Frontier Communications Parent (FYBR) 10-K 1 Mar 18 2017 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Feb. 10, 2018	Jun. 30, 2017
Document and Entity Information [Abstract]
Entity Registrant Name	FRONTIER COMMUNICATIONS CORP
Entity Central Index Key	20,520
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$ 1,358,686
Entity Common Stock, Shares Outstanding		78,408,000
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	FY
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2017
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	Yes

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 362	$ 522
Accounts receivable, less allowances of $69 and $131, respectively	819	938
Prepaid expenses	78	88
Income taxes and other current assets	64	108
Total current assets	1,323	1,656
Property, plant and equipment, net	14,377	14,902
Goodwill, net	7,024	9,674
Other intangibles, net	2,063	2,662
Other assets	97	119
Total assets	24,884	29,013
Current liabilities:
Long-term debt due within one year	656	363
Accounts payable	564	698
Advanced billings	270	301
Accrued content costs	102	164
Accrued other taxes	156	134
Accrued interest	401	437
Pension and other postretirement benefits	29	23
Other current liabilities	330	324
Total current liabilities	2,508	2,444
Deferred income taxes	1,139	2,516
Pension and other postretirement benefits	1,676	1,602
Other liabilities	317	372
Long-term debt	16,970	17,560
Equity:
Preferred stock, $0.01 par value (50,000 authorized shares, 11.125%, Series A, 19,250 shares issued and outstanding)
Common stock, $0.25 par value (175,000 authorized shares, 79,532 issued, and 78,441 and 78,170 outstanding, at December 31, 2017 and 2016, respectively)	20	20
Additional paid-in capital	5,034	5,561
Accumulated deficit	(2,263)	(460)
Accumulated other comprehensive loss, net of tax	(366)	(387)
Treasury common stock	(151)	(215)
Total equity	2,274	4,519
Total liabilities and equity	$ 24,884	$ 29,013

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Consolidated Balance Sheets [Abstract]
Allowances for accounts receivable, current	$ 69	$ 131
Preferred Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Preferred Stock, Shares Authorized	50,000,000	50,000,000
Preferred Stock, Dividend Rate, Percentage	11.125%	11.125%
Preferred Stock, Shares Issued	19,250,000	19,250,000
Preferred Stock, Shares Outstanding	19,250,000	19,250,000
Common stock, par value (in dollars per share)	$ 0.25	$ 0.25
Common stock, shares authorized (in shares)	175,000,000	175,000,000
Common stock, shares outstanding (in shares)	78,441,000	78,170,000
Common stock, shares issued (in shares)	79,532,000	79,532,000

Consolidated Statements Of Oper

Consolidated Statements Of Operations - USD ($) shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Consolidated Statements Of Operations [Abstract]
Revenue	$ 9,128	$ 8,896	$ 5,576
Operating expenses:
Network access expenses	1,597	1,470	640
Network related expenses	1,959	1,887	1,287
Selling, general and administrative expenses	2,018	2,093	1,346
Depreciation and amortization	2,184	2,031	1,320
Goodwill impairment	2,748
Acquisition and integration costs	25	436	236
Pension settlement costs	83
Restructuring costs and other charges	82	91	2
Total operating expenses	10,696	8,008	4,831
Operating income (loss)	(1,568)	888	745
Investment and other income, net	3	27	7
Loss on early extinguishment of debt and debt exchanges	88	7
Interest expense	1,534	1,531	1,113
Loss before income taxes	(3,187)	(623)	(361)
Income tax benefit	(1,383)	(250)	(165)
Net loss	(1,804)	(373)	(196)
Less: Dividends on preferred stock	214	214	120
Net loss attributable to Frontier common shareholders	$ (2,018)	$ (587)	$ (316)
Basic net loss per share attributable to common shareholders of Frontier (in dollars per share)	$ (25.99)	$ (7.61)	$ (4.41)
Diluted net loss per share attributable to Frontier common shareholders	$ (25.99)	$ (7.61)	$ (4.41)
Total weighted average shares outstanding - basic	77,736	77,607	72,308
Total weighted average shares outstanding - diluted	77,736	77,607	72,308

Consolidated Statements Of Comp

Consolidated Statements Of Comprehensive Loss - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Consolidated Statements Of Comprehensive Loss [Abstract]
Net loss	$ (1,804)	$ (373)	$ (196)
Other comprehensive income (loss), net of tax	21	(34)	51
Comprehensive loss	$ (1,783)	$ (407)	$ (145)

Consolidated Statements Of Equi

Consolidated Statements Of Equity - USD ($) $ in Millions	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings (Accumulated Deficit) [Member]	Accumulated Other Comprehensive Loss [Member]	Treasury Common Stock [Member]	Total
Balance, beginning at Dec. 31, 2014		$ 17	$ 4,230	$ 109	$ (404)	$ (294)	$ 3,658
Balance (in shares) at Dec. 31, 2014		68,532,000				(1,701,000)
Issuance of stock (in shares)	19,250,000	11,000,000
Issuance of common stock		$ 3	796				799
Issuance of preferred stock			1,866				1,866
Stock plans			(4)			$ 16	12
Stock plans (in shares)						49,000
Dividends on common stock			(456)				(456)
Dividends on preferred stock			(120)				(120)
Net loss				(196)			(196)
Other comprehensive income (loss), net of tax					51		51
Preferred Stock Balance (in shares) at Dec. 31, 2015	19,250,000
Balance, ending at Dec. 31, 2015		$ 20	6,312	(87)	(353)	$ (278)	5,614
Balance (in shares) at Dec. 31, 2015		79,532,000				(1,652,000)
Stock plans			(44)			$ 63	19
Stock plans (in shares)						290,000
Dividends on common stock			(493)				(493)
Dividends on preferred stock			(214)				(214)
Net loss				(373)			(373)
Other comprehensive income (loss), net of tax					(34)		$ (34)
Preferred Stock Balance (in shares) at Dec. 31, 2016	19,250,000						19,250,000
Balance, ending at Dec. 31, 2016		$ 20	5,561	(460)	(387)	$ (215)	$ 4,519
Balance (in shares) at Dec. 31, 2016		79,532,000				(1,362,000)	78,170,000
Cumulative-effect adjustment from adoption of ASU 2016-09				1			$ 1
Stock plans			(47)			$ 64	17
Stock plans (in shares)						271,000
Dividends on common stock			(266)				(266)
Dividends on preferred stock			(214)				(214)
Net loss				(1,804)			(1,804)
Other comprehensive income (loss), net of tax					21		$ 21
Preferred Stock Balance (in shares) at Dec. 31, 2017	19,250,000						19,250,000
Balance, ending at Dec. 31, 2017		$ 20	$ 5,034	$ (2,263)	$ (366)	$ (151)	$ 2,274
Balance (in shares) at Dec. 31, 2017		79,532,000				(1,091,000)	78,441,000

Consolidated Statements Of Cash

Consolidated Statements Of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash flows provided from (used by) operating activities:
Net loss	$ (1,804)	$ (373)	$ (196)
Adjustments to reconcile net loss to net cash provided from operating activities:
Depreciation and amortization	2,184	2,031	1,320
Loss on early extinguishment of debt and debt exchanges	88	7
Pension settlement costs	83
Pension/OPEB costs	17	79	10
Special Termination Benefits	5	26
Stock based compensation expense	14	24	27
Amortization of deferred financing costs	33	46	191
Other adjustments	(14)	(12)
Deferred income taxes	(1,385)	(206)	(167)
Goodwill impairment	2,748
Change in accounts receivable	122	(19)	62
Change in accounts payable and other liabilities	(315)	(12)	116
Change in prepaid expenses, income taxes and other current assets	74	85	(48)
Net cash provided from operating activities	1,850	1,676	1,315
Cash flows provided from (used by) investing activities:
Cash paid for CTF acquisition		(9,871)
Capital expenditures - Business operations	(1,154)	(1,259)	(710)
Capital expenditures - Integration activities	(34)	(142)	(153)
Network expansion funded by Connect America Fund - Phase I			(22)
Proceeds on sale of assets	110	8	22
Cash paid for an acquisition, net of cash acquired			(17)
Other	24	5	2
Net cash used by investing activities	(1,054)	(11,259)	(878)
Cash flows provided from (used by) financing activities:
Long-term debt payments	(1,811)	(453)	(298)
Proceeds from long-term debt borrowings	1,500	1,940	6,603
Financing costs paid	(15)	(39)	(119)
Proceeds from issuance of common stock, net			799
Proceeds from issuance of preferred stock, net			1,866
Dividends paid on common stock	(266)	(493)	(456)
Dividends paid on preferred stock	(214)	(214)	(120)
Premium paid to retire debt	(86)
Capital lease obligation payments	(42)	(8)
Other	(8)	(8)	(14)
Net cash provided from (used by) financing activities	(942)	725	8,261
Increase/(Decrease) in cash, cash equivalents and restricted cash	(146)	(8,858)	8,698
Cash, cash equivalents and restricted cash at January 1,	522	9,380	682
Cash, cash equivalents and restricted cash at December 31,	376	522	9,380
Cash paid (received) during the period for:
Interest	1,548	1,467	728
Income taxes(refunds), net	(51)	(120)	28
Non-cash investing and financing activities:
Financing obligation for contribution of real property to pension plan		15
Reduction of pension obligation		15
Increase (decrease) in capital expenditures due to change in accounts payable	50	(60)	$ (56)
Capital lease obligations	$ 17	$ 111

