Lumen (LUMN) 10-K 25 Feb 16 2015 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2015	Feb. 17, 2016	Jun. 30, 2015
Document and Entity Information
Entity Registrant Name	CENTURYLINK, INC
Entity Central Index Key	18,926
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	2,015
Document Fiscal Period Focus	FY

CONSOLIDATED STATEMENTS OF OPER

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 COMP

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

CONSOLIDATED STATEMENTS OF COM4

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

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 (Pa

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	$ 25
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	$ 1
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

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 CAS8

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 STOC

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 Summa

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 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 Relationship

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 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.

Long-Term Debt and Credit Facil

Long-Term Debt and Credit Facilities	12 Months Ended
	Dec. 31, 2015
Debt Disclosure [Abstract]
Long-Term Debt and Credit Facilities	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

Accounts Receivable	12 Months Ended
	Dec. 31, 2015
Receivables [Abstract]
Accounts Receivable	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

Property, Plant and Equipment	12 Months Ended
	Dec. 31, 2015
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	Property, Plant and Equipment Net property, plant and equipment is composed of the following: Depreciable Lives As of December 31, 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 Estat

Severance and Leased Real Estate	12 Months Ended
	Dec. 31, 2015
Restructuring and Related Activities [Abstract]
Severance and Leased Real Estate	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

Employee Benefits	12 Months Ended
	Dec. 31, 2015
Compensation and Retirement Disclosure [Abstract]
Employee Benefits	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 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 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 a

Share-based Compensation

Share-based Compensation	12 Months Ended
	Dec. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-based Compensation	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 Shar

Earnings (Loss) Per Common Share	12 Months Ended
	Dec. 31, 2015
Earnings Per Share [Abstract]
Earnings (Loss) Per Common Share	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

Fair Value Disclosure	12 Months Ended
	Dec. 31, 2015
Fair Value Disclosures [Abstract]
Fair Value Disclosure	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

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Income Taxes	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

Segment Information	12 Months Ended
	Dec. 31, 2015
Segment Reporting [Abstract]
Segment Information	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.

Quarterly Financial Data (Unaud

Quarterly Financial Data (Unaudited)	12 Months Ended
	Dec. 31, 2015
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Data (Unaudited)	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

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	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

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

Labor Union Contracts	12 Months Ended
	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 Commo

Repurchase of CenturyLink Common Stock	12 Months Ended
	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

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

Dividends

Dividends	12 Months Ended
	Dec. 31, 2015
Dividends, Common Stock [Abstract]
Dividends	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.

Basis of Presentation and Sum29

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	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	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	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	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	Legal Costs In the normal course of our business, we incur costs to hire and retain external legal counsel to advise us on regulatory, litigation and other matters. We expense these costs as the related services are received.
Income Taxes	Income Taxes 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 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 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 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	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	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	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 Relationsh30

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 Fac31

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

Accounts Receivable (Tables)

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 (

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, 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 Est34

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)

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 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 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 (Table

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 Sh37

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)

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)

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)

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 (Una41

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 (

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 (Ta

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 Comprehensi44

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)

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 Sum46

Basis of Presentation and Summary of Significant Accounting Policies Basis of Presentation and Summary of Significant Accounting Policies (Details) $ in Millions	Aug. 27, 2015USD ($)	Dec. 31, 2015USD ($)state	Sep. 30, 2015USD ($)	Dec. 31, 2015USD ($)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 Sum47

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

Basis of Presentation and Sum48

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 Sum49

Basis of Presentation and Summary of Significant Accounting Policies (Details 4) $ in Millions	12 Months Ended
	Dec. 31, 2015USD ($)
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 Sum50

Basis of Presentation and Summary of Significant Accounting Policies (Details 5) shares in Millions	Dec. 31, 2015$ / sharesshares
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 Sum51

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 Relationsh52

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 Relationsh53

Goodwill, Customer Relationships and Other Intangible Assets (Details 2) $ in Millions	Dec. 31, 2015USD ($)
Expected amortization expense
2,016	$ 1,161
2,017	1,056
2,018	944
2,019	827
2,020	$ 726

Goodwill, Customer Relationsh54

Goodwill, Customer Relationships and Other Intangible Assets Goodwill, Customer Relationships and Other Intangible Assets (Details 3) $ in Millions	Oct. 31, 2015	Oct. 31, 2014	Sep. 30, 2013	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)
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 Relationsh55

