rate of return on plan assets (as a percent)

7.50%

7.30%

Actuarial assumptions at end of year:

Initial health care cost trend rate (as a percent)

5.25%

6.50%

Target allocation of plan assets

Expected long-term rate of return on plan assets (as a percent)

7.50%

7.30%

Scenario, Forecast [Member] | Pension Plan

Actuarial assumptions at beginning of year:

Expected long-term rate of return on plan assets (as a percent)

7.50%

Target allocation of plan assets

Expected long-term rate of return on plan assets (as a percent)

7.50%

Expected long-term return on assets, net of administrative expenses

7.00%

Scenario, Forecast [Member] | Post-Retirement Benefit Plans

Employee Benefits

Benefits paid, net of participant contributions and direct subsidy receipts

$ 137

Actuarial assumptions at beginning of year:

Expected long-term rate of return on plan assets (as a percent)

7.00%

Target allocation of plan assets

Expected long-term rate of return on plan assets (as a percent)

7.00%

[1]

Non-U.S. stocks represent investments in stocks of companies based in developed countries outside the U.S. as well as commingled funds. The valuation inputs for non-U.S. stocks are based on the last published price reported on the major stock market on which the securities are traded and are primarily classified as Level 1. The commingled funds are valued at NAV based on the market value of the underlying investments using the same valuation inputs described above.

[2]

U.S. stocks represent investments in stocks of U.S. based companies as well as commingled U.S. stock funds. The valuation inputs for U.S. stocks are based on the last published price reported on the major stock market on which the securities are traded and are classified as Level 1. The commingled funds are valued at NAV based on the market value of the underlying investments using the same valuation inputs described above.

Employee Benefits (Details 2) - USD ($)
$ in Millions

12 Months Ended

Dec. 31, 2015

Dec. 31, 2014

Dec. 31, 2013

Dec. 31, 2015

Dec. 31, 2014

Dec. 31, 2013

Dec. 31, 2012

Actual return on plan assets:

Actual gains (losses) on pension and post retirement plan assets

$ (158)

$ 1,410

Expected return

919

924

Difference between the actual and expected returns on pension and post-retirement plan assets

1,077

486

Unfunded Status

Benefit obligation

$ (16,916)

$ (18,872)

$ (17,089)

Non-current portion of unfunded status

(5,511)

(5,808)

Accumulated other comprehensive (loss) income

Total

(1,895)

(1,992)

Recognition of Net Periodic Benefits Expense

Net periodic (income) expense

115

Deferrals

Total

(18)

Net Change in AOCI

Total

97

Health Care and Life Insurance

Active health care benefit expenses

381

$ 362

Participating employees' contribution to health care plan

125

136

117

Pension Plan

Employee Benefits

Fair value of plan assets valued at NAV

5,293

5,749

Total investments, excluding investments valued at NAV

5,779

6,822

Fair value of plan assets

12,571

12,346

12,321

11,072

12,571

12,346

$ 12,321

Change in plan assets

Fair value of plan assets at beginning of year

12,571

12,346

12,321

Actual return on plan assets:

Fair value of plan assets at end of year

11,072

12,571

12,346

Actual gains (losses) on pension and post retirement plan assets

(161)

1,373

810

Expected return

898

891

896

Unfunded Status

Benefit obligation

(13,349)

(15,042)

(13,401)

(14,881)

Fair value of plan assets

12,571

12,346

12,321

11,072

12,571

12,346

12,321

Unfunded status

(2,277)

(2,471)

Current portion of unfunded status

(5)

(6)

Non-current portion of unfunded status

(2,272)

(2,465)

Accumulated other comprehensive (loss) income

Net actuarial (loss) gain

(2,857)

(2,760)

Prior service (cost) benefit

72

(32)

Deferred income tax benefit (expense)

1,070

1,072

Total

(1,715)

(1,720)

Recognition of Net Periodic Benefits Expense

Net actuarial (loss) gain

161

22

84

Recognition of prior service cost

5

Deferred income tax benefit (expense)

(63)

Net periodic (income) expense

103

Deferrals

Net actuarial (loss) gain

(258)

Prior service (cost) benefit

99

Deferred income tax benefit (expense)

61

Total

(98)

Net Change in AOCI

Net actuarial (loss) gain

(97)

Prior service (cost) benefit

104

Deferred income tax benefit (expense)

(2)

Total

5

Estimated recognition of net periodic benefit expense in 2016:

Net actuarial loss

(168)

Prior service (cost)/income

8

Deferred income tax benefit

61

Estimated ner periodic benefit expense to be recorded in 2016 as a component of other comprehensive income (loss)

(99)

Pension Plan | Level 1

Employee Benefits

Total investments, excluding investments valued at NAV

3,755

3,836

Pension Plan | Level 2

Employee Benefits

Total investments, excluding investments valued at NAV

2,010

2,979

Pension Plan | Level 3

Employee Benefits

Total investments, excluding investments valued at NAV

14

7

Fair value of plan assets

7

0

14

7

0

Change in plan assets

Fair value of plan assets at beginning of year

7

0

Net transfers

5

6

Acquisitions

4

1

Dispositions

(2)

(3)

Actual return on plan assets:

Gains relating to assets sold during the year

0

4

(Losses) gains relating to assets still held at year-end

0

(1)

Fair value of plan assets at end of year

14

7

0

Unfunded Status

Fair value of plan assets

7

0

14

7

0

Pension Plan | Exchange-traded U.S. equity futures

Employee Benefits

Gross notional exposure

79

134

Pension Plan | Exchange-traded Treasury and other interest rate futures

Employee Benefits

Gross notional exposure

1,767

2,451

Pension Plan | Interest rate swaps

Employee Benefits

Gross notional exposure

550

579

Pension Plan | Credit default swaps

Employee Benefits

Gross notional exposure

189

382

Pension Plan | Foreign exchange forwards

Employee Benefits

Gross notional exposure

992

1,195

Pension Plan | Options

Employee Benefits

Gross notional exposure

285

529

Pension Plan | Investment grade bonds

Employee Benefits

Fair value of plan assets valued at NAV

115

148

Fair value of plan assets

^[1]

2,346

1,886

2,346

Change in plan assets

Fair value of plan assets at beginning of year

^[1]

2,346

Actual return on plan assets:

Fair value of plan assets at end of year

^[1]

1,886

2,346

Unfunded Status

Fair value of plan assets

^[1]

2,346

1,886

2,346

Pension Plan | Investment grade bonds | Level 1

Employee Benefits

Fair value of plan assets

^[1]

1,068

841

1,068

Change in plan assets

Fair value of plan assets at beginning of year

^[1]

1,068

Actual return on plan assets:

Fair value of plan assets at end of year

^[1]

841

1,068

Unfunded Status

Fair value of plan assets

^[1]

1,068

841

1,068

Pension Plan | Investment grade bonds | Level 2

Employee Benefits

Fair value of plan assets

^[1]

1,278

1,045

1,278

Change in plan assets

Fair value of plan assets at beginning of year

^[1]

1,278

Actual return on plan assets:

Fair value of plan assets at end of year

^[1]

1,045

1,278

Unfunded Status

Fair value of plan assets

^[1]

1,278

1,045

1,278

Pension Plan | Investment grade bonds | Level 3

Employee Benefits

Fair value of plan assets

^[1]

0

Change in plan assets

Fair value of plan assets at beginning of year

^[1]

0

Actual return on plan assets:

Fair value of plan assets at end of year

^[1]

0

Unfunded Status

Fair value of plan assets

^[1]

0

Pension Plan | High yield bonds

Employee Benefits

Fair value of plan assets valued at NAV

512

860

Fair value of plan assets

^[2]

654

557

654

Change in plan assets

Fair value of plan assets at beginning of year

^[2]

654

Actual return on plan assets:

Fair value of plan assets at end of year

^[2]

557

654

Unfunded Status

Fair value of plan assets

^[2]

654

557

654

Pension Plan | High yield bonds | Level 1

Employee Benefits

Fair value of plan assets

^[2]