Description Of Business And Sum

Description Of Business And Summary Of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2017
Description Of Business And Summary Of Significant Accounting Policies [Abstract]
Description of Business and Summary of Significant Accounting Policies	(1) Description of Business and Summary of Significant Accounting Policies : (a) Description of Business : Frontier Communications Corporation (Frontier) is the fourth largest Incumbent Local Exchange Carrier (ILEC) in the United States, with approximately 4.9 million customers, 3.9 million broadband subscribers and 22,700 employees, operating in 29 states. Frontier was incorporated in 1935, originally under the name of Citizens Utilities Company and was known as Citizens Communications Company until July 31, 2008. Frontier and its subsidiaries are referred to as “we,” “us,” “our,” “Frontier,” or the “Company” in this report.  Effective April 1, 2016, Frontier’s scope of operations and balance sheet changed materially as a result of the completion of the CTF Acquisition, as described in Note 3 - Acquisitions. Historical financial data presented for Frontier is not indicative of the future financial position or operating results for Frontier, and includes the results of the CTF Operations, as defined in Note 3 – Acquisitions, from the date of acquisition on April 1, 2016.  (b) Basis of Presentation and Use of Estimates : Our consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (GAAP). Certain reclassifications of amounts previously reported have been made to conform to the current presentation. All significant intercompany balances and transactions have been eliminated in consolidation.  For our financial statements as of and for the period ended December 31, 2017, we evaluated subsequent events and transactions for potential recognition or disclosure through the date that we filed this Form 10-K with the Securities and Exchange Commission (SEC).  The preparation of our financial statements in conformity with GAAP requires management to make estimates and assumptions that affect (i) the reported amounts of assets and liabilities at the date of the financial statements, (ii) the disclosure of contingent assets and liabilities, and (iii) the reported amounts of revenue and expenses during the reporting period. Actual results may differ from those estimates. Estimates and judgments are used when accounting for the allowance for doubtful accounts, asset impairments, indefinite-lived intangibles, depreciation and amortization, income taxes, business combinations, and pension and other postretirement benefits, among others.  On July 10, 2017, we effected a one for fifteen reverse stock split of our common stock. The reverse stock split reduced the number of common shares issued (which includes outstanding shares and treasury shares) from approximately 1,193,000,000 shares to 80,000,000 shares, and reduced shares outstanding from 1,178,000,000 shares to 79,000,000 shares. In addition, and at the same time, the total number of shares of common stock that Frontier is authorized to issue changed from 1,750,000,000 shares to 175,000,000 shares. There was no change in the par value of the common stock, and no fractional shares were issued. All share and per share amounts in the financial statements and footnotes have been retroactively adjusted for all periods presented to give effect to the reverse stock split. As a result of our reverse stock split the conversion rates of our Series A Preferred Stock were proportionately adjusted.  (c) Cash Equivalents : We consider all highly liquid investments with an original maturity of three months or less to be cash equivalents. Restricted cash of $14 million is included within “Income taxes and other current assets” on our consolidated balance sheet as of December 31, 2017. This amount represents funds held as collateral by certain insurance carriers, of which $7 million was released in January 2018, and the remainder expected to be released in the first quarter of 2018.  (d) Revenue Recognition : Revenue is recognized when services are provided or when products are delivered to customers. Revenue that is billed in advance includes monthly recurring network access services (including data services), special access services and monthly recurring voice, video and related charges. The unearned portion of these fees is initially deferred as a component of “Advanced billings” on our consolidated balance sheet and recognized as revenue over the period that the services are provided. Revenue that is billed in arrears includes non-recurring network access services (including data services), switched access services and non-recurring voice and video services. The earned but unbilled portion of these fees is recognized as revenue in our consolidated statements of operations and accrued in “Accounts Receivable” on our consolidated balance sheet in the period that the services are provided. Excise taxes are recognized as a liability when billed. Installation fees and their related direct and incremental costs are initially deferred and recognized as revenue and expense over the average term of a customer relationship. We recognize as current period expense the portion of installation costs that exceeds installation fee revenue.  Frontier collects various taxes from its customers and subsequently remits these taxes to governmental authorities. Substantially all of these taxes are recorded through the consolidated balance sheet and presented on a net basis in our consolidated statements of operations. We also collect Universal Service Fund (USF) surcharges from customers (primarily federal USF) that we have recorded on a gross basis in our consolidated statements of operations and included within “Revenue” and “Network related expenses” of $216 million, $217 million and $151 million for the years ended December 31, 2017, 2016 and 2015, respectively .  In 2015 we accepted the FCC’s Connect America Fund (CAF) Phase II offer of support, which is a successor to and augments the USF frozen high cost support that we had been receiving pursuant to a 2011 FCC order. Upon completion of the CTF Acquisition, Frontier assumed the CAF Phase II support and related obligations that Verizon had previously accepted with regard to California and Texas. CAF Phase II funding is a program intended to subsidize the high cost of establishing and delivering communications services to certain unserved or underserved areas. We are recognizing these subsidies into revenue on a straight line basis, which is consistent with how the costs related to these subsidies are being and are expected to be incurred. CAF Phase II is a multi-year program which requires us to deploy broadband to a specified number of households in each of the states where funding was accepted. Failure to meet our deployment obligations at the end of the program in 2020 will result in a return of a portion of the funding received. We regularly evaluate our ability to meet our broadband deployment obligations and adjust revenue accordingly.  We categorize our products, services and other revenues among the following five categories:   · Data and Internet services include broadband services for consumer and commercial customers. We provide data transmission services to high volume commercial customers and other carriers with dedicated high capacity circuits (“nonswitched access”) including services to wireless providers (“wireless backhaul”);   · Voice services include traditional local and long-distance wireline services, Voice over Internet Protocol (VoIP) services, as well as a number of unified messaging services offered to our consumer and commercial customers. Voice services also include the long-distance voice origination and termination services that we provide to our commercial customers and other carriers;   · Video services include revenues generated from services provided directly to consumer customers through the FiOS ® and Vantage video brands, and through DISH ® satellite TV services;   · Other customer revenue includes sales of customer premise equipment to our commercial customers and directory services, less our provision for bad debts; and   · Switched Access and Subsidy revenues include revenues derived from allowing other carriers to use our network to originate and/or terminate their local and long-distance voice traffic (“switched access”). These services are primarily billed on a minutes-of-use basis applying tariffed rates filed with the FCC or state agencies. We also receive cost subsidies from state and federal authorities, including the Connect America Fund Phase II.  The following table provides a summary of revenues from external customers by the categories of Frontier’s products and services:     For the year ended December 31,  ( $ in millions ) 2017 2016 2015   Data and Internet services $ 3,862 $ 3,693 $ 2,337  Voice services 2,864 2,886 2,022  Video services 1,304 1,244 285  Other 322 276 255  Customer revenue 8,352 8,099 4,899  Switched access and subsidy 776 797 677  Total revenue $ 9,128 $ 8,896 $ 5,576    (e) Property, Plant and Equipment : Property, plant and equipment are stated at original cost, including capitalized interest, or fair market value as of the date of acquisition for acquired properties. Maintenance and repairs are charged to operating expenses as incurred. The gross book value of routine property, plant and equipment retirements is charged against accumulated depreciation.  (f) Goodwill and Other Intangibles : Goodwill represents the excess of purchase price over the fair value of identifiable tangible and intangible net assets acquired. We undertake studies to determine the fair values of assets and liabilities acquired and allocate purchase prices to assets and liabilities, including property, plant and equipment, goodwill and other identifiable intangibles. We examine the carrying value of our goodwill and trade name annually as of December 31, or more frequently, as circumstances warrant, to determine whether there are any impairment losses. We test for goodwill impairment at the “operating segment” level, as that term is defined in GAAP.  We determined that we have one operating segment based on a number of factors that our management uses to evaluate and run our business operations, including similarities of customers, products and technology. We tested goodwill for impairment as of December 31, 2017 as a result of the continued decline in share price of our common stock since September 30, 2017, the date of our last goodwill impairment test. Refer to Note 6 for a discussion of our goodwill impairment testing and results as of December 31, 2017. As stated in Note 2, we early adopted ASU No. 2017-04, “Simplifying the Test for Goodwill Impairment” during 2017 in conjunction with our goodwill impairment assessment.  Frontier amortizes finite-lived intangible assets over their estimated useful lives on the accelerated method of sum of the years digits. We review such intangible assets at least annually as of December 31 to assess whether any potential impairment exists and whether factors exist that would necessitate a change in useful life and a different amortization period.  (g) Impairment of Long-Lived Assets and Long-Lived Assets to Be Disposed Of : We review long-lived assets to be held and used, including customer lists, and long-lived assets to be disposed of for impairment whenever events or changes in circumstances indicate that the carrying amount of such assets may not be recoverable. Recoverability of assets to be held and used is measured by comparing the carrying amount of the asset to the future undiscounted net cash flows expected to be generated by the asset. Recoverability of assets held for sale is measured by comparing the carrying amount of the assets to their estimated fair market value. If any assets are considered to be impaired, the impairment is measured by the amount by which the carrying amount of the assets exceeds the estimated fair value. Also, we periodically reassess the useful lives of our tangible and intangible assets to determine whether any changes are required. (h) Income Taxes and Deferred Income Taxes : We file a consolidated federal income tax return. We utilize the asset and liability method of accounting for income taxes. Under the asset and liability method, deferred income taxes are recorded for the tax effect of temporary differences between the financial statement basis and the tax basis of assets and liabilities using tax rates expected to be in effect when the temporary differences are expected to reverse.  (i) Stock Plans : We have various stock-based compensation plans. Awards under these plans are granted to eligible employees and directors. Awards may be made in the form of incentive stock options, non-qualified stock options, stock appreciation rights, restricted stock, restricted stock units or other stock-based awards, including awards with performance, market and time-vesting conditions. Our general policy is to issue shares from treasury upon the grant of restricted shares, earning of performance shares and the exercise of options.  The compensation cost recognized is based on awards ultimately expected to vest. GAAP requires forfeitures to be estimated and revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates.  (j) Net Loss Per Share Attributable to Frontier Common Shareholders : Basic net loss per common share is computed using the weighted average number of common shares outstanding during the period being reported on, excluding unvested restricted stock awards. The impact of dividends paid on unvested restricted stock awards have been deducted in the determination of basic and diluted net income (loss) per share attributable to Frontier common shareholders. Except when the effect would be antidilutive, diluted net income per common share reflects the dilutive effect of certain common stock equivalents, as described further in Note 13 – Net Loss Per Common Share. 

Recent Accounting Pronouncement

Recent Accounting Pronouncements	12 Months Ended
	Dec. 31, 2017
Recent Accounting Pronouncements [Abstract]
Recent Accounting Pronouncements	(2 ) Recent Accounting Pronouncements :  Recent Accounting Pronouncements Not Yet Adopted  Revenue Recognition In May 2014, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2014-09, “Revenue from Contracts with Customers.” This standard, along with its related amendments, requires companies to recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which they expect to be entitled in exchange for those goods or services. This new standard will be adopted by Frontier for annual and interim reporting periods beginning with the first quarter of 2018.  The FASB allows two adoption methods under ASC 606. Companies are permitted to either apply the requirements retrospectively to all prior periods presented, or apply the requirements in the year of adoption, through a cumulative adjustment. We currently plan to adopt the standard in the first quarter of 2018, using the “modified retrospective method.” Under that method, we will apply the rules to all contracts existing as of January 1, 2018, recognizing, in beginning retained earnings, a cumulative-effect adjustment to include the establishment of contract asset and contract liability accounts with a corresponding adjustment to retained earnings. We will also provide additional disclosures comparing revenue recognized under ASC 606 to revenue as reported prior to the adoption of the standard.  The key changes in the standard that impact our revenue recognition relate to the allocation of contract revenues among various services and equipment, and the timing of when those revenues are recognized. Additionally, the new standard will impact the timing of recognizing costs to obtain contracts. This includes a change in our existing policy related to the way we account for the allocation of discounts, customer incentives, upfront non-recurring charges, customer disputes and commission payments.  We are implementing changes to our systems, processes, policies and internal controls to meet the standard’s reporting and disclosure requirements. We believe the changes will impact service revenue categorization as well as Selling, general and administrative expenses, however, we do not anticipate its impact will be material to operating income.  Leases In February 2016, the FASB issued ASU No. 2016 – 02, “Leases (Topic 842).” This standard, along with its related amendments, establishes the principles to report transparent and economically neutral information about the assets and liabilities that arise from leases. Upon implementation, l essees will need to recognize almost all leases on their balance sheet as a right-of-use asset and a lease liability. It will be critical to identify leases embedded in a contract to avoid misstating the lessee’s balance sheet. The income statement impacts of the leases will depend on the nature of the leasing arrangement and will be similar to existing accounting for operating and capital leases. Classification will be based on criteria that are largely similar to those applied in current lease accounting, but without explicit bright lines. Lessor accounting is similar to the current model, but updated to align with certain changes to the lessee model and the new revenue recognition standard. Existing sale-leaseback guidance, including guidance for real estate, is replaced with a new model applicable to both lessees and lessors. The new guidance is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years using modified retrospective application. Early application is permitted . Frontier is in the initial stages of evaluating the potential impact this new standard may have on the consolidated financial statements.  Compensation – Retirement Benefits In March 2017, the FASB issued ASU No. 2017-07, “Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost”. This standard was established to improve the presentation of net periodic pension cost and net periodic postretirement benefit cost by requiring that an employer disaggregate the service cost component of periodic benefit cost from the other components of net benefit cost. The amendments in the update also provide explicit guidance on how to present the service cost component and other components of net benefit cost in the income statement and allow only the service cost components of net benefit cost to be eligible for capitalization. The new guidance is effective for annual periods beginning after December 15, 2017, including interim periods within those annual periods and requires the presentation of the income statement to be applied retrospectively. As a result of the standard, pension settlement costs and certain benefit costs which are currently included in operating expense, would be reported as other non-operating expense and will no longer be capitalized. This will have a material impact on previously reported operating income and may have a material impact to operating income in future periods, however, the impact to pre-tax income is not expected to be material.  Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income In February 2018, FASB issued ASU 2018-02, which allows for the reclassification of certain income tax effects related to the Tax Cuts and Jobs Act (the “Tax Act”) between “Accumulated other comprehensive income” and “Retained earnings.” This ASU relates to the requirement that adjustments to deferred tax liabilities and assets related to a change in tax laws or rates to be included in “Income from continuing operations”, even in situations where the related items were originally recognized in “Other comprehensive income” (rather than in “Income from continuing operations”). The amendments in this ASU are effective for all entities for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years, with early adoption permitted. Adoption of this ASU is to be applied either in the period of adoption or retrospectively to each period in which the effect of the change in the tax laws or rates were recognized. We are still evaluating certain aspects of this ASU as well as the related impacts it may have on our financial statements.   Recently Adopted Accounting Pronouncements  Share-Based Payments - Scope of Modification Accounting In May 2017, the FASB issued ASU No. 2017-09, Scope of Modification Accounting which amends the scope of modification accounting for share-based payment arrangements. This standard provides guidance on the types of changes to the terms or conditions of share-based payment awards to which an entity would be required to apply modification accounting under ASC 718. Specifically, an entity would not apply modification accounting if the fair value, vesting conditions, and classification of the awards are the same immediately before and after the modification. The new guidance is effective for annual periods beginning after December 15, 2017, including interim periods within those annual periods and early adoption is permitted including in any interim period. Frontier has adopted this standard during the second quarter 2017, with no impact to our share-based payment awards.  Intangibles – Goodwill In January 2017, the FASB issued ASU No. 2017-04, “Simplifying the Test for Goodwill Impairment.” This standard was established to simplify how an entity is required to test goodwill for impairment by eliminating Step 2 from the goodwill impairment test. Step 2 measures a goodwill impairment loss by comparing the implied fair value of a reporting unit’s goodwill with the carrying amount of that goodwill. Under the amendments in this Update, an entity should perform its annual, or interim, goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount. An entity should recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value; however, the loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. Additionally, an entity should consider income tax effects from any tax deductible goodwill on the carrying amount of the reporting unit when measuring the goodwill impairment loss, if applicable. The FASB also eliminated the requirements for any reporting unit with a zero or negative carrying amount to perform a qualitative assessment and, if it fails that qualitative test, to perform Step 2 of the goodwill impairment test. Therefore, the same impairment assessment applies to all reporting units. An entity is required to disclose the amount of goodwill allocated to each reporting unit with a zero or negative carrying amount of net assets. An entity still has the option to perform the qualitative assessment for a reporting unit to determine if the quantitative impairment test is necessary. Frontier early adopted this standard during in 2017 in conjunction with our goodwill impairment assessment. See Note 1 and Note 6 for further discussion.  Compensation – Stock Compensation In March 2016, the FASB issued ASU No. 2016-09, “Improvements to Employee Share-Based Payment Accounting,” to amend ASC Topic 718, “Compensation – Stock Compensation.” The ASU is part of the FASB’s ongoing simplification initiative, which is designed to reduce cost and complexity while maintaining or improving the usefulness of the information provided to the users of financial statements. The simplifications address a variety of areas for public entities, including the following: 1) accounting for income taxes, 2) classification of excess tax benefits on the statement of cash flows, 3) forfeitures, 4) minimum statutory tax withholding requirements, 5) classifications of employee taxes paid on the statement of cash flows when an employer withholds shares for tax withholding purposes, and 6) classification of awards with repurchase features. This guidance was effective for Frontier as of the third quarter of 2017. During the year ended December 31, 2017 Frontier recognized $1 million of income tax expense and recorded a cumulative effect adjustment to beginning accumulated deficit of $1 million to recognize all unrecognized deferred tax benefits recorded as of January 1, 2017. For the years ended December 31, 2016 and 2015, Frontier reclassified $10 million and $14 million, respectively, of taxes paid on behalf of employees related to shares withheld from “Cash flows provided from (used by) operations” to “Cash flows used by financing activities” in accordance with the new standard. 