Goodwill, Customer Relationships and Other Intangible Assets (Details 4) - USD ($) $ in Millions	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 Relationsh56

Goodwill, Customer Relationships and Other Intangible Assets Goodwill, Customer Relationships and Other Intangible Assets (Details 5) $ in Millions	12 Months Ended
	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
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 Fac57

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	2,669
Embarq Corporation | First mortgage bonds
Long-term Debt and Credit Facilities
Total long-term debt		232	232
Embarq Corporation | Other
Long-term Debt and Credit Facilities
Total long-term debt		$ 150	$ 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 Fac58

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

Jan. 31, 2016USD ($)

Sep. 21, 2015USD ($)

Mar. 19, 2015USD ($)

Feb. 20, 2015USD ($)

Dec. 03, 2014USD ($)lender

Sep. 29, 2014USD ($)

Jan. 31, 2015USD ($)

Dec. 31, 2015USD ($)

Dec. 31, 2014USD ($)

Dec. 31, 2013USD ($)

Oct. 13, 2015USD ($)

Sep. 30, 2015USD ($)

Jun. 15, 2015USD ($)

Feb. 15, 2015USD ($)

Oct. 01, 2014USD ($)

Apr. 01, 2014USD ($)

Apr. 30, 2011USD ($)

Long-term Debt and Credit Facilities

Total long-term debt

[1]

$ 20,529

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

Repayments of long-term debt

$ 966

800

$ 2,010

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

Senior notes | Qwest Corporation

Long-term Debt and Credit Facilities

Total long-term debt

$ 7,229

7,311

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

$ 10

Interest rate, stated percentage (as a percent)

6.625%

Net proceeds from issuance of debt

$ 386

Senior notes | Qwest Corporation | 6.875% Notes due 2054

Long-term Debt and Credit Facilities

Aggregate principal amount of debt issuance

$ 500

Interest rate, stated percentage (as a percent)

6.875%

Net proceeds from issuance of debt

$ 483

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

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

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

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

Senior notes | CenturyLink, Inc.

Long-term Debt and Credit Facilities

Total long-term debt

$ 7,975

7,825

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

Interest rate, stated percentage (as a percent)

5.625%

Net proceeds from issuance of debt

$ 494

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

Senior notes | Embarq Corporation

Long-term Debt and Credit Facilities

Total long-term debt

$ 2,669

2,669

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

Medium-term notes | Qwest Corporation | Term loan

Long-term Debt and Credit Facilities

Aggregate principal amount of debt issuance

$ 100

Total long-term debt

100

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

380

Line of credit | CenturyLink, Inc.

Long-term Debt and Credit Facilities

Total long-term debt

410

725

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

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

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

Long-term Debt and Credit Facilities

Interest rate margin (as a percent)

0.00%

Line of credit | CenturyLink, Inc. | Credit Facility | Revolving credit facility | Minimum | London Interbank Offered Rate (LIBOR)

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

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

Long-term Debt and Credit Facilities

Interest rate margin (as a percent)

1.25%

Line of credit | CenturyLink, Inc. | Credit Facility | Revolving credit facility | Maximum | London Interbank Offered Rate (LIBOR)

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

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

Long-term Debt and Credit Facilities

Total long-term debt

80

Maximum borrowing capacity

$ 100

Number of lenders of revolving line of credit

1

Line of credit | CenturyLink, Inc. | Uncommitted revolving line of credit | Line of credit | Minimum | London Interbank Offered Rate (LIBOR)

Long-term Debt and Credit Facilities

Interest rate margin (as a percent)

1.00%

Line of credit | CenturyLink, Inc. | Uncommitted revolving line of credit | Line of credit | Maximum | London Interbank Offered Rate (LIBOR)

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

232

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

Other | Embarq Corporation

Long-term Debt and Credit Facilities

Interest rate, stated percentage (as a percent)

9.00%

Total long-term debt

$ 150

150

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

Long-term Debt and Credit Facilities

Maximum borrowing capacity

$ 160

Letters of credit outstanding

$ 109

$ 124

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

Long-term Debt and Credit Facilities

Aggregate principal amount of debt issuance

$ 235

Interest rate, stated percentage (as a percent)

7.00%

Net proceeds from issuance of debt

$ 227

[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 Fac59

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 Fac60

Long-Term Debt and Credit Facilities (Details 4) $ in Millions	Dec. 31, 2015USD ($)	[1]
Long-term Debt, Fiscal Year Maturity [Abstract]
2,016	$ 1,503
2,017	1,501
2,018	251
2,019	1,160
2,020	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.