0

Change in plan assets

Fair value of plan assets at beginning of year

^[2]

0

Actual return on plan assets:

Fair value of plan assets at end of year

^[2]

0

Unfunded Status

Fair value of plan assets

^[2]

0

Pension Plan | High yield bonds | Level 2

Employee Benefits

Fair value of plan assets

^[2]

647

544

647

Change in plan assets

Fair value of plan assets at beginning of year

^[2]

647

Actual return on plan assets:

Fair value of plan assets at end of year

^[2]

544

647

Unfunded Status

Fair value of plan assets

^[2]

647

544

647

Pension Plan | High yield bonds | Level 3

Employee Benefits

Fair value of plan assets

7

^[2]

0

13

^[2]

7

^[2]

0

Change in plan assets

Fair value of plan assets at beginning of year

7

^[2]

0

Net transfers

4

6

Acquisitions

4

1

Dispositions

(2)

(3)

Actual return on plan assets:

Gains relating to assets sold during the year

0

4

(Losses) gains relating to assets still held at year-end

0

(1)

Fair value of plan assets at end of year

13

^[2]

7

^[2]

0

Unfunded Status

Fair value of plan assets

7

^[2]

0

13

^[2]

7

^[2]

0

Pension Plan | Emerging market bonds

Employee Benefits

Fair value of plan assets valued at NAV

9

27

Fair value of plan assets

^[3]

615

441

615

Change in plan assets

Fair value of plan assets at beginning of year

^[3]

615

Actual return on plan assets:

Fair value of plan assets at end of year

^[3]

441

615

Unfunded Status

Fair value of plan assets

^[3]

615

441

615

Pension Plan | Emerging market bonds | Level 1

Employee Benefits

Fair value of plan assets

^[3]

208

Change in plan assets

Fair value of plan assets at beginning of year

^[3]

208

Actual return on plan assets:

Fair value of plan assets at end of year

^[3]

208

Unfunded Status

Fair value of plan assets

^[3]

208

Pension Plan | Emerging market bonds | Level 2

Employee Benefits

Fair value of plan assets

^[3]

407

232

407

Change in plan assets

Fair value of plan assets at beginning of year

^[3]

407

Actual return on plan assets:

Fair value of plan assets at end of year

^[3]

232

407

Unfunded Status

Fair value of plan assets

^[3]

407

232

407

Pension Plan | Emerging market bonds | Level 3

Employee Benefits

Fair value of plan assets

0

^[3]

0

1

^[3]

0

^[3]

0

Change in plan assets

Fair value of plan assets at beginning of year

0

^[3]

0

Net transfers

1

0

Acquisitions

0

Dispositions

0

Actual return on plan assets:

Gains relating to assets sold during the year

0

(Losses) gains relating to assets still held at year-end

0

Fair value of plan assets at end of year

1

^[3]

0

^[3]

0

Unfunded Status

Fair value of plan assets

0

^[3]

0

1

^[3]

0

^[3]

0

Pension Plan | Convertible bonds

Employee Benefits

Fair value of plan assets valued at NAV

0

10

Fair value of plan assets

^[4]

4

2

4

Change in plan assets

Fair value of plan assets at beginning of year

^[4]

4

Actual return on plan assets:

Fair value of plan assets at end of year

^[4]

2

4

Unfunded Status

Fair value of plan assets

^[4]

4

2

4

Pension Plan | Convertible bonds | Level 1

Employee Benefits

Fair value of plan assets

^[4]

0

Change in plan assets

Fair value of plan assets at beginning of year

^[4]

0

Actual return on plan assets:

Fair value of plan assets at end of year

^[4]

0

Unfunded Status

Fair value of plan assets

^[4]

0

Pension Plan | Convertible bonds | Level 2

Employee Benefits

Fair value of plan assets

^[4]

4

2

4

Change in plan assets

Fair value of plan assets at beginning of year

^[4]

4

Actual return on plan assets:

Fair value of plan assets at end of year

^[4]

2

4

Unfunded Status

Fair value of plan assets

^[4]

4

2

4

Pension Plan | Convertible bonds | Level 3

Employee Benefits

Fair value of plan assets

^[4]

0

Change in plan assets

Fair value of plan assets at beginning of year

^[4]

0

Actual return on plan assets:

Fair value of plan assets at end of year

^[4]

0

Unfunded Status

Fair value of plan assets

^[4]

0

Pension Plan | Diversified strategies

Employee Benefits

Fair value of plan assets valued at NAV

516

718

Pension Plan | U.S. stocks

Employee Benefits

Fair value of plan assets valued at NAV

70

86

Fair value of plan assets

^[5]

1,390

1,201

1,390

Change in plan assets

Fair value of plan assets at beginning of year

^[5]

1,390

Actual return on plan assets:

Fair value of plan assets at end of year

^[5]

1,201

1,390

Unfunded Status

Fair value of plan assets

^[5]

1,390

1,201

1,390

Pension Plan | U.S. stocks | Level 1

Employee Benefits

Fair value of plan assets

^[5]

1,389

1,201

1,389

Change in plan assets

Fair value of plan assets at beginning of year

^[5]

1,389

Actual return on plan assets:

Fair value of plan assets at end of year

^[5]

1,201

1,389

Unfunded Status

Fair value of plan assets

^[5]

1,389

1,201

1,389

Pension Plan | U.S. stocks | Level 2

Employee Benefits

Fair value of plan assets

^[5]

1

0

1

Change in plan assets

Fair value of plan assets at beginning of year

^[5]

1

Actual return on plan assets:

Fair value of plan assets at end of year

^[5]

0

1

Unfunded Status

Fair value of plan assets

^[5]

1

0

1

Pension Plan | U.S. stocks | Level 3

Employee Benefits

Fair value of plan assets

^[5]

0

Change in plan assets

Fair value of plan assets at beginning of year

^[5]

0

Actual return on plan assets:

Fair value of plan assets at end of year

^[5]

0

Unfunded Status

Fair value of plan assets

^[5]

0

Pension Plan | Non-U.S. stocks

Employee Benefits

Fair value of plan assets valued at NAV

289

384

Fair value of plan assets

^[6]

1,170

1,128

1,170

Change in plan assets

Fair value of plan assets at beginning of year

^[6]

1,170

Actual return on plan assets:

Fair value of plan assets at end of year

^[6]

1,128

1,170

Unfunded Status

Fair value of plan assets

^[6]

1,170

1,128

1,170

Pension Plan | Non-U.S. stocks | Level 1

Employee Benefits

Fair value of plan assets

^[6]

1,169

1,127

1,169

Change in plan assets

Fair value of plan assets at beginning of year

^[6]

1,169

Actual return on plan assets:

Fair value of plan assets at end of year

^[6]

1,127

1,169

Unfunded Status

Fair value of plan assets

^[6]

1,169

1,127

1,169

Pension Plan | Non-U.S. stocks | Level 2

Employee Benefits

Fair value of plan assets

^[6]

1

Change in plan assets

Fair value of plan assets at beginning of year

^[6]

1

Actual return on plan assets:

Fair value of plan assets at end of year

^[6]

1

Unfunded Status

Fair value of plan assets

^[6]

1

Pension Plan | Non-U.S. stocks | Level 3

Employee Benefits

Fair value of plan assets

^[6]

0

Change in plan assets

Fair value of plan assets at beginning of year

^[6]

0

Actual return on plan assets:

Fair value of plan assets at end of year

^[6]

0

Unfunded Status

Fair value of plan assets

^[6]

0

Pension Plan | Multi-asset strategies

Employee Benefits

Fair value of plan assets valued at NAV

386

0

Fair value of plan assets

^[7]

376

Actual return on plan assets:

Fair value of plan assets at end of year

^[7]

376

Unfunded Status

Fair value of plan assets

^[7]

376

Pension Plan | Multi-asset strategies | Level 1

Employee Benefits

Fair value of plan assets

^[6]

376

Actual return on plan assets:

Fair value of plan assets at end of year

^[6]

376

Unfunded Status

Fair value of plan assets

^[6]