Acquisitions

Acquisitions	12 Months Ended
	Dec. 31, 2017
Acquisitions [Abstract]
Acquisitions	(3) Acquisitions :  The CTF Acquisition On April 1, 2016, Frontier acquired the wireline operations of Verizon Communications, Inc. in California, Texas and Florida for a purchase price of $ 10,540 million in cash and assumed debt (the CTF Acquisition), pursuant to the February 5, 2015 Securities Purchase Agreement, as amen ded. In addition, Frontier and Verizon settled the working capital and net debt adjustments with $ 15 million paid to Frontier in October 2016. As a result of the CTF Acquisition, Frontier now operates these former Verizon properties, which included approximately 2.5 million total customers, 2.1 million broadband subscribers, and 1.2 million FiOS video subscribers as of April 1, 2016 (the CTF Operations).  Our consolidated statement of operations for the year ended December 31, 2016 includes $3,622 million of revenue and $582 million of operating income related to the nine months of operating results of the CTF Operations since April 1, 2016.  The allocation of the purchase price presented below, which was finalized as of March 31, 2017, represents the effect of recording the estimates of the fair value of assets acquired and liabilities assumed as of the date of the CTF Acquisition, based on the total transaction cash consideration of $ 9,871 million at December 31, 201 7.      ($ in millions)   Current assets $ 353  Property, plant & equipment 6,096  Goodwill 2,606  Other intangibles - primarily customer base 2,262  Current liabilities (579)  Long-term debt (544)  Other liabilities (323)  Total net assets acquired $ 9,871   The fair value estimates related to the allocation of the purchase price to Other intangibles were revised and updated during the first quarter of 2017 from the previous estimates as of December 31, 2016. The allocation that was reported as of December 31, 2016 for Other intangibles increased $100 million, from $2,162 million to $2,262 million. These measurement period adjustments resulted in $20 million of amortization expense during the first quarter of 2017 that would have been recorded in 2016 if the adjustments had been recognized as of the acquisition date. Other adjustments to the allocation of the purchase price for the CTF Acquisition during the first quarter of 2017 resulted in a $140 million decrease in Property, plant & equipment, a $61 million increase in Current liabilities, and a $98 million increase in Goodwill.  The total consideration exceeded the net estimated fair value of the assets acquired and liabilities assumed by $2,606 million, which we recognized as goodwill. This goodwill is attributable to strategic benefits, including enhanced financial and operational scale, market diversification and leveraged combined networks that we expect to realize. This amount of goodwill associated with the CTF Acquisition will be dedu ctible for income tax purposes. The following unaudited pro forma financial information presents the combined results of operations of Frontier and the CTF Operations as if the CTF Acquisition had occurred as of January 1, 2015. The pro forma information is not necessarily indicative of what the financial position or results of operations actually would have been had the CTF Acquisition been completed as of January 1, 2015. In addition, the unaudited pro forma financial information is not indicative of, nor does it purport to project, the future financial position or operating results of Frontier. The unaudited pro forma financial information excludes acquisition and integration costs and does not give effect to any estimated and potential cost savings or other operating efficiencies that may result from the CTF Acquisition.      (Unaudited)  For the year ended December 31,  ($ in millions, except per share amounts) 2016 2015   Revenue $ 10,255 $ 11,157   Operating income $ 1,433 $ 1,529   Net loss attributable to Frontier  common shareholders $ (262) $ (192)   Basic and diluted net loss per  share attributable to Frontier  common shareholders $ (3.38) $ (2.66)    The Connecticut Acquisition On October 24, 2014, Frontier acquired the wireline properties of AT&T Inc. (AT&T) in Connecticut (the Connecticut Acquisition) for a purchase price of $2,018 million in cash, pursuant to the stock purchase agreement dated December 16, 2013, as amended. Following the Connecticut Acquisition, Frontier now owns and operates the wireline business and fiber optic network servicing consumer, commercial and wholesale customers in Connecticut. Frontier also acquired the AT&T U-verse ® video (Vantage) and DISH ® satellite TV customers in Connecticut.  Acquisition and Integration Costs Acquisition costs include legal, financial advisory, accounting, regulatory and other related costs. Integration costs include expenses that are incremental and directly related to the acquisition, and were incurred to integrate the network and information technology platforms and to enable other integration initiatives.  Frontier incurred operating expenses related to the CTF Acquisition and the Connecticut Acquisition, as follows:       For the year ended December 31,  ($ in millions) 2017 2016 2015   Acquisition costs:  CTF Acquisition $ - $ 23 $ 44  Connecticut Acquisition - - 1  - 23 45  Integration costs:  CTF Acquisition 25 412 152  Connecticut Acquisition - 1 39  25 413 191  Total acquisition and  integration costs $ 25 $ 436 $ 236   We also invested $34 million , $142 million, and $129 mi llion in capital expenditures related to the CTF Acquisition during the years ended December 31, 201 7, 201 6, and 2015 , respectively. In connection with the Connecticut Acquisition, Frontier invested $24 million in capital expenditures during the year ended December 31, 201 5.

Accounts Receivable

Accounts Receivable	12 Months Ended
	Dec. 31, 2017
Accounts Receivable [Abstract]
Accounts Receivable	( 4 ) Accounts Receivable : The components of accounts receivable, net at December 31, 201 7 and 201 6 are as follows :       ($ in millions) 2017 2016   Retail and Wholesale $ 801 $ 979  Other 87 90  Less: Allowance for doubtful accounts (69) (131)  Accounts receivable, net $ 819 $ 938   An analysis of the activity in the allowance for doubtful accoun ts for the years ended December 31, 201 7 , 201 6 and 201 5 is as follows:      ( $ in millions ) Balance at beginning of Period Charged to Other Revenue Charged (Credited) to Switched and Nonswitched Revenue and Other Accounts Write-offs, net of Recoveries Balance at end of Period   2015 $ 72 $ 67 $ (17) $ (65) $ 57  2016 $ 57 $ 164 $ 15 $ (105) $ 131  2017 $ 131 $ 109 $ (22) $ (149) $ 69   We maintain an allowance for doubtful accounts based on our estimate of our ability to collect accounts receivable. The provisio n for uncollectible amounts was $87 million, $179 million , and $50 million for the years ended December 31, 201 7 , 201 6 and 201 5 , respectively. Our allowance for doubtful accounts increased in 2016 primarily as a result of the customer account balances related to CTF Operations subsequent to the CTF Acquisition. Our allowance for doubtful accounts decreased during 2017 primarily as a result of resolutions of carrier disputes and increased collection efforts on delinquent balances in both our CTF and Legacy markets. Resolutions reached with carriers resulted in a reduction of our reserves of $39 million in 2017.

Property, Plant And Equipment

Property, Plant And Equipment	12 Months Ended
	Dec. 31, 2017
Property, Plant And Equipment [Abstract]
Property, Plant And Equipment	(5) Property, Plant and Equipment : Property, plant and equipment, net at December 31, 201 7 and 201 6 are as follows :       ($ in millions) Estimated Useful Lives 2017 2016   Land N/A $ 231 $ 235  Buildings and leasehold improvements 41 years 2,282 2,320  General support 5 to 17 years 1,570 1,502  Central office/electronic circuit equipment 5 to 18 years 8,137 7,683  Poles 30 years 1,095 995  Cable, fiber and wire 15 to 25 years 10,997 10,292  Conduit 55 years 1,646 1,611  Construction work in progress 538 903  Property, plant and equipment 26,496 25,541  Less: Accumulated depreciation (12,119) (10,639)  Property, plant and equipment, net $ 14,377 $ 14,902  Property, plant, and equipment includes approximately $171 million and $154 million of fixed assets recognized under capital leases as of December 31, 201 7 and 201 6 , respectively.  In 2017, we sold certain properties, generating $102 million in net proceeds, of which $97 million relates to property subject to leasebacks. For these properties, we have deferred $66 million in related gains that will be amortized over the related lease terms of two years. For year ended December 31, 2017, amortization of these deferred gains totaled $23 million, which are included in “Selling, general and administrative expenses” on our consolidated income statement. We have remaining deferred gain balances of $43 million, which are included in “Other liabilities . ”  Depreciation expense is principally based on the composite group method. Depreciation expense was as follows :       For the Year Ended  ($ in millions) 2017 2016 2015   Depreciation expense $ 1,485 $ 1,388 $ 983   We adopted new estimated remaining useful lives for certain plant assets as of October 1, 201 7 , as a result of an annual independent study of the estimated remaining useful lives of our plant assets, with an insignificant impact to depreciation expense.

Goodwill And Other Intangibles

Goodwill And Other Intangibles	12 Months Ended
	Dec. 31, 2017
Goodwill And Other Intangibles [Abstract]
Goodwill And Other Intangibles	(6) Goodwill and Other Intangibles : The changes in the carrying amount of goodwill, net for the years ended December 31, 2017 and 2016 were as follows :      ($ in millions) Goodwill   Balance at January 1, 2016 $ 7,166  CTF Acquisition (Note 3) 2,508  Balance at December 31, 2016 9,674  CTF Acquisition adjustment 98  Goodwill impairment (2,748)  Balance at December 31, 2017 $ 7,024   Accumulated goodwill impairment charges were $2,788 million and $40 million as of December 31, 2017 and 2016, respectively .  We are required to perform impairment tests related to our goodwill annually, which we perform as of December 31, or sooner if an indicator of impairment occurs. Due to the continued decline in our stock price we had triggering events in each of the four quarters in 2017.  We use a market multiples approach to determine fair value. Marketplace company comparisons and analyst reports within the wireline telecommunications industry have historically supported a range of fair values of multiples between 4.4x and 6.5x annualized EBITDA (defined as operating income, net of acquisition and integration costs, pension/OPEB expense, pension settlement costs, stock-based compensation expense, goodwill impairment, storm-related costs, and restructuring costs and other charges, as well as depreciation and amortization). We estimated the enterprise fair value using a multiple of 5.8x EBITDA for the first three quarters in 2017 and a multiple of 5.5x EBITDA for the fourth quarter evaluation.  Our second and fourth quarter quantitative assessments indicated that the carrying value of the enterprise exceeded its fair value and, therefore, an impairment existed. We elected to early adopt the simplified goodwill testing method under ASU 2017-04, recording goodwill impairments totaling $2,748 million for 2017. The driver for the impairment in the second quarter was a reduction in our profitability and utilized EBITDA estimate, which when applied to our market multiple resulted in a lower enterprise valuation. During the fourth quarter, the impairment was largely driven by a lower enterprise valuation resulting from a reduction in utilized market multiple from 5.8x to 5.5x reflecting the lower outlook for our industry as a whole. The revaluation of our net deferred tax liabilities which resulted from the enactment of Tax Cut and Job Act, caused further goodwill impairment (see Note 12).  Our first and third quarter quantitative assessments indicated that the fair value of the enterprise exceeded its carrying value and, therefore, no indication of impairment existed in either period.  The market multiples approach that we use incorporates significant estimates and assumptions related to the forecasted results for the remainder of the year including revenues, expenses, and the achievement of other cost synergies. Our assessment includes many qualitative factors that require significant judgment. Alternative interpretations of these factors could have resulted in different conclusions regarding the need for, or size of, an impairment. Continued declines in our profitability or cash flows or in the sustained, historically low trading prices of our common stock may result in further impairment.  We also considered whether the carrying values of finite-lived intangible assets and property plant and equipment may not be recoverable or whether the carrying value of certain indefinite-lived intangible assets were impaired, noting no additional impairment was present as of December 31, 2017.  The components of other intangibles at December 31, 201 7 and 201 6 are as follows :       2017 2016  ($ in millions) Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount   Other Intangibles:  Customer base $ 5,188 $ (3,294) $ 1,894 $ 5,088 $ (2,604) $ 2,484  Trade name 122 - 122 122 - 122  Royalty agreement 72 (25) 47 72 (16) 56  Total other intangibles $ 5,382 $ (3,319) $ 2,063 $ 5,282 $ (2,620) $ 2,662   Amortization expense was as follows :      For the Year Ended  ($ in millions) 2017 2016 2015   Amortization expense $ 699 $ 643 $ 337   Amortization expense primarily represents the am ortization of our customer base acquired as a result of the CTF Acquisition, the Connecticut Acquisition and the acquisition of certain Verizon properties in 2010 with each based on a useful life of 8 to 12 years on an accelerated method. The approximate weighted average remaining life of our customer base is 6 years and for our royalty agreement is 3 years. Amortization expense based on our current estimate of useful lives, is estimated to be approximately $569 million in 201 8 , $454 million in 201 9 , $354 million in 20 20 , $260 million in 202 1 , and $173 million in 202 2.