Accounts Receivable (Details)

Accounts Receivable (Details) - USD ($) $ in Millions	12 Months Ended
	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 Equipment62

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 Equipment63

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 Est64

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)

Employee Benefits (Details) - USD ($) $ in Millions		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			$ 16,916		$ 18,872	$ 18,872		$ 17,089		$ 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														2,025		2,024	2,022
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														2,025		2,024	2,022
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														2,025		2,024	2,022
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		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			11,072		12,571	12,571		12,346		12,321		11,072		12,571	$ 12,346
Benefit obligation		13,349			13,349		15,042	$ 15,042		$ 13,401		$ 14,881		13,349		$ 15,042	13,401
Estimated future benefit payments:
2,016														1,059
2,017														1,010
2,018														991
2,019														973
2,020														954
2021 - 2025														$ 4,433
Actuarial assumptions at beginning of year:
Rate of compensation increase (as a percent)								3.25%		3.25%		3.25%
Expected long-term rate of return on plan assets (as a percent)								7.50%		7.50%		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		5		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%		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		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%		7.50%		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			1,201		1,390	$ 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			1,128		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:
2,016														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			193		353	353		535		626		193		353	535
Benefits paid, net of participant contributions and direct subsidy receipts								116
Benefit obligation		3,567			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%		4.50%		4.50%
Year that health care cost rate reaches ultimate trend rate														2,025		2,024
Estimated future benefit payments:
2,016														$ 309
2,017														300
2,018														290
2,019														283
2,020														276
2021 - 2025														1,256
Medicare Part D Subsidy Receipts
2,016														(7)
2,017														(7)
2,018														(7)
2,019														(7)
2,020														(7)
2021 - 2025														$ (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%		4.50%		4.50%
Year that health care cost rate reaches ultimate trend rate														2,025		2,024
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		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%		4.50%		4.50%
Year that health care cost rate reaches ultimate trend rate														2,025		2,024
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	33		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%		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%		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)