376

Pension Plan | Multi-asset strategies | Level 2

Employee Benefits

Fair value of plan assets

^[6]

0

Actual return on plan assets:

Fair value of plan assets at end of year

^[6]

0

Unfunded Status

Fair value of plan assets

^[6]

0

Pension Plan | Multi-asset strategies | Level 3

Employee Benefits

Fair value of plan assets

^[6]

0

Actual return on plan assets:

Fair value of plan assets at end of year

^[6]

0

Unfunded Status

Fair value of plan assets

^[6]

0

Pension Plan | Emerging market stocks

Employee Benefits

Fair value of plan assets valued at NAV

64

102

Pension Plan | Private equity

Employee Benefits

Fair value of plan assets valued at NAV

526

673

Pension Plan | Private debt

Employee Benefits

Fair value of plan assets valued at NAV

371

394

Pension Plan | Market Neutral Hedge Funds

Employee Benefits

Fair value of plan assets valued at NAV

825

1,026

Pension Plan | Directional Hedge Funds

Employee Benefits

Fair value of plan assets valued at NAV

594

558

Pension Plan | Real Estate

Employee Benefits

Fair value of plan assets valued at NAV

968

699

Pension Plan | Derivatives

Employee Benefits

Fair value of plan assets

^[8]

17

(4)

17

Change in plan assets

Fair value of plan assets at beginning of year

^[8]

17

Actual return on plan assets:

Fair value of plan assets at end of year

^[8]

(4)

17

Unfunded Status

Fair value of plan assets

^[8]

17

(4)

17

Pension Plan | Derivatives | Level 1

Employee Benefits

Fair value of plan assets

^[8]

2

Change in plan assets

Fair value of plan assets at beginning of year

^[8]

2

Actual return on plan assets:

Fair value of plan assets at end of year

^[8]

2

Unfunded Status

Fair value of plan assets

^[8]

2

Pension Plan | Derivatives | Level 2

Employee Benefits

Fair value of plan assets

^[8]

15

(6)

15

Change in plan assets

Fair value of plan assets at beginning of year

^[8]

15

Actual return on plan assets:

Fair value of plan assets at end of year

^[8]

(6)

15

Unfunded Status

Fair value of plan assets

^[8]

15

(6)

15

Pension Plan | Derivatives | Level 3

Employee Benefits

Fair value of plan assets

^[8]

0

Change in plan assets

Fair value of plan assets at beginning of year

^[8]

0

Actual return on plan assets:

Fair value of plan assets at end of year

^[8]

0

Unfunded Status

Fair value of plan assets

^[8]

0

Pension Plan | Cash equivalents and short-term investment funds

Employee Benefits

Fair value of plan assets valued at NAV

48

64

Fair value of plan assets

^[9]

626

192

626

Change in plan assets

Fair value of plan assets at beginning of year

^[9]

626

Actual return on plan assets:

Fair value of plan assets at end of year

^[9]

192

626

Unfunded Status

Fair value of plan assets

^[9]

626

192

626

Pension Plan | Cash equivalents and short-term investment funds | Level 1

Employee Benefits

Fair value of plan assets

^[9]

0

Change in plan assets

Fair value of plan assets at beginning of year

^[9]

0

Actual return on plan assets:

Fair value of plan assets at end of year

^[9]

0

Unfunded Status

Fair value of plan assets

^[9]

0

Pension Plan | Cash equivalents and short-term investment funds | Level 2

Employee Benefits

Fair value of plan assets

^[9]

626

192

626

Change in plan assets

Fair value of plan assets at beginning of year

^[9]

626

Actual return on plan assets:

Fair value of plan assets at end of year

^[9]

192

626

Unfunded Status

Fair value of plan assets

^[9]

626

192

626

Pension Plan | Cash equivalents and short-term investment funds | Level 3

Employee Benefits

Fair value of plan assets

^[9]

0

Change in plan assets

Fair value of plan assets at beginning of year

^[9]

0

Actual return on plan assets:

Fair value of plan assets at end of year

^[9]

0

Unfunded Status

Fair value of plan assets

^[9]

0

Post-Retirement Benefit Plans

Employee Benefits

Fair value of plan assets valued at NAV

153

264

Total investments, excluding investments valued at NAV

40

89

Fair value of plan assets

353

535

626

193

353

535

626

Change in plan assets

Fair value of plan assets at beginning of year

353

535

626

Actual return on plan assets:

Fair value of plan assets at end of year

193

353

535

Actual gains (losses) on pension and post retirement plan assets

3

37

45

Expected return

21

33

39

Unfunded Status

Benefit obligation

(3,567)

(3,830)

(3,688)

(4,075)

Fair value of plan assets

353

535

626

193

353

$ 535

$ 626

Unfunded status

(3,374)

(3,477)

Current portion of unfunded status

(135)

(134)

Non-current portion of unfunded status

(3,239)

(3,343)

Accumulated other comprehensive (loss) income

Net actuarial (loss) gain

(147)

(277)

Prior service (cost) benefit

(147)

(166)

Deferred income tax benefit (expense)

114

171

Total

(180)

(272)

Recognition of Net Periodic Benefits Expense

Net actuarial (loss) gain

0

4

Recognition of prior service cost

19

20

$ 0

Deferred income tax benefit (expense)

(7)

Net periodic (income) expense

12

Deferrals

Net actuarial (loss) gain

130

Prior service (cost) benefit

0

Deferred income tax benefit (expense)

(50)

Total

80

Net Change in AOCI

Net actuarial (loss) gain

130

Prior service (cost) benefit

19

Deferred income tax benefit (expense)

(57)

Total

92

Estimated recognition of net periodic benefit expense in 2016:

Net actuarial loss

0

Prior service (cost)/income

(20)

Deferred income tax benefit

8

Estimated ner periodic benefit expense to be recorded in 2016 as a component of other comprehensive income (loss)

(12)

Post-Retirement Benefit Plans | Level 1

Employee Benefits

Total investments, excluding investments valued at NAV

34

79

Post-Retirement Benefit Plans | Level 2

Employee Benefits

Total investments, excluding investments valued at NAV

6

10

Post-Retirement Benefit Plans | Level 3

Employee Benefits

Total investments, excluding investments valued at NAV

0

Post-Retirement Benefit Plans | Exchange-traded U.S. equity futures

Employee Benefits

Gross notional exposure

0

7

Post-Retirement Benefit Plans | Exchange-traded Treasury and other interest rate futures

Employee Benefits

Gross notional exposure

0

Post-Retirement Benefit Plans | Interest rate swaps

Employee Benefits

Gross notional exposure

0

Post-Retirement Benefit Plans | Credit default swaps

Employee Benefits

Gross notional exposure

0

Post-Retirement Benefit Plans | Foreign exchange forwards

Employee Benefits

Gross notional exposure

0

13

Post-Retirement Benefit Plans | Options

Employee Benefits

Gross notional exposure

0

Post-Retirement Benefit Plans | Investment grade bonds

Employee Benefits

Fair value of plan assets valued at NAV

35

71

Fair value of plan assets

6

3

^[1]

6

Change in plan assets

Fair value of plan assets at beginning of year

6

Actual return on plan assets:

Fair value of plan assets at end of year

3

^[1]

6

Unfunded Status

Fair value of plan assets

6

3

^[1]

6

Post-Retirement Benefit Plans | Investment grade bonds | Level 1

Employee Benefits

Fair value of plan assets

5

2

^[1]

5

Change in plan assets

Fair value of plan assets at beginning of year

5

Actual return on plan assets:

Fair value of plan assets at end of year

2

^[1]

5

Unfunded Status

Fair value of plan assets

5

2

^[1]

5

Post-Retirement Benefit Plans | Investment grade bonds | Level 2

Employee Benefits

Fair value of plan assets

1

^[1]

1

Change in plan assets

Fair value of plan assets at beginning of year

1

Actual return on plan assets:

Fair value of plan assets at end of year

1

^[1]

1

Unfunded Status

Fair value of plan assets

1

^[1]