Long-Term Debt

Long-Term Debt	12 Months Ended
	Dec. 31, 2017
Long-Term Debt [Abstract]
Long-Term Debt	(7) Long-Term Debt : The activity in our long-term debt from January 1, 201 7 to December 31, 201 7 is summarized as follows :        Year ended December 31, 2017  ($ in millions) January 1, 2017 Payments and Retirements New Borrowings December 31, 2017 Interest Rate at December 31, 2017*   Senior & Subsidiary  Unsecured Debt $ 15,900 $ (1,655) $ - $ 14,245 9.22%  Senior Secured Debt 2,151 (155) 1,500 3,496 5.24%  Secured Subsidiary Debt 100 - - 100 8.50%  Secured Debt 19 (3) - 16 5.56%  Rural Utilities Service Loan Contracts 8 (1) - 7 6.15%  Total Debt $ 18,178 $ (1,814) $ 1,500 $ 17,863 8.44%   Less: Debt Issuance Costs (209) (183)  Less: Debt Premium (Discount) (46) (54)  Less: Current Portion (363) (656)  Total Long-Term Debt $ 17,560 $ 16,970   * Interest rate includes amortization of debt issuance costs and debt premiums or discounts. The interest rates at December 31, 2017 represent a weighted average of multiple issuances .   Additional information regarding our senior unsecured debt, senior secured debt and subsidiary debt at December 31, 201 7 and 201 6 is as follows:      2017 2016   Principal Interest Principal Interest  ($ in millions) Outstanding Rate Outstanding Rate   Senior Unsecured Debt Due:  4/15/2017 $ - 8.250% $ 210 8.250%  10/1/2018 491 8.125% 583 8.125%  3/15/2019 404 7.125% 434 7.125%  4/15/2020 619 8.500% 1,169 8.500%  9/15/2020 303 8.875% 1,066 8.875%  7/1/2021 490 9.250% 500 9.250%  9/15/2021 775 6.250% 775 6.250%  4/15/2022 500 8.750% 500 8.750%  9/15/2022 2,188 10.500% 2,188 10.500%  1/15/2023 850 7.125% 850 7.125%  4/15/2024 750 7.625% 750 7.625%  1/15/2025 775 6.875% 775 6.875%  9/15/2025 3,600 11.000% 3,600 11.000%  11/1/2025 138 7.000% 138 7.000%  8/15/2026 2 6.800% 2 6.800%  1/15/2027 346 7.875% 346 7.875%  8/15/2031 945 9.000% 945 9.000%  10/1/2034 1 7.680% 1 7.680%  7/1/2035 125 7.450% 125 7.450%  10/1/2046 193 7.050% 193 7.050%  13,495 15,150   Senior Secured Debt Due:  10/24/2019 (1) 245 5.445% (Variable) 280 4.145% (Variable)  3/31/2021 (2) 1,483 4.320% (Variable) 1,564 3.270% (Variable)  10/12/2021 (3) 276 5.445% (Variable) 307 4.145% (Variable)  6/15/2024 (4) 1,492 5.320% (Variable) -  3,496 2,151   Subsidiary Debentures Due:  5/15/2027 200 6.750% 200 6.750%  2/1/2028 300 6.860% 300 6.860%  2/15/2028 200 6.730% 200 6.730%  10/15/2029 50 8.400% 50 8.400%  11/15/2031 100 8.500% 100 8.500%  850 850   Total $ 17,841 8.1% (5) $ 18,151 8.3% (5)     (1) Represents borrowings under the 2014 CoBank Credit Agreement, as defined below. (2) Represents borrowings under the JPM Credit Agreement Term Loan A, as defined below. (3) Represents borrowings under the 2016 CoBank Credit Agreement, as defined below. (4) Represents borrowings under the JPM Credit Agreement Term Loan B, as defined below. (5) Interest rate represents a weighted average of the stated interest rates of multiple issuances .  New Notes Issuances Upon completion of the CTF Acquisition on April 1, 2016, we assumed additional debt of $600 million, including $200 million aggregate principal amount of 6.75% Senior Notes due May 15, 2027 , $300 million aggregate principal amount of 6.86% Senior Notes due February 1, 2028 and $100 million aggregate principal amount of 8.50% Senior Notes due November 15, 2031.  On September 25, 2015, Frontier completed a private offering of $6,600 million aggregate principal amount of unsecured Senior Notes, as follows: $1,000 million of 8.875% Senior Notes due 2020; $2,000 million of 10.50% Senior Notes due 2022; and $3,600 million of 11.00% Senior Notes due 2025 . Each was issued at a price equal to 100% of its principal amount. Frontier used the net proceeds from the offering (after deducting underwriting fees) to finance a portion of the cash consideration paid in connection with the CTF Acquisition and to pay related fees and expenses. The net proceeds of the debt offering of $6,485 million were included in “Restricted cash” in the consolidated balance sheet as of December 31, 2015. In June 2016, we completed an exchange offer of registered senior notes for the privately placed senior notes.  Debt Reductions and Conversions During 2017, Frontier used proceeds from Term Loan B (see definition and note discussion below) and cash on hand to retire $763 million of 8.875% Notes due 2020 , $550 million of 8.500% Notes due 2020 , $92 million of 8.125% Notes due 2018 , $30 million of 7.125% Notes due 2019 , and $10 million of 9.250% Notes due 2021 . Frontier recorded a loss of $88 million driven primarily by premiums on the retirement of the notes. Additionally, Frontier used cash available on hand for the scheduled retirement of $210 million of 8.25% Senior Notes at maturity.  During 2016, we completed non-cash debt exchanges including related accrued interest, of $397 million of our 8.25% Notes due April 2017 for approximately $147 million of our 8.50% Notes due April 2020, $66 million of our 8.875% Notes due September 2020, and $188 million of our 10.50% Notes due September 2022. A pretax loss of approximately $7 million was recognized and included in our consolidated statement of operations for the year ended December 31, 2016.  During 2015, Frontier used cash available on hand for the scheduled retirement of $97 million of 7.875% Senior Notes, and $105 million 6.625% Senior Notes at maturity.  Term Loans and Credit Facilities On February 27, 2017, Frontier entered into a first amended and restated credit agreement with JPMorgan Chase Bank, N.A., as administrative agent, and the lenders party thereto, pursuant to which Frontier combined its revolving credit agreement, dated as of June 2, 2014, and its term loan credit agreement, dated as of August 12, 2015. Under the JPM Credit Agreement, as further amended on June 15, 2017 by Increase Joinder No.1 (as so amended, the JPM Credit Agreement), Frontier has a $1,625 million senior secured term loan A facility (the Term Loan A) maturing on March 31, 2021 , an $850 million undrawn secured revolving credit facility maturing on February 27, 2022 (the Revolver), and $1,500 million senior secured term loan B facility (the Term Loan B) maturing on June 15, 2024 . The maturities of the Term Loan A, the Revolver, and the Term Loan B, in each case if still outstanding, will be accelerated in the following circumstances: (i) if, 91 days before the maturity date of any series of Senior Notes maturing in 2020, 2023 and 2024, more than $500 million in principal amount remains outstanding on such series; or (ii) if, 91 days before the maturity date of the first series of Senior Notes maturing in 2021 or 2022, more than $500 million in principal amount remains outstanding, in the aggregate, on the two series of Senior Notes maturing in such year. The determination of interest rates for each of the facilities under the JPM Credit Agreement is based on margins over the Base Rate (as defined in the JPM Credit Agreement) or over LIBOR, at the election of Frontier. Interest rate margins on the Term Loan A and Revolver (ranging from 0.75% to 1.75% for Base Rate borrowings and 1.75% to 2.75% for LIBOR borrowings) are subject to adjustment based on Frontier’s Total Leverage Ratio (as defined in the JPM Credit Agreement). The interest rate on the Term Loan A as of December 31, 2017 was LIBOR plus 2.75% . Interest rate margins on the Term Loan B ( 2.75% for Base Rate borrowings and 3.75% for LIBOR borrowings) are not subject to adjustment. The security package under the JPM Credit Agreement includes pledges of the equity interests in certain Frontier subsidiaries and guaranties by certain Frontier subsidiaries. As of December 31, 2017 no borrowing had been made under the revolving credit facility. Letters of credit, which may be issued under the revolver up to a maximum of $134 million, reduce available borrowing capacity under the revolving credit facility. Letters of credit issued under the revolver totaled $63 million and $0 as of December 31, 2017 and 2016, respectively. The revolving credit facility is available for general corporate purposes but may not be used to fund dividend payments if the undrawn amount under the revolver is less than $250 million.  Frontier has two senior secured credit agreements with CoBank, ACB, as administrative agent, lead arranger and a lender, and the other lenders party thereto: the first, drawn in 2011 (the 2011 CoBank Credit Agreement), was refinanced on October 12, 2016 with a similar facility for $315 million, maturing on October 12, 2021 (the 2016 CoBank Credit Agreement), and the second, drawn in 2014 (the 2014 CoBank Credit Agreement), matures on October 24, 2019 . Repayment of the principal balance will be made in quarterly installments of $8 million which commenced December 31, 2016 for the 2016 CoBank Credit Agreement, and $9 million which commenced on March 31, 2015 for the 2014 CoBank Credit Agreement. The remaining outstanding principal balances to be repaid on the maturity date.  On March 29, 2017, Frontier amended the 2014 and 2016 CoBank Credit Agreements. The amendments provide that interest rate margins under each of these facilities will range from 0.875% to 3.875% for Base Rate borrowings and 1.875% to 4.875% for LIBOR borrowings, subject to adjustment based on our Total Leverage Ratio, as defined in each credit agreement. The interest rate on each of the facilities as of December 31, 2017 was LIBOR plus 3.875% . In addition, the amendments provide for increases in the maximum Leverage Ratio and expansion of the security package identical to those contained in the JPM Credit Agreement.  On January 25, 2018 Frontier further amended its credit agreements with JP Morgan Chase and CoBank (JPM Credit Amendment). The amendments expanded the security package to include interests of certain subsidiaries previously not pledged and replaced the net leverage ratio maintenance test with a first lien net leverage ratio maintenance test.  During 2015, we entered into secured financings totaling $3 million with four year terms and no stated interest rate for certain equipment purchases.  As of December 31, 2017, we were in compliance with all of our debt and credit facility covenants.  Our scheduled principal payments are as follows as of December 31, 201 7 :       Principal  ($ in millions) Payments   2018 $ 656  2019 $ 804  2020 $ 1,132  2021 $ 2,558  2022 $ 2,703  Thereafter $ 10,010     Other Obligations During 201 6 , Frontier contributed a real estate property with a fair value of $15 million for the purpose of funding a portion of its contribution obligations to its qualified defined benefit pension plan. The pension plan obtained independent appraisals of the property and, based on these appraisals, the pension plan recorded the contribution at its fair value of $15 million. Frontier has entered into a lease for the contributed property with initial terms of 15 years at a combined aggregate annual rent of approximately $2 million. The property is managed on behalf of the pension plan by an independent fiduciary, and the terms of the lease were negotiated with the fiduciary on an arm’s-length basis.  The contribution and leaseback of the property was treated as a financing transaction and, accordingly, Frontier continues to depreciate the carrying value of the property in its financial statements and no gain or loss was recognized. An obligation of $15 million was recorded in our consolidated balance sheet within “Other liabilities” and the liability is reduced annually by a portion of the lease payments made to the pension plan.  During 2017 and 201 6 , Frontier modified certain o perating leases for vehicles which resulted in the classification as capital leases. These agreements have lease terms of 1 to 7 years. These capital lease obligations are included in our consolidated balance sheet within “Other liabilities” and “Other current liabilities . ”  In 2012, Frontier entered into a sale and leaseback arrangement for a facility in Everett, Washington and entered into a capital lease for the use of fiber in the state of Minnesota. These agreements have lease terms of 12 and 23 years, respectively. These capital lease obligations are included in our consolidated balance sheet within “Other liabilities” and “Other current liabilities.”  Future minimum payments for finance lease obligations and capital lease obligations as of December 31, 201 7 are as follows:       ($ in millions) Finance Lease Obligations Capital Lease Obligations   Year ending December 31:  2018 $ 9 $ 41  2019 9 29  2020 10 19  2021 10 12  2022 10 9  Thereafter 52 9  Total future payments 100 119  Less: Amounts representing interest (55) (14)  Present value of minimum lease payments $ 45 $ 105  

Restructuring Costs

Restructuring Costs	12 Months Ended
	Dec. 31, 2017
Restructuring Costs [Abstract]
Restructuring Costs	 (8) Restructuring Costs As of December 31, 201 7 , restructuring related liabilities of $25 million pertaining to employee separation charges are included in “Other current liabilities” in our consolidated balance sheet.  During 2017, restructuring costs and other charges, primarily consisting of severance and other employee-related costs of $68 million, pension/OPEB benefit enhancements of $5 million and the loss recorded on the sale of Frontier’s Secure Strategic Partnerships business of $9 million, totaling $82 million in connection with workforce reductions, are included in “Restructuring costs and other charges” in our consolidated statement of operations for the year ended December 31, 2017.  During 201 6 , restructuring costs and other charges, primarily consisting of severance an d other employee-related costs of $65 million, and pension/OPEB benefit enhancements of $26 million, totaling $91 million in connection with workforce reductions, are included in “ Restructuring costs and other charges” in our consolidated statement of operations for the year ended December 31, 2016 .  The following is a summary of the changes in the liabilities established for restru cturing programs at December 31 , 201 7 :       Restructuring  ($ in millions) Liability  Balance, January 1, 2016 $ 1  Severance costs 65  Cash payments during the period (19)  Balance, December 31, 2016 47  Severance costs 68  Cash payments during the period (90)  Balance, December 31, 2017 $ 25  

Investment and Other Income, Ne

Investment and Other Income, Net	12 Months Ended
	Dec. 31, 2017
Investment and Other Income, Net [Abstract]
Investment and Other Income, Net	 (9) Investment and Other Income, Net : The components of investment and other income, net for t he years ended December 31, 2017 , 201 6 and 201 5 are as follows:     ( $ in millions ) 2017 2016 2015   Interest and dividend income $ 6 $ 13 $ 7  Gain on expiration/settlement of customer advances - 13 -  All other, net (3) 1 -  Total investment and other income, net $ 3 $ 27 $ 7   During 201 6 , we recognized income of $13 million in connection with certain retained liabilities that have terminated, associated with customer advances for construction from our disposed water properties.