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		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		5		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		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		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		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		2,346			1,886		2,346
Pension Plan | Investment grade bonds | Level 1
Employee Benefits
Fair value of plan assets	[1]	1,068		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		1,068			841		1,068
Pension Plan | Investment grade bonds | Level 2
Employee Benefits
Fair value of plan assets	[1]	1,278		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		1,278			1,045		1,278
Pension Plan | Investment grade bonds | Level 3
Employee Benefits
Fair value of plan assets	[1]	0		0			0		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		0
Unfunded Status
Fair value of plan assets	[1]	0		0			0		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		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		654			557		654
Pension Plan | High yield bonds | Level 1
Employee Benefits
Fair value of plan assets	[2]	0		0			0		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		0
Unfunded Status
Fair value of plan assets	[2]	0		0			0		0
Pension Plan | High yield bonds | Level 2
Employee Benefits
Fair value of plan assets	[2]	647		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		647			544		647
Pension Plan | High yield bonds | Level 3
Employee Benefits
Fair value of plan assets		7	[2]	0		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		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		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		615			441		615
Pension Plan | Emerging market bonds | Level 1
Employee Benefits
Fair value of plan assets	[3]	208		208			208		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		208
Unfunded Status
Fair value of plan assets	[3]	208		208			208		208
Pension Plan | Emerging market bonds | Level 2
Employee Benefits
Fair value of plan assets	[3]	407		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		407			232		407
Pension Plan | Emerging market bonds | Level 3
Employee Benefits
Fair value of plan assets		0	[3]	0		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		0
Dispositions		0		0
Actual return on plan assets:
Gains relating to assets sold during the year		0		0
(Losses) gains relating to assets still held at year-end		0		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		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		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		4			2		4
Pension Plan | Convertible bonds | Level 1
Employee Benefits
Fair value of plan assets	[4]	0		0			0		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		0
Unfunded Status
Fair value of plan assets	[4]	0		0			0		0
Pension Plan | Convertible bonds | Level 2
Employee Benefits
Fair value of plan assets	[4]	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		4			2		4
Pension Plan | Convertible bonds | Level 3
Employee Benefits
Fair value of plan assets	[4]	0		0			0		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		0
Unfunded Status
Fair value of plan assets	[4]	0		0			0		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		1,390			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		1,390			1,201		1,390
Pension Plan | U.S. stocks | Level 1
Employee Benefits
Fair value of plan assets	[5]	1,389		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		1,389			1,201		1,389
Pension Plan | U.S. stocks | Level 2
Employee Benefits
Fair value of plan assets	[5]	1		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		1			0		1
Pension Plan | U.S. stocks | Level 3
Employee Benefits
Fair value of plan assets	[5]	0		0			0		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		0
Unfunded Status
Fair value of plan assets	[5]	0		0			0		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		1,170			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		1,170			1,128		1,170
Pension Plan | Non-U.S. stocks | Level 1
Employee Benefits
Fair value of plan assets	[6]	1,169		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		1,169			1,127		1,169
Pension Plan | Non-U.S. stocks | Level 2
Employee Benefits
Fair value of plan assets	[6]	1		1			1		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		1
Unfunded Status
Fair value of plan assets	[6]	1		1			1		1
Pension Plan | Non-U.S. stocks | Level 3
Employee Benefits
Fair value of plan assets	[6]	0		0			0		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		0
Unfunded Status
Fair value of plan assets	[6]	0		0			0		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					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					376
Pension Plan | Multi-asset strategies | Level 1
Employee Benefits
Fair value of plan assets	[6]	376					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					376
Pension Plan | Multi-asset strategies | Level 2
Employee Benefits
Fair value of plan assets	[6]	0					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					0
Pension Plan | Multi-asset strategies | Level 3
Employee Benefits
Fair value of plan assets	[6]	0					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					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		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		17			(4)		17
Pension Plan | Derivatives | Level 1
Employee Benefits
Fair value of plan assets	[8]	2		2			2		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		2
Unfunded Status
Fair value of plan assets	[8]	2		2			2		2
Pension Plan | Derivatives | Level 2
Employee Benefits
Fair value of plan assets	[8]	15		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		15			(6)		15
Pension Plan | Derivatives | Level 3
Employee Benefits
Fair value of plan assets	[8]	0		0			0		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		0
Unfunded Status
Fair value of plan assets	[8]	0		0			0		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		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		626			192		626
Pension Plan | Cash equivalents and short-term investment funds | Level 1
Employee Benefits
Fair value of plan assets	[9]	0		0			0		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		0
Unfunded Status
Fair value of plan assets	[9]	0		0			0		0
Pension Plan | Cash equivalents and short-term investment funds | Level 2
Employee Benefits
Fair value of plan assets	[9]	626		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		626			192		626
Pension Plan | Cash equivalents and short-term investment funds | Level 3
Employee Benefits
Fair value of plan assets	[9]	0		0			0		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		0
Unfunded Status
Fair value of plan assets	[9]	0		0			0		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		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		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		0
Post-Retirement Benefit Plans | Interest rate swaps
Employee Benefits
Gross notional exposure							0		0
Post-Retirement Benefit Plans | Credit default swaps
Employee Benefits
Gross notional exposure							0		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		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		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		6			3	[1]	6
Post-Retirement Benefit Plans | Investment grade bonds | Level 1
Employee Benefits
Fair value of plan assets		5		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		5			2	[1]	5
Post-Retirement Benefit Plans | Investment grade bonds | Level 2
Employee Benefits
Fair value of plan assets		1		1			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	[1]	1
Post-Retirement Benefit Plans | Investment grade bonds | Level 3
Employee Benefits
Fair value of plan assets		0		0			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		0			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		1			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		1			1	[2]	1
Post-Retirement Benefit Plans | High yield bonds | Level 1
Employee Benefits
Fair value of plan assets		0		0			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		0			0	[2]	0
Post-Retirement Benefit Plans | High yield bonds | Level 2
Employee Benefits
Fair value of plan assets		1		1			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		1			1	[2]	1
Post-Retirement Benefit Plans | High yield bonds | Level 3
Employee Benefits
Fair value of plan assets		0		0			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		0			0	[2]	0
Post-Retirement Benefit Plans | Emerging market bonds
Employee Benefits
Fair value of plan assets valued at NAV							0		0
Post-Retirement Benefit Plans | Convertible bonds
Employee Benefits
Fair value of plan assets valued at NAV							0		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		0
Fair value of plan assets		35		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		35			16	[5]	35
Post-Retirement Benefit Plans | U.S. stocks | Level 1
Employee Benefits
Fair value of plan assets		35		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		35			16	[5]	35
Post-Retirement Benefit Plans | U.S. stocks | Level 2
Employee Benefits
Fair value of plan assets		0		0			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		0			0	[5]	0
Post-Retirement Benefit Plans | U.S. stocks | Level 3
Employee Benefits
Fair value of plan assets		0		0			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		0			0	[5]	0
Post-Retirement Benefit Plans | Non-U.S. stocks
Employee Benefits
Fair value of plan assets valued at NAV							0		0
Fair value of plan assets		33		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		33			12	[6]	33
Post-Retirement Benefit Plans | Non-U.S. stocks | Level 1
Employee Benefits
Fair value of plan assets		33		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		33			12	[6]	33
Post-Retirement Benefit Plans | Non-U.S. stocks | Level 2
Employee Benefits
Fair value of plan assets		0		0			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		0			0	[6]	0
Post-Retirement Benefit Plans | Non-U.S. stocks | Level 3
Employee Benefits
Fair value of plan assets		0		0			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		0			0	[6]	0
Post-Retirement Benefit Plans | Multi-asset strategies
Employee Benefits
Fair value of plan assets valued at NAV							0		0
Post-Retirement Benefit Plans | Emerging market stocks
Employee Benefits
Fair value of plan assets valued at NAV							0		0
Fair value of plan assets		6		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		6			4	[10]	6
Post-Retirement Benefit Plans | Emerging market stocks | Level 1
Employee Benefits
Fair value of plan assets		6		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		6			4	[10]	6
Post-Retirement Benefit Plans | Emerging market stocks | Level 2
Employee Benefits
Fair value of plan assets		0		0			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		0			0	[10]	0
Post-Retirement Benefit Plans | Emerging market stocks | Level 3
Employee Benefits
Fair value of plan assets		0		0			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		0			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		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		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		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		0			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		0			0	[9]	0
Post-Retirement Benefit Plans | Cash equivalents and short-term investment funds | Level 2
Employee Benefits
Fair value of plan assets		8		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		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		0			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		$ 0			$ 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)