1

Post-Retirement Benefit Plans | Investment grade bonds | Level 3

Employee Benefits

Fair value of plan assets

0

^[1]

0

Change in plan assets

Fair value of plan assets at beginning of year

0

Actual return on plan assets:

Fair value of plan assets at end of year

0

^[1]

0

Unfunded Status

Fair value of plan assets

0

^[1]

0

Post-Retirement Benefit Plans | High yield bonds

Employee Benefits

Fair value of plan assets valued at NAV

1

14

Fair value of plan assets

1

^[2]

1

Change in plan assets

Fair value of plan assets at beginning of year

1

Actual return on plan assets:

Fair value of plan assets at end of year

1

^[2]

1

Unfunded Status

Fair value of plan assets

1

^[2]

1

Post-Retirement Benefit Plans | High yield bonds | Level 1

Employee Benefits

Fair value of plan assets

0

^[2]

0

Change in plan assets

Fair value of plan assets at beginning of year

0

Actual return on plan assets:

Fair value of plan assets at end of year

0

^[2]

0

Unfunded Status

Fair value of plan assets

0

^[2]

0

Post-Retirement Benefit Plans | High yield bonds | Level 2

Employee Benefits

Fair value of plan assets

1

^[2]

1

Change in plan assets

Fair value of plan assets at beginning of year

1

Actual return on plan assets:

Fair value of plan assets at end of year

1

^[2]

1

Unfunded Status

Fair value of plan assets

1

^[2]

1

Post-Retirement Benefit Plans | High yield bonds | Level 3

Employee Benefits

Fair value of plan assets

0

^[2]

0

Change in plan assets

Fair value of plan assets at beginning of year

0

Actual return on plan assets:

Fair value of plan assets at end of year

0

^[2]

0

Unfunded Status

Fair value of plan assets

0

^[2]

0

Post-Retirement Benefit Plans | Emerging market bonds

Employee Benefits

Fair value of plan assets valued at NAV

0

Post-Retirement Benefit Plans | Convertible bonds

Employee Benefits

Fair value of plan assets valued at NAV

0

Post-Retirement Benefit Plans | Diversified strategies

Employee Benefits

Fair value of plan assets valued at NAV

54

89

Post-Retirement Benefit Plans | U.S. stocks

Employee Benefits

Fair value of plan assets valued at NAV

0

Fair value of plan assets

35

16

^[5]

35

Change in plan assets

Fair value of plan assets at beginning of year

35

Actual return on plan assets:

Fair value of plan assets at end of year

16

^[5]

35

Unfunded Status

Fair value of plan assets

35

16

^[5]

35

Post-Retirement Benefit Plans | U.S. stocks | Level 1

Employee Benefits

Fair value of plan assets

35

16

^[5]

35

Change in plan assets

Fair value of plan assets at beginning of year

35

Actual return on plan assets:

Fair value of plan assets at end of year

16

^[5]

35

Unfunded Status

Fair value of plan assets

35

16

^[5]

35

Post-Retirement Benefit Plans | U.S. stocks | Level 2

Employee Benefits

Fair value of plan assets

0

^[5]

0

Change in plan assets

Fair value of plan assets at beginning of year

0

Actual return on plan assets:

Fair value of plan assets at end of year

0

^[5]

0

Unfunded Status

Fair value of plan assets

0

^[5]

0

Post-Retirement Benefit Plans | U.S. stocks | Level 3

Employee Benefits

Fair value of plan assets

0

^[5]

0

Change in plan assets

Fair value of plan assets at beginning of year

0

Actual return on plan assets:

Fair value of plan assets at end of year

0

^[5]

0

Unfunded Status

Fair value of plan assets

0

^[5]

0

Post-Retirement Benefit Plans | Non-U.S. stocks

Employee Benefits

Fair value of plan assets valued at NAV

0

Fair value of plan assets

33

12

^[6]

33

Change in plan assets

Fair value of plan assets at beginning of year

33

Actual return on plan assets:

Fair value of plan assets at end of year

12

^[6]

33

Unfunded Status

Fair value of plan assets

33

12

^[6]

33

Post-Retirement Benefit Plans | Non-U.S. stocks | Level 1

Employee Benefits

Fair value of plan assets

33

12

^[6]

33

Change in plan assets

Fair value of plan assets at beginning of year

33

Actual return on plan assets:

Fair value of plan assets at end of year

12

^[6]

33

Unfunded Status

Fair value of plan assets

33

12

^[6]

33

Post-Retirement Benefit Plans | Non-U.S. stocks | Level 2

Employee Benefits

Fair value of plan assets

0

^[6]

0

Change in plan assets

Fair value of plan assets at beginning of year

0

Actual return on plan assets:

Fair value of plan assets at end of year

0

^[6]

0

Unfunded Status

Fair value of plan assets

0

^[6]

0

Post-Retirement Benefit Plans | Non-U.S. stocks | Level 3

Employee Benefits

Fair value of plan assets

0

^[6]

0

Change in plan assets

Fair value of plan assets at beginning of year

0

Actual return on plan assets:

Fair value of plan assets at end of year

0

^[6]

0

Unfunded Status

Fair value of plan assets

0

^[6]

0

Post-Retirement Benefit Plans | Multi-asset strategies

Employee Benefits

Fair value of plan assets valued at NAV

0

Post-Retirement Benefit Plans | Emerging market stocks

Employee Benefits

Fair value of plan assets valued at NAV

0

Fair value of plan assets

6

4

^[10]

6

Change in plan assets

Fair value of plan assets at beginning of year

6

Actual return on plan assets:

Fair value of plan assets at end of year

4

^[10]

6

Unfunded Status

Fair value of plan assets

6

4

^[10]

6

Post-Retirement Benefit Plans | Emerging market stocks | Level 1

Employee Benefits

Fair value of plan assets

6

4

^[10]

6

Change in plan assets

Fair value of plan assets at beginning of year

6

Actual return on plan assets:

Fair value of plan assets at end of year

4

^[10]

6

Unfunded Status

Fair value of plan assets

6

4

^[10]

6

Post-Retirement Benefit Plans | Emerging market stocks | Level 2

Employee Benefits

Fair value of plan assets

0

^[10]

0

Change in plan assets

Fair value of plan assets at beginning of year

0

Actual return on plan assets:

Fair value of plan assets at end of year

0

^[10]

0

Unfunded Status

Fair value of plan assets

0

^[10]

0

Post-Retirement Benefit Plans | Emerging market stocks | Level 3

Employee Benefits

Fair value of plan assets

0

^[10]

0

Change in plan assets

Fair value of plan assets at beginning of year

0

Actual return on plan assets:

Fair value of plan assets at end of year

0

^[10]

0

Unfunded Status

Fair value of plan assets

0

^[10]

0

Post-Retirement Benefit Plans | Private equity

Employee Benefits

Fair value of plan assets valued at NAV

21

28

Post-Retirement Benefit Plans | Private debt

Employee Benefits

Fair value of plan assets valued at NAV

2

3

Post-Retirement Benefit Plans | Market Neutral Hedge Funds

Employee Benefits

Fair value of plan assets valued at NAV

17

25

Post-Retirement Benefit Plans | Directional Hedge Funds

Employee Benefits

Fair value of plan assets valued at NAV

1

Post-Retirement Benefit Plans | Real Estate

Employee Benefits

Fair value of plan assets valued at NAV

20

28

Post-Retirement Benefit Plans | Cash equivalents and short-term investment funds

Employee Benefits

Fair value of plan assets valued at NAV

2

5

Fair value of plan assets

8

4

^[9]

8

Change in plan assets

Fair value of plan assets at beginning of year

8

Actual return on plan assets:

Fair value of plan assets at end of year

4

^[9]

8

Unfunded Status

Fair value of plan assets

8

4

^[9]

8

Post-Retirement Benefit Plans | Cash equivalents and short-term investment funds | Level 1

Employee Benefits

Fair value of plan assets

0

^[9]

0

Change in plan assets

Fair value of plan assets at beginning of year

0

Actual return on plan assets:

Fair value of plan assets at end of year

0

^[9]