Capital Stock

Capital Stock	12 Months Ended
	Dec. 31, 2017
Capital Stock [Abstract]
Capital Stock	(10) Capital Stock : We are authorized to issue up to 175,000,000 shares of common stock and 50,000,000 shares of preferred stock. The amount and timing of dividends payable on common and preferred stock are, subject to applicable law, within the sole discretion of our Board of Directors.  Common Stock Offering On June 10, 2015, prior to the reverse stock split (see Footnote 1) we completed a registered offering of 150,000,000 shares of our common stock, par value $0.25 per share, at an offering price of $5 per share. On June 24, 2015, Frontier issued an additional 15,000,000 shares of common stock in connection with the over-allotment option that was exercised in full by the underwriters. Aggregate net proceeds were approximately $799 million after deducting commissions and estimated expenses. We used the net proceeds from this offering to fund a portion of the acquisition price of the CTF Acquisition and related fees and expenses.  Mandatory Convertible Preferred Stock (Series A) Offering On June 10, 2015, prior to the reverse stock split, we completed a registered offering of 17,500,000 shares of our 11.125% Mandatory Convertible Preferred Stock, Series A, par value $0.01 per share (the “Series A Preferred Stock”), at an offering price of $100 per share. On June 24, 2015, Frontier issued an additional 1,750,000 shares of Series A Preferred Stock in connection with the over-allotment option that was exercised in full by the underwriters. Aggregate net proceeds of the offering were $1,866 million after deducting commissions and estimated expenses. We used the net proceeds from this offering to fund a portion of the acquisition price of the CTF Acquisition and related fees and expenses.  Unless converted earlier, each share of the Series A Preferred Stock will automatically convert on June 29, 2018 into common stock, (between 1.1348 and 1.3333 shares on a post-split basis ) depending on the applicable market value of our common stock, subject to anti-dilution adjustments. Subject to certain restrictions, at any time prior to June 29, 2018, holders of the Series A Preferred Stock may elect to convert all or a portion of their shares into common stock at the minimum conversion rate then in effect.  Dividends on shares of the Series A Preferred Stock are payable on a cumulative basis when, as and if declared by our Board of Directors (or an authorized committee thereof) at an annual rate of 11.125% on the liquidation preference of $100.00 per share, on the last business day of March, June, September and December of each year, commencing on September 30, 2015 to, and including, the mandatory conversion date. Series A Preferred Stock dividends of $214 million , $214 million , and $120 million were paid in 201 7, 201 6, and 2015 respectively.  Pursuant to the terms of the CTF Acquisition, $1,955 million of the $2,665 million in net proceeds from the equity offerings were deposited into escrow and were included in “Restricted cash” in the consolidated balance sheet as of December 31, 2015. Upon closing of the CTF Acquisition, the funds were released and used to fund a portion of the purchase price. 

Stock Plans

Stock Plans	12 Months Ended
	Dec. 31, 2017
Stock Plans [Abstract]
Stock Plans	(11) Stock Plans : At December 31, 2017, we had seven stock-based compensation plans under which grants were made and awards remained outstanding. No further awards may be granted under six of the plans: the 1996 Equity Incentive Plan (the 1996 EIP), the Amended and Restated 2000 Equity Incentive Plan (the 2000 EIP), the 2009 Equity Incentive Plan (the 2009 EIP), the 2013 Equity Incentive Plan (the 2013 EIP), the Deferred Fee Plan and the Directors’ Equity Plan. At December 31, 2017, there were approximately 5,667,000 shares authorized for grant and approximately 4,361,000 shares available for grant under the 2017 Equity Incentive Plan (the 2017 EIP and together with the 1996 EIP, the 2000 EIP, the 2009 EIP and the 2013 EIPS, the EIPs). Our general policy is to issue treasury shares upon the grant of restricted shares and the exercise of options.  1996, 2000, 2009, 2013, and 2017 Equity Incentive Plans Since the expiration dates of the 1996 EIP, the 2000 EIP, the 2009 EIP, and the 2013 EIP on May 22, 2006, May 14, 2009, May 8, 2013, and May 10, 2017, respectively, no awards have been or may be granted under the 1996 EIP, the 2000 EIP, the 2009 EIP, and the 2013 EIP. Under the 2017 EIP, awards of our common stock may be granted to eligible employees in the form of incentive stock options, non-qualified stock options, SARs, restricted stock, performance shares or other stock-based awards. As discussed under the Non-Employee Directors’ Compensation Plans below, prior to May 25, 2006 non-employee directors received an award of stock options under the 2000 EIP upon commencement of service . No awards may be granted more than 10 years after the effective date (May 10, 2017) of the 2017 EIP plan. The exercise price of stock options and SARs under the EIPs generally are equal to or greater than the fair market value of the underlying common stock on the date of grant. Stock options are not ordinarily exercisable on the date of grant but vest over a period of time (generally four years). Under the terms of the EIPs, subsequent stock dividends and stock splits have the effect of increasing the option shares outstanding, which correspondingly decrease the average exercise price of outstanding options.  Performance Shares On February 15, 2012, Frontier’s Compensation Committee, in consultation with the other non-management directors of Frontier’s Board of Directors and the Committee’s independent executive compensation consultant, adopted the Frontier Long-Term Incentive Plan (the LTIP). LTIP awards are granted in the form of performance shares. The LTIP is currently offered under Frontier’s 2009 EIP , 2013 EIP and 2017 EIP , and participants consist of senior vice presidents and above. The LTIP awards have performance, mark et and time-vesting conditions.  Beginning in 2012, during the first 90 days of a three -year performance period (a Measurement Period), a target number of performance shares are awarded to each LTIP participant with respect to the Measurement Period. The performance metrics under the LTIP are (1) annual targets for operating cash flow based on a goal set during the first 90 days of each year in the three-year Measurement Period and (2) an overall performance “modifier” set during the first 90 days of the Measurement Period, based on Frontier’s total return to stockholders (i.e., Total Shareholder Return or TSR) relative to the Integrated Telecommunications Services Group (GICS Code 50101020) for the three-year Measurement Period. Operating cash flow performance is determined at the end of each year and the annual results will be averaged at the end of the three-year Measurement Period to determine the preliminary number of shares earned under the LTIP award. The TSR performance measure is then applied to decrease or increase payouts based on Frontier’s three year relative TSR performance. LTIP awards, to the extent earned, will be paid out in the form of common stock shortly following the end of the three-year Measurement Period.  On February 25, 2015, the Compensation Committee granted approximately 665,000 performance shares under the LTIP and set the operating cash flow performance goal for 2015, which applies to the first year in the 2015-2017 measurement period, the second year of the 2014-2016 measurement period and the third year of the 2013-2015 measurement period. On February 11, 2016, the Compensation Committee granted approximately 1,669,000 performance shares under the LTIP and set the operating cash flow performance goal for 2016, which applies to the first year in the 2016-2018 measurement period, the second year of the 2015-2017 measurement period and the third year of the 2014-2016 measurement period. On February 16, 2017, the Compensation Committee of our Board of Directors granted approximately 157,400 performance shares under the Frontier Long Term Incentive Plan (the LTIP) and set the operating cash flow performance goal for 2017, which applies to the first year in the 2017-2019 measurement period, the second year of the 2016-2018 measurement period and the third year of the 2015-2017 measurement period. The number of shares of common stock earned at the end of each three-year Measurement Period may be more or less than the number of target performance shares granted as a result of operating cash flow and TSR performance. An executive must maintain a satisfactory performance rating during the Measurement Period and must be employed by Frontier at the end of the three-year Measurement Period in order for the award to vest. The Compensation Committee will determine the number of shares earned for each three year Measurement Period in February of the year following the end of the Measurement Period.  The following summary presents information regarding LTIP target performance shares as of December 31, 201 7 and changes during the three years then ended with regard to LTIP shares awarded under the 2009 EIP , 2013 EIP , and 2017 EIP :     Number of  Shares  (in thousands)  Balance at December 31, 2014 179  LTIP target performance shares granted 49  LTIP target performance shares earned (50)  LTIP target performance shares forfeited (10)  Balance at December 31, 2015 168  LTIP target performance shares granted 111  LTIP target performance shares earned (59)  LTIP target performance shares forfeited (30)  Balance at December 31, 2016 190  LTIP target performance shares granted 211  LTIP target performance shares earned (41)  LTIP target performance shares forfeited (54)  Balance at December 31, 2017 306   For purposes of determining compensation expense, the fair value of each performance share is measured at the end of each reporting period and, therefore, will fluctuate based on the price of Frontier common stock as well as performance relative to the targets. Frontier recognized an expense, included in “Selling, general, and administrative expenses” of $1 million, $6 million , and $7 million during 201 7 , 201 6 and 201 5 , respectively, for the LTIP.  Restricted Stock The following summary presents information regarding unvested restricted stock as of December 31, 201 7 and changes during the three years then ended with regard to restricted stock under the 2009 EIP , 2013 EIP , and 2017 EIP :     Weighted  Average  Number of Grant Date Aggregate  Shares Fair Value Fair Value  (in thousands) (per share) (in millions)  Balance at December 31, 2014 512 $ 71.25 $ 52  Restricted stock granted 188 $ 118.80 $ 13  Restricted stock vested (214) $ 73.35 $ 15  Restricted stock forfeited (24) $ 76.50  Balance at December 31, 2015 462 $ 88.95 $ 33  Restricted stock granted 396 $ 65.40 $ 20  Restricted stock vested (248) $ 78.90 $ 13  Restricted stock forfeited (61) $ 76.65  Balance at December 31, 2016 549 $ 78.00 $ 28  Restricted stock granted 454 $ 47.77 $ 3  Restricted stock vested (240) $ 80.86 $ 2  Restricted stock forfeited (130) $ 60.92  Balance at December 31, 2017 633 $ 58.63 $ 4   For purposes of determining compensation expense, the fair value of each restricted stock grant is estimated based on the average of the high and low market price of a share of our common stock on the date of grant. Total remaining unrecognized compensation cost associated with unvested restricted stock awards that is deferred at December 31, 201 7 was $21 million and the weighted average vesting period over which this cost is expected to be recognized is approximately 1.2 years.  We have granted restricted stock awards to employees in the form of our common stock. None of the restricted stock awards may be sold, assigned, pledged or otherwise transferred, voluntarily or involuntarily, by the employees until the restrictions lapse, subject to limited exceptions. The restrictions are time-based. Compensation expense, recognized in “Selling, general and administrative expenses”, of $18 million, $18 million and $20 million, for the years ended December 31, 201 7 , 201 6 and 201 5 , respectively, has been recorded i n connection with these grants.  Non-Employee Directors’ Compensation Plans As of October 1, 2013, stock units are credited to the director’s account in an amount that is determined as follows: the total cash value of the fees payable to the director is divided by the closing price of Frontier common stock on the grant date of the units. Units are credited to the director’s account quarterly. Directors must also elect to convert the units to either common stock (convertible on a one -to-one basis) or cash upon retirement or death.  Dividends are paid on stock units held by directors at the same rate and at the same time as we pay dividends on shares of our common stock. Dividends on stock units are paid in the form of additional stock units.  There were 9 directors participating in the Director Plans during all or part of 201 7 . The total plan units earned were 94,034 , 29,618 , and 22,279 in 201 7 , 201 6 and 201 5 , respectively .  To the extent directors elect to receive the distribution of their stock unit account in cash, they are considered liability-based awards. To the extent directors elect to receive the distribution of their stock unit accounts in common stock, they are considered equity-based awards. Compensation expense for stock units that are considered equity-based awards is based on the market value of our common stock at the date of grant. Compensation expense for stock units that are considered liability-based awards is based on the market value of our common stock at the end of each period.  In connection with the Director Plans, there were compensation costs associated with the issuance of stock units of $(5) million, $0 million and ($1) million in 2017, 2016 and 201 5, respectively . Cash compensation associated with the Director Plans was $1 million in 201 7 , 201 6 and 201 5 , respectively. These costs are recognized in “Selling, general and administrative expenses”.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2017
Income Taxes [Abstract]
Income Taxes	(12) Income Taxes : The following is a reconciliation of the provision for income taxes computed at the federal statutory rate to income taxes computed at the effective rates for the years ended December 31, 2017, 2016 and 2015:     2017 2016 2015   Consolidated tax provision at federal statutory rate 35.0 % 35.0 % 35.0 %  State income tax provisions, net of federal income  tax benefit 1.7 (0.1) 8.7  Tax reserve adjustment 0.1 0.6 (0.3)  Domestic production activities deduction - (1.9) -  Changes in certain deferred tax balances (0.4) 5.8 0.8  Goodwill impairment (19.1) - -  Federal research and development credit 0.1 1.0 1.5  Non-deductible transaction costs - - 0.4  Deferred Tax Remeasurement - 2017 Tax Reform 26.1 - -  All other, net (0.1) (0.2) (0.3)  Effective tax rate 43.4 % 40.2 % 45.8 %  Income taxes for the year ended December 31, 2017 includes the tax impact of $608 million related to the goodwill impairment recorded during the year.  On December 22, 2017, the U.S. government enacted comprehensive tax legislation known as the Tax Cut and Jobs Act (the TCJA). The TCJA, makes broad and complex changes to the U.S. tax code. The TCJA reduces the corporate tax rate to 21% , effective January 1, 2018. Under ASC 740, the effects of new legislation are recognized upon enactment. Accordingly, recognition of the tax effects of the TCJA is required in the interim and annual periods that include December 22, 2017.  On December 22, 2017, the SEC staff issued Staff Accounting Bulletin No. 118 (“SAB 118”), which provides guidance on accounting for the tax effects of the TCJA. SAB 118 provides a measurement period that should not extend beyond one year from the TCJA enactment date for companies to complete the accounting under ASC 740, Income Taxes. In accordance with SAB 118, a company must reflect the income tax effects of those aspects of the TCJA for which the accounting under ASC 740 is complete. To the extent that a company’s accounting for certain income tax effects of the TCJA is incomplete but it is able to determine a reasonable estimate, it must record a provisional estimate in the financial statements.  As a result of the reduction of the federal corporate income tax rate, we revalued our net deferred tax liability, as of December 31, 2017. We have recorded a net tax benefit of $830 million to value the liability using the new, lower federal tax rate. Our effective tax rate increased to 43.4% primarily as a result of the revaluation of our net deferred tax liability, partially offset by the 19.1% detriment related to the goodwill impairments. The components of the provisional net tax expense recorded in 2017 are based on currently available information and additional information needs to be prepared, obtained and/or analyzed to determine the final amounts. The provisional tax benefit for the re-measurement of deferred taxes will require additional information necessary for the preparation of our U.S. federal tax return, and further analysis and interpretation of certain provisions of the TCJA impacting deferred taxes, for example, 100% expensing of qualified assets as well as deferred tax items arising from items of income or loss recorded in other comprehensive income, could impact our tax balances as of December 31, 2017.  Income taxes for 2016 include the impact of $36 million of tax benefits resulting primarily from the adjustment of deferred tax balances due to the CTF Acquisition, the impact of $6 million in benefits from the Federal research and development credits, along with a $12 million reversal of benefits related to the domestic production activities deduction.  Income taxes for 2015 include the impact of a $3 million benefit arising from the adjustment of deferred tax balances and a $5 million benefit from the federal research and development credit.  Amounts pertaining to income tax related accounts of $0 and $55 million are included in “Income taxes and other current assets” in the consolidated balance sheets as of December 31, 2017 and 2016, respectively.  In 2017 and 2016, we received federal and state income tax refunds totaling $51 million and $120 m illion, respectively.  The components of the net deferred income tax liability (asset) at December 31 are as follows:     ( $ in millions ) 2017 2016   Deferred income tax liabilities:  Property, plant and equipment basis differences $ 2,022 $ 2,751  Intangibles 140 878  Deferred revenue/expense 8 14  Other, net 4 12  $ 2,174 $ 3,655   Deferred income tax assets:  Pension liability 176 273  Tax operating loss carryforward 960 687  Employee benefits 192 255  Accrued expenses 23 44  Lease obligations 39 75  Tax credit 43 30  Allowance for doubtful accounts 7 44  Other, net 2 2  1,442 1,410  Less: Valuation allowance (407) (271)  Net deferred income tax asset 1,035 1,139  Net deferred income tax liability $ 1,139 $ 2,516    Our federal net operating loss carryforward as of December 31, 2017 is estimated at $2.1 billion. The federal loss carryforward will begin to expire after 203 6 , unless otherwise used.  Our state tax operating loss carryforward as of December 31, 2017 is estimated at $9. 3 billion. A portion of our state loss carryforward will continue to expire annually through 2037, unless otherwise used.  Our federal research and development credit and alternative minimum tax credit as of December 31, 2017 is estimated at $18 million and $3 million, respectively. The federal research and development credit will expire between 2034 and 203 7 , unless otherwise used.  Our various state credits as of December 31, 2017 are estimated at $27 million. The state credits will expire between 2018 and 2022, unless otherwise used.  As of December 31, 2017, Frontier has a valuation allowance of $407 million to reduce deferred tax assets to an amount more likely than not to be realized. This valuation allowance is related to state net operating losses and state tax credits. In evaluating Frontier’s ability to realize its deferred tax assets, management considers whether it is more likely than not that some or all of the deferred tax assets will not be realized. Management also considered the projected reversal of deferred tax liabilities and projected future taxable income in making this assessment. Based upon this assessment, management believes it is more likely than not Frontier will realize the benefits of these deductible differences, net of valuation allowance. There was a valuation allowance of $271 million recorded as of December 31, 2016.  The provision (benefit) for federal and state income taxes, as well as the taxes charged or credited to equity of Frontier, includes amounts both payable currently and deferred for payment in future periods as indicated below:      ( $ in millions ) 2017 2016 2015   Income tax expense (benefit):  Current:  Federal $ (4) $ (52) $ 8  State 5 7 (6)  Total Current 1 (45) 2   Deferred:  Federal (1,312) (145) (126)  State (72) (60) (41)  Total Deferred (1,384) (205) (167)  Total income tax expense (benefit) (1,383) (250) (165)   Income taxes charged (credited) to equity of Frontier:  Utilization of the benefits arising from restricted stock (1) (5) -  Deferred income taxes (benefits) arising from the recognition  of additional pension/OPEB liability 7 (21) 36   Total income taxes charged (credited) to equity of Frontier 6 (26) 36  Total income taxes $ (1,377) $ (276) $ (129)   U.S. GAAP requires applying a “more likely than not” threshold to the recognition and derecognition of uncertain tax positions either taken or expected to be taken in Frontier’s income tax returns. The total amount of our gross tax liability for tax positions that may not be sustained under a “more likely than not” threshold amounts to $12 million as of December 31, 2017 including interest of $1 million. The amount of our uncertain tax positions, for which it is reasonably possible that the total amounts of unrecognized tax benefits will significantly increase or decrease during the next twelve months, and which would affect our effective tax rate, is $3 million as of December 31, 2017.  Frontier’s policy regarding the classification of interest and penalties is to include these amounts as a component of income tax expense. This treatment of interest and penalties is consistent with prior periods. We are subject to income tax examinations generally for the years 2013 forward for federal and 2008 forward for state filing jurisdictions. We also maintain uncertain tax positions in various state jurisdictions.  The following table sets forth the changes in Frontier’s balance of unrecognized tax benefits for the years ended December 31, 2017 and 2016:     ($ in millions) 2017 2016   Unrecognized tax benefits - beginning of year $ 16 $ 19  Gross increases - prior year tax positions - 3  Gross increases - current year tax positions 3 3  Gross decreases - FIN 48 liability release (7) (9)  Gross decreases - expired statute of limitations - -  Unrecognized tax benefits - end of year $ 12 $ 16  The amounts above exclude $1 million of accrued interest as of December 31, 2017 and 2016, respectively, that we have recorded and would be payable should Frontier’s tax positions not be sustained .