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 (Detai

Share-based Compensation (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	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
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 Sh69

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 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)

Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	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)

Income Taxes (Details 2) - USD ($) $ in Millions	12 Months Ended
	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)

Segment Information (Details) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015USD ($)	Sep. 30, 2015USD ($)	Jun. 30, 2015USD ($)	Mar. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Sep. 30, 2014USD ($)	Jun. 30, 2014USD ($)	Mar. 31, 2014USD ($)	Dec. 31, 2015USD ($)segment	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)
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)

Segment Information (Details 2) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015USD ($)	Sep. 30, 2015USD ($)	Jun. 30, 2015USD ($)	Mar. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Sep. 30, 2014USD ($)	Jun. 30, 2014USD ($)	Mar. 31, 2014USD ($)	Dec. 31, 2015USD ($)category	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)
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)

Segment Information (Details 3) - 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
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 (Una76

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 Contingencies77

Commitments and Contingencies (Details)	Jul. 16, 2013USD ($)	Oct. 14, 2011plaintiff	Dec. 31, 2015USD ($)plaintiff	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)	Dec. 31, 2007USD ($)
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
2,016			85,000,000
2,017			78,000,000
2,018			76,000,000
2,019			62,000,000
2,020			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
2,016			301,000,000
2,017			289,000,000
2,018			268,000,000
2,019			235,000,000
2,020			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
2,016			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 Oth

Other Financial Information Other Financial Information (Details) - USD ($) $ in Millions	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)

Labor Union Contracts (Details)	12 Months Ended
	Dec. 31, 2015Employee
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 Com80

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 Comprehensi81

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)

Accumulated Other Comprehensi82

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

Dividends (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