0

Unfunded Status

Fair value of plan assets

0

^[9]

0

Post-Retirement Benefit Plans | Cash equivalents and short-term investment funds | Level 2

Employee Benefits

Fair value of plan assets

8

4

^[9]

8

Change in plan assets

Fair value of plan assets at beginning of year

8

Actual return on plan assets:

Fair value of plan assets at end of year

4

^[9]

8

Unfunded Status

Fair value of plan assets

8

4

^[9]

8

Post-Retirement Benefit Plans | Cash equivalents and short-term investment funds | Level 3

Employee Benefits

Fair value of plan assets

0

^[9]

0

Change in plan assets

Fair value of plan assets at beginning of year

0

Actual return on plan assets:

Fair value of plan assets at end of year

0

^[9]

0

Unfunded Status

Fair value of plan assets

$ 0

^[9]

$ 0

[1]	Investment grade bonds represent investments in fixed income securities as well as commingled bond funds comprised of U.S. Treasury securities, agencies, corporate bonds, mortgage-backed securities, asset-backed securities and commercial mortgage-backed securities. Treasury securities are valued at the bid price reported in the active market in which the security is traded and are classified as Level 1. The valuation inputs of other investment grade bonds primarily utilize observable market information and are based on a spread to U.S. Treasury securities and consider yields available on comparable securities of issuers with similar credit ratings. The primary observable inputs include references to the new issue market for similar securities, the secondary trading markets and dealer quotes. Option adjusted spread models are utilized to evaluate securities such as asset backed securities that have early redemption features. These securities are classified as Level 2. The commingled funds are valued at NAV based on the market value of the underlying fixed income securities using the same valuation inputs described above.
[2]	High yield bonds represent investments in below investment grade fixed income securities as well as commingled high yield bond funds. The valuation inputs for the securities primarily utilize observable market information and are based on a spread to U.S. Treasury securities and consider yields available on comparable securities of issuers with similar credit ratings. These securities are primarily classified as Level 2. The commingled funds are valued at NAV based on the market value of the underlying high yield instruments using the same valuation inputs described above.
[3]	Emerging market bonds represent investments in securities issued by governments and other entities located in developing countries as well as registered mutual funds and commingled emerging market bond funds. The valuation inputs for the securities utilize observable market information and are primarily based on dealer quotes or a spread relative to the local government bonds. The registered mutual fund is classified as Level 1 while individual securities are classified as Level 2. The commingled funds are valued at NAV based on the market value of the underlying emerging market bonds using the same valuation inputs described above.
[4]	Convertible bonds primarily represent investments in corporate debt securities that have features that allow the debt to be converted into equity securities under certain circumstances. The valuation inputs for the individual convertible bonds primarily utilize observable market information including a spread to U.S. Treasuries and the value and volatility of the underlying equity security. Convertible bonds are classified as Level 2.
[5]	U.S. stocks represent investments in stocks of U.S. based companies as well as commingled U.S. stock funds. The valuation inputs for U.S. stocks are based on the last published price reported on the major stock market on which the securities are traded and are classified as Level 1. The commingled funds are valued at NAV based on the market value of the underlying investments using the same valuation inputs described above.
[6]	Non-U.S. stocks represent investments in stocks of companies based in developed countries outside the U.S. as well as commingled funds. The valuation inputs for non-U.S. stocks are based on the last published price reported on the major stock market on which the securities are traded and are primarily classified as Level 1. The commingled funds are valued at NAV based on the market value of the underlying investments using the same valuation inputs described above.
[7]	Real estate represents investments in commingled funds and limited partnerships that invest in a diversified portfolio of real estate properties. These investments are valued at NAV according to the valuation policy of each fund or partnership, subject to prevailing accounting and other regulatory guidelines. The valuation inputs of the underlying properties are generally based on third-party appraisals that use comparable sales or a projection of future cash flows to determine fair value.
[8]	Derivatives include exchange traded futures contracts which are classified as Level 1, as well as privately negotiated over-the-counter swaps and options that are valued based on the change in interest rates or a specific market index and are classified as Level 2. The market values represent gains or losses that occur due to fluctuations in interest rates, foreign currency exchange rates, security prices, or other factors.
[9]	Cash equivalents and short-term investments represent investments that are used in conjunction with derivatives positions or are used to provide liquidity for the payment of benefits or other purposes. The valuation inputs of securities are based on a spread to U.S. Treasury Bills, the Federal Funds Rate, or London Interbank Offered Rate and consider yields available on comparable securities of issuers with similar credit ratings and are classified as Level 2. The commingled funds are valued at NAV based on the market value of the underlying investments using the same valuation inputs described above.
[10]	Emerging market stocks represent investments in a registered mutual fund and commingled funds comprised of stocks of companies located in developing markets. Registered mutual funds trade at the daily NAV, as determined by the market value of the underlying investments, and are classified as Level 1. The commingled funds are valued at NAV based on the market value of the underlying investments using the same valuation inputs described previously for individual stocks.

Employee Benefits (Details 3) - 401(k) Defined Contribution Plan - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Contribution Plan Disclosure [Line Items]
Company common stock included in the assets of the 401(k) Plan (in shares)	8	8
Expenses related to the 401(k) Plan	$ 83	$ 81	$ 89

Share-based Compensation (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions		3 Months Ended						6 Months Ended	12 Months Ended
	Mar. 30, 2015	Sep. 30, 2015	Mar. 31, 2015	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Jun. 30, 2013	Jun. 30, 2013	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Summary of stock options weighted-average exercise price activity
Exercisable at December 31, 2015 (in dollars per share)									$ 39.67
Weighted-Average Grant Date Fair Value
Compensation cost									$ 73	$ 75	$ 63
Share-based compensation, aggregate disclosures
Tax benefit recognized in the income statement for share-based payment arrangements									28	$ 29	25
Unrecognized compensation cost									$ 113
Weighted-average recognition period									2 years 6 months
Stock options
Share-based compensation
Option expiration term (in years)									10 years
Summary of stock options activity
Outstanding at December 31, 2014 (in shares)			4,106						4,106
Exercised (in shares)									(335)
Forfeited/Expired (in shares)									(246)
Outstanding at December 31, 2015 (in shares)									3,525	4,106
Exercisable at December 31, 2015 (in shares)									3,525
Summary of stock options weighted-average exercise price activity
Outstanding at December 31, 2014 (in dollars per share)			$ 37.99						$ 37.99
Exercised (in dollars per share)									26.00
Forfeited/Expired (in dollars per share)									30.33
Outstanding at December 31, 2015 (in dollars per share)									$ 39.67	$ 37.99
Stock options aggregate intrinsic value
Outstanding at the end of the period									$ 1
Weighted-average remaining contractual term									1 year 11 months
Net cash proceeds received in connection with option exercises									$ 9
Tax benefit realized from option exercises									1
Total intrinsic value of options exercised									$ 4	$ 9	11
Restricted Stock
Summary of restricted stock and restricted stock unit activity
Nonvested at the beginning of the period (in shares)			4,400						4,400
Granted (in shares)			496			440	335		2,904	2,900
Vested (in shares)									(1,724)
Forfeited (in shares)									(678)
Nonvested at the end of the period (in shares)									4,902	4,400
Weighted-Average Grant Date Fair Value
Nonvested at the beginning of the period (in dollars per share)			$ 36.59						$ 36.59
Granted (in dollars per share)									31.83	$ 35.87
Vested (in dollars per share)									35.71
Forfeited (in dollars per share)									38.95
Nonvested at the end of the period (in dollars per share)									$ 33.86	$ 36.59
Total fair value of awards vested during the period									$ 59	$ 53	$ 52
Employee Stock Purchase Plan
Share-based compensation
Discount given to employees on common stock (as a percent)									15.00%
Period during which lower of beginning and ending stock price is considered for purchase of common stock at discount (in months)									6 months
Service conditions \| Restricted Stock
Restricted stock awards
Period over which total shareholder return will be considered for determining satisfaction of specific performance conditions		3 years							3 years	3 years	3 years
Summary of restricted stock and restricted stock unit activity
Granted (in shares)	1,200		198		1,500	250	223	1,200
Service conditions \| Restricted Stock \| Awards vesting on August 14, 2018
Summary of restricted stock and restricted stock unit activity
Granted (in shares)		193
Service conditions \| Restricted Stock \| Awards vesting on August 14, 2020
Summary of restricted stock and restricted stock unit activity
Granted (in shares)		423
Service conditions \| Restricted Stock \| Awards vesting on August 14, 2022
Summary of restricted stock and restricted stock unit activity
Granted (in shares)		230
Service conditions \| Restricted Stock \| Awards vesting equally on August 14, 2017, 2019 and 2021
Summary of restricted stock and restricted stock unit activity
Granted (in shares)		55
Service conditions \| Restricted Stock \| Awards vesting on August 4, 2017
Summary of restricted stock and restricted stock unit activity
Granted (in shares)				105
Service conditions \| Restricted Stock \| Awards vesting on August 4, 2019
Summary of restricted stock and restricted stock unit activity
Granted (in shares)				325
Service conditions \| Restricted Stock \| Awards vesting on August 4, 2021
Summary of restricted stock and restricted stock unit activity
Granted (in shares)				220
Service conditions \| Restricted Stock \| Minimum
Restricted stock awards
Period over which total shareholder return will be considered for determining satisfaction of specific performance conditions		3 years
Service conditions \| Restricted Stock \| Maximum
Restricted stock awards
Period over which total shareholder return will be considered for determining satisfaction of specific performance conditions		7 years		7 years
Market and service conditions \| Minimum
Restricted stock awards
Percentage of target award (as a percent)			0.00%			0.00%
Market and service conditions \| Maximum
Restricted stock awards
Percentage of target award (as a percent)			200.00%			200.00%
Market and service conditions \| Restricted Stock \| Minimum
Restricted stock awards
Percentage of target award (as a percent)							0.00%
Market and service conditions \| Restricted Stock \| Maximum
Restricted stock awards
Percentage of target award (as a percent)							200.00%