Net Loss Per Common Share

Net Loss Per Common Share	12 Months Ended
	Dec. 31, 2017
Net Loss Per Common Share [Abstract]
Net Loss Per Common Share	 (13) Net Loss Per Common Share : The reconciliation of the net loss per common share calculation for the years ended December 31, 201 7 , 201 6 and 201 5 is as follows :           ( $ in millions and shares in thousands, except per share amounts ) 2017 2016 2015   Net loss used for basic and diluted earnings (loss)  per share:  Net loss attributable to Frontier common shareholders $ (2,018) $ (587) $ (316)  Less: Dividends paid on unvested restricted stock awards (2) (3) (3)  Total basic net loss attributable to Frontier  common shareholders $ (2,020) $ (590) $ (319)   Effect of loss related to dilutive stock units - - -  Total diluted net loss attributable to Frontier  common shareholders $ (2,020) $ (590) $ (319)   Basic earnings (loss) per share:  Total weighted average shares and unvested restricted stock  awards outstanding - basic 78,409 78,142 72,787  Less: Weighted average unvested restricted stock awards (673) (535) (479)  Total weighted average shares outstanding - basic 77,736 77,607 72,308   Basic net loss per share attributable to Frontier  common shareholders $ (25.99) $ (7.61) $ (4.41)   Diluted earnings (loss) per share:  Total weighted average shares outstanding - basic 77,736 77,607 72,308  Effect of dilutive shares - - -  Total weighted average shares outstanding - diluted 77,736 77,607 72,308   Diluted net loss per share attributable to Frontier  common shareholders $ (25.99) $ (7.61) $ (4.41)     In calculating diluted net loss per common share for the years ended December 31, 201 7, 201 6 , and 2015 the effect of all common stock equivalents is excluded from the computation as th e effect would be antidilutive.  Stock Options For the years ended December 31, 201 7 , 201 6 and 201 5 , options to purchase 1,334 , 2,667 and 3,333 shares, respectively, issuable under employee compensation plans were excluded from the computation of diluted earnings (loss) per share (EPS) for those periods because the exercise prices were greater than the average market price of our common stock and, therefore, the effect would be antidilutive.  Stock Units At December 31, 201 7 , 201 6 and 201 5 , we had 203,952, 125,431, and 95,812 stock units, respectively, issued under the Director Plans and the 2013 EIP. These securities have not been included in the diluted income per share of common stock calculation because their inclusion would have an antidilutive effect.  Mandatory Convertible Preferred Stock The impact of the common share equivalents associated with approximately 19,250,000 shares of Series A Preferred stock described above were not included in the calculation of diluted EPS as of December 31, 201 7 and 201 6 , as their impact was antidilutive.

Comprehensive Loss

Comprehensive Loss	12 Months Ended
	Dec. 31, 2017
Comprehensive Loss [Abstract]
Comprehensive Loss	(14) Comprehensive Loss : Comprehensive income (loss) consists of net income (loss) and other gains and losses affecting shareholders’ investment and pension/postretirement benefit (OPEB) liabilities that, under GAAP, are excluded from net income/(loss).  The components of accumulated other comprehensive loss, net of tax at December 31, 2017, 2016 and 2015, and changes for the years then ended, are as follows :     ($ in millions) Pension Costs OPEB Costs Total  Balance at December 31, 2014 (a) $ (330) $ (74) $ (404)  Other comprehensive income (loss) before reclassifications (51) 82 31  Amounts reclassified from accumulated other comprehensive income (loss) 18 2 20  Net current-period other comprehensive income (loss) (33) 84 51  Balance at December 31, 2015 (a) (363) 10 (353)  Other comprehensive income (loss) before reclassifications (65) 11 (54)  Amounts reclassified from accumulated other comprehensive income (loss) 25 (5) 20  Net current-period other comprehensive income (loss) (40) 6 (34)  Balance at December 31, 2016 (a) (403) 16 (387)  Other comprehensive income (loss) before reclassifications (12) (31) (43)  Amounts reclassified from accumulated other comprehensive income (loss) 70 (6) 64  Net current-period other comprehensive income (loss) 58 (37) 21  Balance at December 31, 2017 (a) $ (345) $ (21) $ (366)    (a) Pension and OPEB amounts are net of deferred tax balances of $223 million, $231 million, $211 million, and $247 million as of December 31, 2017, 2016, 2015, and 2014, respectively  As a result of the pension settlement accounting discussed in Note 17, Frontier recorded pension settlement charges totaling $83 million ( $51 million net of tax), which were reclassified from accumulated Other comprehensive income (loss) during 2017.  As a result of the CTF Acquisition, the Frontier Communications Pension Plan (the Plan) was remeasured. This remeasurement resulted in a decrease in the discount rate from 4.50% at December 31, 2015 to 4.00% at the date of the CTF Acquisition. This change in the discount rate resulted in a remeasurement charge to Other comprehensive income (loss) of $105 million during 2016 . The significant items reclassified from each component of accumulated other comprehensive loss for the years ended December 31, 2017, 2016 and 2015 are as follows :       Amount Reclassified from  ($ in millions) Accumulated Other Comprehensive Loss (a)   Details about Accumulated Other Comprehensive Loss Components 2017 2016 2015 Affected Line Item in the Statement Where Net loss is Presented   Amortization of Pension Cost Items (b)  Actuarial gains (losses) $ (30) $ (40) $ (29)  Pension settlement costs (83) - -  Reclassifications, pretax (113) (40) (29) loss before income taxes  Tax Impact 43 15 11 Income tax (expense) benefit  Reclassifications, net of tax $ (70) $ (25) $ (18) Net loss   Amortization of OPEB Cost Items (b)  Prior-service credits/(costs) $ 9 $ 9 $ 5  Actuarial gains (losses) - (1) (8)  Reclassifications, pretax 9 8 (3) loss before income taxes  Tax impact (3) (3) 1 Income tax (expense) benefit  Reclassifications, net of tax $ 6 $ 5 $ (2) Net loss      (a) Amounts in parentheses indicate losses. (b) These accumulated other comprehensive loss components are included in the computation of net periodic pension and OPEB costs (see Note 17 - Retirement Plans for additional details ) .

Segment Information

Segment Information	12 Months Ended
	Dec. 31, 2017
Segment Information [Abstract]
Segment Information	(15) Segment Information : We operate in one operating and one reportable segment. Frontier provides both regulated and unregulated voice, data and video services to consumer and commercial customers and is typically the incumbent voice services provider in its service areas. 