Earnings (Loss) Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income (Loss) (Numerator):
Net income (loss)	$ 338	$ 205	$ 143	$ 192	$ 188	$ 188	$ 193	$ 203	$ 878	$ 772	$ (239)
Earnings applicable to non-vested restricted stock									0	0	0
Net income (loss) applicable to common stock for computing basic earnings (loss) per common share									878	772	(239)
Net income (loss) as adjusted for purposes of computing diluted earnings (loss) per common share									$ 878	$ 772	$ (239)
Weighted average number of shares:
Weighted average shares outstanding for computing basic earnings (loss) per common share (in shares)									554,278	568,435	600,892
Incremental common shares attributable to dilutive securities:
Number of shares as adjusted for purposes of computing diluted earnings (loss) per common share (in shares)									555,093	569,739	600,892
Basic earnings (loss) per common share (in dollars per share)	$ 0.62	$ 0.37	$ 0.26	$ 0.34	$ 0.33	$ 0.33	$ 0.34	$ 0.35	$ 1.58	$ 1.36	$ (0.40)
Diluted earnings (loss) per common share (in dollars per share)	$ 0.62	$ 0.37	$ 0.26	$ 0.34	$ 0.33	$ 0.33	$ 0.34	$ 0.35	$ 1.58	$ 1.36	$ (0.40)
Number of shares of common stock excluded from the computation of diluted earnings per share									3,100	2,500	2,700
Share-based payments and convertible debt securities
Incremental common shares attributable to dilutive securities:
Number of shares of common stock excluded from the computation of diluted earnings per share											1,300
Common Class A
Weighted average number of shares:
Outstanding during period (in shares)									559,260	572,748	604,404
Non-vested restricted stock (in shares)									(4,982)	(4,313)	(3,512)
Weighted average shares outstanding for computing basic earnings (loss) per common share (in shares)									554,278	568,435	600,892
Incremental common shares attributable to dilutive securities:
Shares issuable under convertible securities (in shares)									10	10	0
Shares issuable under incentive compensation plans (in shares)									805	1,294	0
Number of shares as adjusted for purposes of computing diluted earnings (loss) per common share (in shares)									555,093	569,739	600,892

Fair Value Disclosure (Details) - Fair Value Measurements valued on recurring basis - Fair value, Input Level 2 - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Reported Value Measurement [Member]
Liabilities
Liabilities-Long-term debt excluding capital lease and other obligations	$ 19,800	$ 19,994
Estimate of Fair Value Measurement [Member]
Liabilities
Liabilities-Long-term debt excluding capital lease and other obligations	$ 19,473	$ 21,255

Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
Income Taxes (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Federal
Current			$ 28	$ 18	$ 1
Deferred			329	305	403
State
Current			40	26	62
Deferred			21	(14)	(8)
Foreign
Current			16	3	9
Deferred			4	0	(4)
Total income tax expense			438	338	463
Income tax expense allocation
Attributable to income			438	338	463
Stockholders' equity:
Compensation expense for tax purposes in excess of amounts recognized for financial reporting purposes			(5)	(5)	(14)
Tax effect of the change in accumulated other comprehensive loss			$ 59	$ (744)	$ 554
Reconciliation of the statutory federal income tax rate to effective income tax rate
Statutory federal income tax rate (as a percent)			35.00%	35.00%	35.00%
State income taxes, net of federal income tax benefit (as a percent)			2.60%	2.70%	2.80%
Impairment of goodwill (as a percent)			0.00%	0.00%	188.50%
Change in liability for unrecognized tax position (as a percent)			0.40%	0.40%	(24.50%)
Foreign income taxes (as a percent)			0.70%	0.40%	2.70%
Nondeductible accounting adjustment for life insurance (as a percent)			0.00%	0.00%	3.10%
Affiliate debt rationalization, (as a percent)			(2.60%)	(0.00%)	(0.00%)
Release state valuation allowance (as a percent)			0.00%	0.00%	(2.30%)
Research and development credits (as a percent)			(2.10%)	(0.00%)	(0.00%)
Loss on worthless investment in foreigh subsidiary (as a percent)			0.00%	(5.40%)	0.00%
Other, net (as a percent)			(0.70%)	(2.60%)	1.40%
Effective income tax rate (as a percent)			33.30%	30.50%	206.70%
Affiliate debt rationalization	$ 34		$ 34
Research and development credits	28		28
Changes affecting state income taxes	(16)		16	$ 13
Loss on worthless investment in foreign subsidiary		$ (60)
Impairment of goodwill					$ 1,092
Tax settlement with domestic tax authority					(33)
Reversal of liability for unrecognized tax position					22
Nondeductible accounting adjustment for life insurance					17
Release state valuation allowance					5
Deferred tax assets
Post-retirement and pension benefit costs	2,154	2,276	2,154	2,276
Net operating loss carryforwards	487	1,091	487	1,091
Other employee benefits	182	214	182	214
Other	458	602	458	602
Gross deferred tax assets	3,281	4,183	3,281	4,183
Less valuation allowance	(380)	(409)	(380)	(409)
Net deferred tax assets	2,901	3,774	2,901	3,774
Deferred tax liabilities
Property, plant and equipment, primarily due to depreciation differences	(3,841)	(3,869)	(3,841)	(3,869)
Goodwill and other intangible assets	(2,588)	(2,908)	(2,588)	(2,908)
Other	(38)	(147)	(38)	(147)
Gross deferred tax liabilities	(6,467)	(6,924)	(6,467)	(6,924)
Net deferred tax liabilities	(3,566)	(3,150)	(3,566)	(3,150)
Long-term deferred tax liability, net	3,569	3,154	3,569	3,154
Noncurrent deferred tax asset, net	3	4	3	4
Summary of reconciliation of the change in gross unrecognized tax benefits activity
Unrecognized tax benefits, beginning of year			17	14
Increase in tax positions taken in current year			1	0
Increase in tax positions taken in the prior year			7	9
Decrease due to the reversal of tax positions taken in a prior year			(9)	(2)
Decrease from the lapse of statute of limitations			(1)	(1)
Settlements			0	(3)
Unrecognized tax benefits, end of year	15	17	15	17	$ 14
Unrecognized tax benefits that would impact effective tax rate	32	32	32	32
Interest on income taxes accrued	33	$ 30	33	$ 30
Significant change in unrecorded benefit	11		11
Federal
NOLs
Operating loss carryforward	72		72
State
NOLs
Operating loss carryforward	$ 13,000		$ 13,000

Income Taxes (Details 2) - USD ($) $ in Millions	12 Months Ended
Income Taxes (Details 2) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Income taxes
Valuation allowance	$ 380	$ 409
Deferred tax asset valuation allowance adjustment	29
Federal
Income taxes
Tax credit carryforwards	28
Investment tax credits \| State
Income taxes
Tax credit carryforwards	36
Tax credit carryforwards, net of federal income tax	23
Alternative minimum tax credits
Income taxes
Tax credit carryforwards	$ 79

Segment Information (Details) $ in Millions	3 Months Ended								12 Months Ended
Segment Information (Details) $ in Millions	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Sep. 30, 2014 USD ($)	Jun. 30, 2014 USD ($)	Mar. 31, 2014 USD ($)	Dec. 31, 2015 USD ($) segment	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Segment Reporting Information [Line Items]
Operating revenues	$ 4,476	$ 4,554	$ 4,419	$ 4,451	$ 4,438	$ 4,514	$ 4,541	$ 4,538	$ 17,900	$ 18,031	$ 18,095
Expenses									15,295	15,621	16,642
OPERATING INCOME	$ 751	$ 656	$ 549	$ 649	$ 483	$ 619	$ 655	$ 653	$ 2,605	2,410	1,453
Number of reportable segments (segments) \| segment									2
Operating segments (segments)
Segment Reporting Information [Line Items]
Operating revenues									$ 16,668	17,028	17,095
Expenses									8,459	8,509	8,167
OPERATING INCOME									$ 8,209	$ 8,519	$ 8,928
Margin percentage (percent)									49.00%	50.00%	52.00%
Business
Segment Reporting Information [Line Items]
Operating revenues									$ 10,647	$ 11,034	$ 11,091
Expenses									6,034	6,089	5,808
OPERATING INCOME									$ 4,613	$ 4,945	$ 5,283
Margin percentage (percent)									43.00%	45.00%	48.00%
Consumer
Segment Reporting Information [Line Items]
Operating revenues									$ 6,021	$ 5,994	$ 6,004
Expenses									2,425	2,420	2,359
OPERATING INCOME									$ 3,596	$ 3,574	$ 3,645
Margin percentage (percent)									60.00%	60.00%	61.00%

Segment Information (Details 2) $ in Millions	3 Months Ended								12 Months Ended
Segment Information (Details 2) $ in Millions	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Sep. 30, 2014 USD ($)	Jun. 30, 2014 USD ($)	Mar. 31, 2014 USD ($)	Dec. 31, 2015 USD ($) category	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Operating revenues by products and services
Operating revenues	$ 4,476	$ 4,554	$ 4,419	$ 4,451	$ 4,438	$ 4,514	$ 4,541	$ 4,538	$ 17,900	$ 18,031	$ 18,095
Surcharge amount on customers' bills									$ 544	526	489
Number of categories of products and services (categories) \| category									4
Strategic services
Operating revenues by products and services
Operating revenues									$ 9,343	9,166	8,776
Strategic services \| Products and services revenue reclassification \| Restatement adjustment
Operating revenues by products and services
Operating revenues										(34)	(47)
Facilities-based video services
Operating revenues by products and services
Number of markets	16								16
Legacy services
Operating revenues by products and services
Operating revenues									$ 6,752	7,172	7,663
Legacy services \| Products and services revenue reclassification \| Restatement adjustment
Operating revenues by products and services
Operating revenues										34	47
Data integration
Operating revenues by products and services
Operating revenues									573	690	656
High-cost support revenue
Operating revenues by products and services
Operating revenues									732	528	547
Other revenue
Operating revenues by products and services
Operating revenues									500	475	453
Total other revenues
Operating revenues by products and services
Operating revenues									1,232	1,003	1,000
Business
Operating revenues by products and services
Operating revenues									10,647	11,034	11,091
Business \| Data integration
Operating revenues by products and services
Operating revenues									571	686	651
Business \| High-bandwidth data services
Operating revenues by products and services
Operating revenues									2,816	2,579	2,230
Business \| Low-bandwidth data services
Operating revenues by products and services
Operating revenues									2,052	2,345	2,577
Business \| Hosting services
Operating revenues by products and services
Operating revenues									1,281	1,316	1,259
Business \| Other business strategic services
Operating revenues by products and services
Operating revenues									162	76	60
Business \| Voice services
Operating revenues by products and services
Operating revenues									2,590	2,780	2,916
Business \| Other business legacy services
Operating revenues by products and services
Operating revenues									1,175	1,252	1,398
Consumer
Operating revenues by products and services
Operating revenues									6,021	5,994	6,004
Consumer \| Data integration
Operating revenues by products and services
Operating revenues									2	4	5
Consumer \| High-speed Internet services
Operating revenues by products and services
Operating revenues									2,611	2,469	2,358
Consumer \| Other consumer strategic services
Operating revenues by products and services
Operating revenues									421	381	292
Consumer \| Voice services
Operating revenues by products and services
Operating revenues									2,676	2,864	3,101
Consumer \| Other consumer legacy services
Operating revenues by products and services
Operating revenues									$ 311	$ 276	$ 248

Segment Information (Details 3) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
Segment Information (Details 3) - USD ($) $ in Millions	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total segment income	$ 751	$ 656	$ 549	$ 649	$ 483	$ 619	$ 655	$ 653	$ 2,605	$ 2,410	$ 1,453
Depreciation and amortization									(4,189)	(4,428)	(4,541)
Impairment of goodwill									0	0	(1,092)
Other unassigned operating expenses									(3,328)	(3,347)	(3,502)
Income tax expense									(438)	(338)	(463)
Other expenses, net									(1,289)	(1,300)	(1,229)
Net income (loss)	$ 338	$ 205	$ 143	$ 192	$ 188	$ 188	$ 193	$ 203	878	772	(239)
Operating segments (segments)
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total segment income									8,209	8,519	8,928
Unallocated amount to segment
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Other operating revenues									1,232	1,003	1,000
Depreciation and amortization									(4,189)	(4,428)	(4,541)
Impairment of goodwill									0	0	(1,092)
Other unassigned operating expenses									(2,647)	(2,684)	(2,842)
Income tax expense									(438)	(338)	(463)
Other expenses, net									$ (1,289)	$ (1,300)	$ (1,229)

Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Quarterly Financial Information Disclosure [Abstract]
Operating revenues	$ 4,476	$ 4,554	$ 4,419	$ 4,451	$ 4,438	$ 4,514	$ 4,541	$ 4,538	$ 17,900	$ 18,031	$ 18,095
OPERATING INCOME	751	656	549	649	483	619	655	653	2,605	2,410	1,453
Net income (loss)	$ 338	$ 205	$ 143	$ 192	$ 188	$ 188	$ 193	$ 203	$ 878	$ 772	$ (239)
Basic earnings (loss) per common share (in dollars per share)	$ 0.62	$ 0.37	$ 0.26	$ 0.34	$ 0.33	$ 0.33	$ 0.34	$ 0.35	$ 1.58	$ 1.36	$ (0.40)
Diluted earnings (loss) per common share (in dollars per share)	$ 0.62	$ 0.37	$ 0.26	$ 0.34	$ 0.33	$ 0.33	$ 0.34	$ 0.35	$ 1.58	$ 1.36	$ (0.40)
Incremental increase in other operating revenues	$ 57	$ 158
Affiliate debt rationalization	34								$ 34
Research and development credits	28								28
Changes affecting state income taxes	$ 16								$ (16)	$ (13)
Loss on worthless investment in foreign subsidiary					$ 60
Settlements					$ (63)