Quarterly Financial Data

Quarterly Financial Data	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Data [Abstract]
Quarterly Financial Data	(16) Quarterly Financial Data (Unaudited ) :      ($ in millions, except per share amounts) First Quarter Second Quarter Third Quarter Fourth Quarter Total Year  2017   Revenue $ 2,356 $ 2,304 $ 2,251 $ 2,217 $ 9,128   Operating income (loss) 271 (394) 309 (1,754) (1,568)   Net loss attributable to Frontier  common shareholders (1) (2) (129) (715) (92) (1,082) (2,018)   Basic net loss per share attributable  to Frontier common shareholders (1) (2) $ (1.67) $ (9.20) $ (1.19) $ (13.91) $ (25.99)   Diluted net loss per share attributable  to Frontier common shareholders (1) (2) $ (1.67) $ (9.21) $ (1.19) $ (13.91) $ (25.99)  (1) During the fourth quarter of 2017, we recorded a goodwill impairment charge of $2,078 million ( $1,822 million after-tax). Refer to Note 6 for further details. (2) The quarterly net loss per share amounts are rounded to the nearest cent. Annual net loss per share may vary depending on the effect of such rounding.        ($ in millions, except per share amounts) First Quarter Second Quarter Third Quarter Fourth Quarter Total Year   2016   Revenue $ 1,355 $ 2,608 $ 2,524 $ 2,409 $ 8,896   Operating income 58 311 264 255 888   Net loss attributable to Frontier  common shareholders (1) (2) (4) (240) (80) (134) (133) (587)   Basic net loss per share attributable  to Frontier common shareholders (1) (2) (3) (4) $ (3.10) $ (1.05) $ (1.73) $ (1.73) $ (7.61)   Diluted net loss per share attributable  to Frontier common shareholders (1) (2) (3) (4) $ (3.10) $ (1.05) $ (1.73) $ (1.73) $ (7.61)    (1) During the fourth quarter of 2016, we recorded acquisition and integration expenses of $49 million ( $48 million after-tax) related to the CTF acquisition in June 2016. (2) During the fourth quarter of 201 6 , we recorded restructuring costs and other charges of $80 million ( $52 million after-tax) related to severance expense and special termination benefits resulting from a reduction in the workforce. (3) The quarterly net loss per share amounts are rounded to the nearest cent. Annual net loss per share may vary depending on the effect of such rounding. (4) The change in revenue, operating income, net loss, and net loss per share during the second quarter of 2016 and each subsequent quarter of 2016 reflects additional results of the CTF Operations related to the CTF Acquisition, as described further in Note 3.

Retirement Plans

Retirement Plans	12 Months Ended
	Dec. 31, 2017
Retirement Plans [Abstract]
Retirement Plans	(17) Retirement Plans : We sponsor a noncontributory defined benefit pension plan covering a significant number of our former and current employees and other postretirement benefit plans that provide medical, dental, life insurance and other benefits for covered retired employees and their beneficiaries and covered dependents. The pension plan and postretirement benefit plans are closed to the majority of our newly hired employees. The benefits are based on years of service and final average pay or career average pay. Contributions are made in amounts sufficient to meet ERISA funding requirements while considering tax deductibility. Plan assets are invested in a diversified portfolio of equity and fixed-income securiti es and alternative investments.  The accounting results for pension and other postretirement benefit costs and obligations are dependent upon various actuarial assumptions applied in the determination of such amounts. These actuarial assumptions include the following: discount rates, expected long-term rate of return on plan assets, future compensation increases, employee turnover, healthcare cost trend rates, expected retirement age, optional form of benefit and mortality. We review these assumptions for changes annually with our independent actuaries. We consider our discount rate and expected long-term rate of return on plan assets to be our most critical assumptions.  The discount rate is used to value, on a present value basis, our pension and other postretirement benefit obligations as of the balance sheet date. The same rate is also used in the interest cost component of the pension and postretirement benefit cost determination for the following year. The measurement date used in the selection of our discount rate is the balance sheet date. Our discount rate assumption is determined annually with assistance from our independent actuaries based on the pattern of expected future benefit payments and the prevailing rates available on long-term, high quality corporate bonds that approximate the benefit obligation.  As of December 31, 201 7 , 201 6 and 201 5 , we utilized an estimation technique that is based upon a settlement model (Bond:Link) that permits us to closely match cash flows to the expected payments to participants. This rate can change from year-to-year based on market conditions that affect corporate bond yields.  As a result of the technique described above, Frontier is utilizing a discount rate of 3.70% as of December 31, 201 7 for its qualified pension plan, compared to rates of 4.10% and 4.50% in 201 6 and 201 5 , respectively. The discount rate for postretirement plans as of December 31, 201 7 was a range of 3.70% to 3.80% compared to a range of 4.10% to 4.30% in 201 6 and 4.50% to 4.70% in 201 5 .  The Pension Plan contains provisions that provide certain employees with the option of receiving a lump sum payment upon retirement. Frontier’s accounting policy is to record these payments as a settlement only if, in the aggregate, they exceed the sum of the annual service and interest costs for the Pension Plan’s net periodic pension benefit cost. During year ended December 31, 2017, lump sum pension settlement payments to terminated or retired individuals amounted to $486 million, which exceeded the settlement threshold of $224 million, and as a result, Frontier recognized non-cash settlement charges totaling $83 million during 2017. The non-cash charge accelerated the recognition of a portion of the previously unrecognized actuarial losses in the Pension Plan. These non-cash charges increased our recorded net loss and accumulated deficit, with an offset to accumulated other comprehensive loss in shareholders’ equity.  As a result of the CTF Acquisition, the Frontier Communications Pension Plan (the Plan) was remeasured. This remeasurement resulted in a decrease in the discount rate from 4.50% at December 31, 2015 to 4.00% at the date of the CTF Acquisition. This change in the discount rate resulted in a remeasurement charge to other comprehensive income (loss) of $105 million during 2016.  The expected long-term rate of return on plan assets is applied in the determination of periodic pension and postretirement benefit cost as a reduction in the computation of the expense. In developing the expected long-term rate of return assumption, we considered published surveys of expected market returns, 10 and 20 year actual returns of various major indices, and our own historical 5 year, 10 year and 20 year investment returns. The expected long-term rate of return on plan assets is based on an asset allocation assumption of 40% in long-duration fixed income securities, and 60% in equity securities and other investments. We review our asset allocation at least annually and make changes when considered appropriate. Our pension asset in vestment allocation decisions are made by the Retirement Investment & Administration Committee (RIAC), a committee comprised of members of management, pursuant to a delegation of authority by the Retirement Plan Committee of the Board of Directors. The RIAC is responsible for reporting its actions to the Retirement Plan Committee. Asset allocation decisions take into account expected market return assumptions of various asset classes as well as expected pension benefit payment streams. When analyzing anticipated benefit payments, management considers both the absolute amount of the payments as well as the timing of such payments. In 201 7 , 201 6 and 201 5 , our expected long-term rate of return on plan assets was 7.50% , 7.50% , and 7.75% , respectively. For 201 8 , we will assume a rate of return of 7.50% . O ur pension plan assets are valued at fair value as of the measurement date. The measurement date used to determine pension and other postretirement benefit measures for the pension plan and the postreti rement benefit plan is December 31. The remeasured funded status of the Pension Plan was approximately 80% , as of December 31, 2017, similar to December 31, 2016.  Pension Benefits  The following tables set forth the pension plan’s projected benefit obligations, fair values of plan assets and the pension benefit liability recognized on our consolidated balance sheets as of December 31, 201 7 and 201 6 and the components of total pension benefit cost for the years ended December 31, 201 7 , 201 6 and 201 5 :       ( $ in millions ) 2017 2016   Change in projected benefit obligation (PBO)  PBO at beginning of year $ 3,465 $ 2,142  Service cost 97 88  Interest cost 127 122  Actuarial (gain)/loss 214 137  Benefits paid (59) (155)  CTF Acquisition PBO - 1,108  Settlements (486) -  Special termination benefits 5 23  PBO at end of year $ 3,363 $ 3,465   Change in plan assets  Fair value of plan assets at beginning of year $ 2,766 $ 1,572  Fair value of plan assets for the CTF operations as of acquisition date - 1,120  Actual return on plan assets 378 201  Employer contributions 206 28  Settlements (486) -  Differential payment received from Verizon (131) -  Benefits paid (59) (155)  Fair value of plan assets at end of year $ 2,674 $ 2,766   Funded status $ (689) $ (699)   Amounts recognized in the consolidated balance sheet  Pension and other postretirement benefits - current $ - $ -  Pension and other postretirement benefits - noncurrent $ (689) $ (699)  Accumulated other comprehensive loss $ 556 $ 647   In connection with the completion of the CTF Acquisition, certain employees were transferred to the Frontier Communications Pension Plan (the Plan) effective April 1, 2016. Assets of $1, 108 million related to the CTF Acquisition were transferred from Verizon and the Verizon pension plan trusts during 2016 .      ( $ in millions ) 2017 2016 2015   Components of total pension benefit cost  Service cost $ 97 $ 88 $ 55  Interest cost on projected benefit obligation 127 122 88  Expected return on plan assets (186) (168) (129)  Amortization of unrecognized loss 30 40 29  Net periodic pension benefit cost 68 82 43  Pension settlement costs 83 - -  Special termination benefits 5 23 -  Total pension benefit cost $ 156 $ 105 $ 43    The expected amortization of deferred unrecognized loss , included in Other comprehensive income, in 201 8 is $26 million.  We capitalized $26 million, $25 million and $20 million of pension and OPEB expense into the cost of our capital expenditures during the years ended December 31, 201 7 , 201 6 and 201 5 , respectively, as the costs relate to our engineering and plant construction activities .  The plan’s weighted average asset allocations at December 31, 201 7 and 201 6 by asset category are as follows :       2017 2016  Asset category:  Equity securities 50 % 50 %  Debt securities 40 % 38 %  Alternative investments 10 % 11 %  Cash and other - % 1 %  Total 100 % 100 %   The plan’s expected benefit payments over the next 10 years are as follows :       ($ in millions) Amount   2018 $ 265  2019 256  2020 251  2021 245  2022 237  2023-2027 1,122  Total $ 2,376   We made total contributions to our pension plan of $75 million , net of the Differential (as defined below), during 201 7.  As part of the CTF Acquisition, Verizon was required to make a cash payment to Frontier for the difference in assets initially transferred by Verizon into the Pension Plan and the related obligation (the Differential). In 2017, we received the $131 million Differential payment from Verizon, and have remitted an equivalent amount to the Pension Plan as of December 31 , 2017. As the Differential was reflected as a receivable of the Pension Plan at December 31, 2016, the cash funding had no impact to plan assets.  See Note 7 for further discussion of a Frontier contribut ion of real estate property in 2016 with an aggregate fair value of $15 million for the purpose of funding a portion of its contribution obligations to the Plan. We made total cash contributions to our pension plan during 201 6 and 201 5 of $ 13 million and $62 million, respectively.  The accumulated benefit obligation for the plan was $3,363 million and $3,465 million at December 31, 201 7 and 201 6 , respectively.  Assumptions used in the computation of annual pension costs and valuation of the year-end obligations were as follows :      2017 2016 2015  Discount rate - used at year end to value obligation 3.70 % 4.10 % 4.50 %  Discount rate - used to compute annual cost 4.10 % 4.50 % 4.10 %  Expected long-term rate of return on plan assets 7.50 % 7.50 % 7.75 %  Rate of increase in compensation levels 2.50 % 2.50 % 2.50 %   Postretirement Benefits Other Than Pensions—“OPEB”  The following tables set forth the OPEB plans’ benefit obligations, fair values of plan assets and the postretirement benefit liability recognized on our consolidated balance sh eets as of December 31, 2017 and 201 6 and the components of total postretirement benefit cost for the years ended December 31, 201 7 , 201 6 and 201 5 .       ( $ in millions) 2017 2016   Change in benefit obligation  Benefit obligation at beginning of year $ 925 $ 626  CTF Acquisition PBO - 276  Service cost 21 19  Interest cost 40 37  Plan participants' contributions 7 5  Actuarial (gain)/loss 54 (18)  Benefits paid (31) (23)  Special termination benefits - 3  Benefit obligation at end of year $ 1,016 $ 925   Change in plan assets  Fair value of plan assets at beginning of year $ - $ -  Plan participants' contributions 7 5  Employer contribution 24 18  Benefits paid (31) (23)  Fair value of plan assets at end of year $ - $ -   Funded status $ (1,016) $ (925)   Amounts recognized in the consolidated balance sheet  Pension and other postretirement benefits - current $ (29) $ (23)  Pension and other postretirement benefits - noncurrent $ (987) $ (902)  Accumulated other comprehensive (gain)/loss $ 33 $ (29)        ( $ in millions ) 2017 2016 2015   Components of total postretirement benefit cost  Service cost $ 21 $ 19 $ 19  Interest cost on projected benefit obligation 40 37 30  Amortization of prior service (credit)/costs (9) (9) (5)  Amortization of unrecognized loss - 1 8  Net periodic postretirement benefit cost 52 48 52  Special termination benefits - 3 -  Total postretirement benefit cost $ 52 $ 51 $ 52   The expected amortization of prior service credit in 201 8 is $9 million and the expected amortization of unrecognized loss in 201 8 is $2 million .  Assumptions used in the computation of annual OPEB costs and valuation of the year-end OPEB obligations were as follows :      2017 2016 2015  Discount rate - used at year end to value obligation 3.70% - 3.80% 4.10% - 4.30% 4.50% - 4.70%  Discount rate - used to compute annual cost 4.10% - 4.30% 4.50% - 4.70% 4.10% - 4.20%   The OPEB plan’s expected benefit payments over the next 10 years are as follows :       ($ in millions) Gross Benefit Medicare Part D Subsidy Total   2018 $ 30 $ - $ 30  2019 37 - 37  2020 44 - 44  2021 49 - 49  2022 52 - 52  2023-2027 306 2 308  Total $ 518 $ 2 $ 520   For purposes of measuring year-end benefit obligations, we used, depending on medical plan coverage for different retiree groups, a 6.75% annual rate of increase in the per-capita cost of covered medical benefits, gradually decreasing to 5.00% in the year 202 5 and remaining at that level thereafter. The effect of a 1% increase in the assumed medical cost trend rates for each future year on the aggregate of the service and interest cost components of the total postretirement benefit cost would be $1 million and the effect on the accumulated postretirement benefit obligation for health benefits would be $22 million. The effect of a 1% decrease in the assumed medical cost trend rates for each future year on the aggregate of the service and interest cost components of the total postretirement benefit cost would be $(1) million and the effect on the accumulated postretirement benefit obligation for health benefits would be $(22) million . The amounts in accumulated other comprehensive (gain) / loss before tax that have not yet been recognized as components of net periodic benefit cost at December 31, 201 7 and 201 6 are as follows :       Pension Plan OPEB  ( $ in millions ) 2017 2016 2017 2016  Net actuarial loss $ 556 $ 647 $ 54 $ 1  Prior service cost/(credit) - - (21) (30)  Total $ 556 $ 647 $ 33 $ (29)   The amounts recognized as a component of accumulated other comprehensive loss for the years ended December 31, 201 7 and 201 6 are as follows :      Pension Plan OPEB  ( $ in millions ) 2017 2016 2017 2016  Accumulated other comprehensive (gain)/loss at  beginning of year $ 647 $ 584 $ (29) $ (20)   Net actuarial gain/(loss) recognized during year (30) (40) - (1)  Prior service (cost)/credit recognized during year - - 9 9  Net actuarial loss/(gain) occurring during year 22 103 53 (17)  Settlement loss recognized (83) - - -  Net amount recognized in comprehensive income  (loss) for the year (91) 63 62 (9)  Accumulated other comprehensive (gain)/loss at  end of year $ 556 $ 647 $ 33 $ (29)   401(k) Savings Plans We sponsor employee retirement savings plans under section 401(k) of the Internal Revenue Code. The plans cover substantially all full-time employees. Under certain plans, we provide matching contributions. Employer contributions were $48 million, $48 million and $28 million for 201 7 , 201 6 and 201 5 , respectively .