Commitments and Contingencies (Details)			12 Months Ended			24 Months Ended
Commitments and Contingencies (Details)	Jul. 16, 2013 USD ($)	Oct. 14, 2011 plaintiff	Dec. 31, 2015 USD ($) plaintiff	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Dec. 31, 2007 USD ($)
Commitments and Contingencies
Number of patents allegedly infringed, minimum			1
Capital lease activity
Assets acquired through capital leases			$ 17,000,000	$ 37,000,000	$ 12,000,000
Depreciation expense			96,000,000	126,000,000	136,000,000
Cash payments towards capital leases			89,000,000	118,000,000	119,000,000
Assets included in property, plant and equipment			722,000,000	850,000,000
Accumulated depreciation			352,000,000	393,000,000
Future annual minimum payments under capital lease arrangements
2016			85,000,000
2017			78,000,000
2018			76,000,000
2019			62,000,000
2020			47,000,000
2021 and thereafter			223,000,000
Total minimum payments			571,000,000
Less: amount representing interest and executory costs			(153,000,000)
Present value of minimum payments			418,000,000
Less: current portion			(56,000,000)
Long-term portion			362,000,000
Operating Leases
Rent expense			467,000,000	446,000,000	455,000,000
Sublease rental income			12,000,000	$ 14,000,000	$ 16,000,000
Future rental commitments
2016			301,000,000
2017			289,000,000
2018			268,000,000
2019			235,000,000
2020			209,000,000
2021 and thereafter			1,075,000,000
Total future minimum payments			2,377,000,000
Minimum sublease rentals due in the future under non-cancelable subleases			87,000,000
Purchase obligations maturities
Total purchase commitments			625,000,000
2016			364,000,000
2017 and 2018			144,000,000
2019 and 2020			46,000,000
2021 and thereafter			$ 71,000,000
William Douglas Fulghum, et al. v. Embarq Corporation
Commitments and Contingencies
Effect of modifications made to Embarq's benefits program, greater than						$ 300,000,000
Number of plaintiffs have alleged breach of fiduciary duty (plaintiffs) \| plaintiff			15
Abbott et al. v. Sprint Nextel et al.
Commitments and Contingencies
Number of plaintiffs have alleged breach of fiduciary duty (plaintiffs)		1,500
Number of Plaintiffs, Limited Discovery \| plaintiff		80
Comcast MO Group, Inc. \| Qwest Communications International Inc
Litigation Matters Assumed in Qwest Acquisition
Damages sought by plaintiff	$ 80,000,000
Unfavorable regulatory action
Litigation Matters Assumed in Qwest Acquisition
Reasonable expectation of loss, maximum per proceeding			$ 100,000

Other Financial Information Other Financial Information (Details) - USD ($) $ in Millions		1 Months Ended	12 Months Ended
	Nov. 03, 2014	Jan. 31, 2013	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Prepaid Expenses and Other Current Assets [Abstract]
Prepaid expenses			$ 238	$ 260
Materials, supplies and inventory			144	132
Assets held for sale			8	14
Deferred activation and installation charges			105	103
Other			86	71
Other Assets, Current			581	580
Assets Held-for-sale, Not Part of Disposal Group, Current [Abstract]
Impairment wireless spectrum licenses				14
Proceeds from sale of wireless spectrum	$ 39
Wireless spectrum licenses		$ 43
Gain sale of wireless spectrum		$ 32	0	0	$ 32
Accounts Payable, Current [Abstract]
Accounts payable			968	1,226
Capital expenditures included in accounts payable			94	185
Book overdraft balance			68	80
Other current liabilities:
Accrued rent			32	34
Legal reserves			20	27
Other			168	149
Total other current liabilities			$ 220	$ 210

Labor Union Contracts (Details)	12 Months Ended
Labor Union Contracts (Details)	Dec. 31, 2015 Employee
Employees subject to collective bargaining arrangements that have expired
Labor Union Contracts
Number of unionized employees	300
Employees subject to collective bargaining arrangements expiring within one year
Labor Union Contracts
Number of unionized employees	1,000
Total number of employees \| Unionized employees concentration risk
Labor Union Contracts
Concentration risk (percent)	37.00%
Total number of employees \| Unionized employees concentration risk \| Employees subject to collective bargaining arrangements that have expired
Labor Union Contracts
Concentration risk (percent)	2.00%
Total number of employees \| Unionized employees concentration risk \| Employees subject to collective bargaining arrangements expiring within one year
Labor Union Contracts
Concentration risk (percent)	6.00%

Repurchase of CenturyLink Common Stock (Details) - Share repurchase program authorized February 2014 - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended	18 Months Ended
	Dec. 31, 2015	Dec. 07, 2015	Feb. 28, 2014
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program, period in force	24 months
Stock repurchases, aggregate authorized amount			$ 1,000
Stock repurchased and retired during period, shares	27.1	32.3
Stock repurchased and retired during period, value	$ 800
Stock repurchased and retired during period, average cost per share	$ 29.56	$ 30.99

Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Accumulated other comprehensive income (loss) by component
Balance at December 31, 2014	$ (2,017)	$ (802)
OCI, before Reclassifications, Net of Tax, Attributable to Parent	(32)	(1,284)
Reclassification from AOCI, Current Period, Net of Tax, Attributable to Parent	115	69
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	83	(1,215)
Balance at December 31, 2015	(1,934)	(2,017)
Foreign Currency Translation Adjustment and Other
Accumulated other comprehensive income (loss) by component
Balance at December 31, 2014	(25)	(11)
OCI, before Reclassifications, Net of Tax, Attributable to Parent	(14)	(15)
Reclassification from AOCI, Current Period, Net of Tax, Attributable to Parent	0	1
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(14)	(14)
Balance at December 31, 2015	(39)	(25)
Defined Benefit Plans \| Pension Plan
Accumulated other comprehensive income (loss) by component
Balance at December 31, 2014	(1,720)	(669)
OCI, before Reclassifications, Net of Tax, Attributable to Parent	(98)	(1,107)
Reclassification from AOCI, Current Period, Net of Tax, Attributable to Parent	103	56
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	5	(1,051)
Balance at December 31, 2015	(1,715)	(1,720)
Defined Benefit Plans \| Post-Retirement Benefit Plans
Accumulated other comprehensive income (loss) by component
Balance at December 31, 2014	(272)	(122)
OCI, before Reclassifications, Net of Tax, Attributable to Parent	80	(162)
Reclassification from AOCI, Current Period, Net of Tax, Attributable to Parent	12	12
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	92	(150)
Balance at December 31, 2015	$ (180)	$ (272)

- Definition

Accumulated change in equity from transactions and other events and circumstances from non-owner sources, net of tax effect, at period end. Excludes Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge.

+ References + Details

Accumulated Other Comprehensive Loss (Details 2) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
INCOME BEFORE INCOME TAX EXPENSE									$ (1,316)	$ (1,110)	$ (224)
Income tax expense									(438)	(338)	(463)
Other income, net									23	11	59
NET INCOME (LOSS)	$ 338	$ 205	$ 143	$ 192	$ 188	$ 188	$ 193	$ 203	878	772	$ (239)
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net actuarial loss									161	(85)
Prior service cost									24	(25)
INCOME BEFORE INCOME TAX EXPENSE									(185)	110
Income tax expense									(70)	42
Other income, net										1
NET INCOME (LOSS)									$ 115	$ 69

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References + Details

Dividends (Details) - USD ($)	Nov. 10, 2015	Aug. 25, 2015	May. 20, 2015	Feb. 23, 2015	Nov. 11, 2014	Aug. 19, 2014	May. 28, 2014	Feb. 24, 2014
Dividends, Common Stock [Abstract]
Dividend per share (usd per share)	$ 0.54	$ 0.54	$ 0.54	$ 0.54	$ 0.54	$ 0.54	$ 0.54	$ 0.54
Total amount declared	$ 293,000,000	$ 300,000,000	$ 303,000,000	$ 303,000,000	$ 307,000,000	$ 308,000,000	$ 307,000,000	$ 309,000,000