Fair Value Of Financial Instrum

Fair Value Of Financial Instruments	12 Months Ended
	Dec. 31, 2017
Fair Value Of Financial Instruments [Abstract]
Fair Value Of Financial Instruments	(18) Fair Value of Financial Instruments : Fair value is defined under GAAP as the exit price associated with the sale of an asset or transfer of a liability in an orderly transaction between market participants at the measurement date. Valuation techniques used to measure fair value under GAAP must maximize the use of observable inputs and minimize the use of unobservable inputs. In addition, GAAP establishes a three-tier fair value hierarchy, which prioritizes the input s used in measuring fair value.  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 prices in active markets for identical assets. 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 tables represent Frontier’s pension plan assets measured at fair value on a recurring basis as of December 31, 201 7 and 201 6 :       Fair Value Measurements at December 31, 2017  ( $ in millions ) Total Level 1 Level 2 Level 3  Cash and Cash Equivalents $ 37 $ 37 $ - $ -  U.S. Government Obligations 30 - 30 -  Corporate and Other Obligations 448 - 448 -  Common Stock 523 523 - -  Common/Collective Trusts 1,215 - 1,215 -  Interest in Registered Investment Companies 324 324 - -  Interest in Limited Partnerships and  Limited Liability Companies 115 - - 115  Total investments at fair value $ 2,692 $ 884 $ 1,693 $ 115  Interest and Dividend Receivable 6  Due from Broker for Securities Sold 40  Receivable Associated with Insurance Contract 7  Due to Broker for Securities Purchased (71)  Total Plan Assets, at Fair Value $ 2,674        Fair Value Measurements at December 31, 2016  ( $ in millions ) Total Level 1 Level 2 Level 3  Cash and Cash Equivalents $ 42 $ 42 $ - $ -  U.S. Government Obligations 29 - 29 -  Corporate and Other Obligations 400 - 400 -  Common Stock 487 487 - -  Common/Collective Trusts 1,104 - 1,104 -  Interest in Registered Investment Companies 334 334 - -  Interest in Limited Partnerships and  Limited Liability Companies 118 - - 118  Total investments at fair value $ 2,514 $ 863 $ 1,533 $ 118  Receivable for plan assets of the CTF Operations 258  Interest and Dividend Receivable 6  Due from Broker for Securities Sold 27  Receivable Associated with Insurance Contract 7  Due to Broker for Securities Purchased (46)  Total Plan Assets, at Fair Value $ 2,766   There have been no reclassifications of investments between Levels 1, 2 or 3 assets during the years ended December 31, 201 7 or 201 6 .  The tables below set forth a summary of changes in the fair value of the Plan’s Level 3 assets for the years ended December 31, 201 7 and 201 6 :      Interest in Limited Partnerships and Limited Liability Companies  ( $ in millions ) 2017 2016  Balance, beginning of year $ 118 $ 92  Realized gains 12 7  Unrealized gains/(losses) (2) 13  Purchases - 15  Sales and distributions (13) (9)  Balance, end of year $ 115 $ 118   The following table provides further information regarding the redemption of the Plan’s Level 3 investments as well as information related to significant unobservable inputs and the range of values for those inputs for the Plan’s interest in certain limited partnerships and limited liability companies as of December 31, 201 7 :       ( $ in millions ) Fair Value Liquidation Period Capitalization Rate  Interest in Limited Partnerships and Limited  Liability Companies (d)   MS IFHF SVP LP Cayman (a) $ 1 5 years N/A  MS IFHF SVP LP Alpha (a) 1 5 years N/A  RII World Timberfund, LLC (b) 5 10 years N/A  426 E Casino Road, LLC (c) 15 N/A 7.00%  100 Comm Drive, LLC (c) 9 N/A 8.00%  100 CTE Drive, LLC (c) 10 N/A 9.50%  6430 Oakbrook Parkway, LLC (c) 26 N/A 7.75%  8001 West Jefferson, LLC (c) 26 N/A 8.75%  1500 MacCorkle Ave SE, LLC (c) 14 N/A 8.50%  400 S. Pike Road West, LLC (c) 1 N/A 8.50%  601 N US 131, LLC (c) 1 N/A 9.50%  9260 E. Stockton Blvd., LLC (c) 6 N/A 7.50%  Total Interest in Limited Partnerships and Limited  Liability Companies $ 115   (a) The partnerships’ investment objective is to seek capital appreciation principally through investing in investment funds managed by third party investment managers who employ a variety of alternative investment strategies. These instruments are subject to certain withdrawal restrictions. The Plan is in the process of liquidating its interest in the partnerships and distributions are expected to be made over the next four years. (b) The fund’s objective is to realize substantial long-term capital appreciation by investing in timberland properties primarily in South America and Australia. This investment is subject to certain withdrawal restrictions. (c) The entity invests in commercial real estate properties that are leased to Frontier. The leases are triple net, whereby Frontier is responsible for all expenses, including but not limited to, insurance, repairs and maintenance and payment of property taxes. (d) All Level 3 investments have the same redemption frequency (through the liquidation of underlying investments) and redemption notice period (none).  The following table summarizes the carrying amounts and estimated fair values for long-term debt at December 31, 201 7 and 201 6 . For the other financial instruments including cash, accounts receivable, restricted cash, long-term debt due within one year, accounts payable and other current liabilities, the carrying amounts approximate fair value due to the relatively short maturities of those instruments .      2017 2016   Carrying Carrying  ($ in millions) Amount Fair Value Amount Fair Value   Long-term debt $ 16,970 $ 13,994 $ 17,560 $ 17,539  The fair value of our long-term debt is estimated based upon quoted market prices at the reporting date for those financial instruments .

Commitments And Contingencies

Commitments And Contingencies	12 Months Ended
	Dec. 31, 2017
Commitments And Contingencies [Abstract]
Commitments And Contingencies	(19) Commitments and Contingencies : Although from time to time we make short-term purchasing commitments to vendors with respect to capital expenditures, we generally do not enter into firm, written contracts for such activities.  In June 2015, Frontier accepted the Federal Communications Commission’s (FCC) offer of support to price cap carriers under the Connect America Fund (CAF) Phase II program, which is intended to provide long-term support for broadband in high cost unserved or underserved areas. This program provides $332 million in annual support, including $49 million in annual support related to the properties acquired in the CTF Acquisition, through 2020 to make available 10 Mbps downstream/1 Mbps upstream broadband service to approximately 774,000 households across certain of the 29 states where we now operate. To the extent we do not enable the required number of households with 10 Mbps downstream/1 Mbps upstream broadband service by the end of the CAF Phase II term, we will be required to return a portion of the funds previously received.  On April 28, 2016, the FCC completed its inquiry into whether certain terms and conditions contained in specifically identified special access tariff pricing plans offered by four carriers, including Frontier, are just and reasonable. The FCC held that certain of the tariff terms for business data TDM services, specifically DS1s and DS3s, were unreasonable. Specifically, the FCC struck down “excessive” early termination fees and “all-or-nothing” provisions. Frontier has revised its tariffs in accordance with the FCC’s Order. The FCC’s decision has no retroactive effect, and we anticipate no material impact to Frontier from it.  The FCC deferred the issue of how its ruling will affect customers currently purchasing services from these tariffs to a Notice of Proposed Rulemaking. It is seeking comment on proposed changes to the way the FCC regulates traditional special access services and , on a proposal , to adopt pricing rules for Ethernet services in markets that are found to be “noncompetitive.” The potential impact to Frontier of this proceeding is unknown, though any pending initiative could adversely affect our operations or financial results.  We are party to various legal proceedings (including individual, class and putative class actions, governmental investigations) arising in the normal course of our business covering a wide range of matters and types of claims including, but not limited to, general contracts, billing disputes, rights of access, taxes and surcharges, consumer protection, advertising, trademark and patent infringement, employment, regulatory, tort, claims of competitors and disputes with other carriers. Litigation is subject to uncertainty and the outcome of individual matters is not predictable. However, we believe that the ultimate resolution of all such matters, after considering insurance coverage or other indemnities to which we are entitled, will not have a material adverse effect on our financial position, results of operations, or cash flows.  In October 2013, the California Attorney General’s Office notified certain Verizon companies, including one of the subsidiaries that we acquired in the CTF Acquisition, of potential violations of California state hazardous waste statutes primarily arising from the disposal of electronic components, batteries and aerosol cans at certain California facilities. We are cooperating with this investigation. We have accrued an amount for potential penalties that we deem to be probable and reasonably estimated, and we do not expect that any potential penalties, if ultimately incurred, will be material in comparison to the established accrual.  We accrue an expense for pending litigation when we determine that an unfavorable outcome is probable , and the amount of the loss can be reasonably estimated. Legal defense costs are expensed as incurred. None of our existing accruals for pending matters, after considering insurance coverage, is material. We monitor our pending litigation for the purpose of adjusting our accruals and revising our disclosures accordingly, when required. Litigation is, however, subject to uncertainty, and the outcome of any particular matter is not predictable. We will vigorously defend our interests in pending litigation, and as of this date, we believe that the ultimate resolution of all such matters, after considering insurance coverage or other indemnities to which we are entitled, will not have a material adverse effect on our consolidated financial position, results of operations, or our cash flows.  We conduct certain of our operations in leased premises and also lease certain equipment and other assets pursuant to operating leases. The lease arrangements have terms ranging from 1 to 99 years and several contain rent escalation clauses providing for increases in monthly rent at specific intervals. When rent escalation clauses exist, we record annual rental expense based on the total expected rent payments on a straight-line basis over the lease term. Certain leases also have renewal options. Renewal options that are reasonably assured are included in determining the lease term.  Future minimum rental commitments for all long-term noncancelable operating leases as of December 31, 201 7 are as follows :    ($ in millions) Operating Leases   Year ending December 31:  2018 $ 80  2019 25  2020 29  2021 26  2022 23  Thereafter 388  Total minimum lease payments $ 571  Total rental expense included in our consolidated statements of operations for the years ended December 31, 201 7 , 201 6 and 201 5 was $106 million, $137 million and $119 million, respectively.  We are party to contracts with several unrelated long - distance carriers. The contracts provide fees based on traffic they carry for us subject to minimum monthly fees.  At December 31, 201 7 , the estimated future payments for obligations under our noncancelable long - distance contracts and service agreements are as follows :       ($ in millions) Amount   Year ending December 31:  2018 $ 37  2019 40  2020 31  2021 7  2022 2  Thereafter 9  Total $ 126  At December 31, 201 7 , we have outstanding performance letters of credit as follows :       ($ in millions) Amount   CNA Financial Corporation (CNA) $ 49  AIG Insurance 114  Zurich 28  All other 1  Total $ 192   CNA serves as our insurance carrier with respect to casualty claims (auto liability, general liability and workers’ compensation) with dates of loss prior to June 1, 2017 (except for those claims which arise out of the operations acquired from CTF that have dates of loss prior to April 1, 2016 ). As our insurance carrier, they administer the casualty claims and make claim payments on our behalf. We reimburse CNA for such services upon presentation of their invoice. To serve as our carrier and make payments on our behalf, CNA requires that we establish a letter of credit in their favor. CNA could potentially draw against this letter of credit if we failed to reimburse CNA in accordance with the terms of our agreement. The amount of the letter of credit is reviewed annually and adjusted based on claims history.  Zurich serves as our insurance carrier with respect to casualty claims (auto liability, general liability and workers’ compensation) with dates of loss from June 1, 2017 and going forward. As our insurance carrier, they administer the casualty claims and make claim payments on our behalf. We reimburse Zurich for such services upon presentation of their invoice. To serve as our carrier and make payments on our behalf, Zurich requires that we establish a letter of credit in their favor. Zurich could potentially draw against this letter of credit if we failed to reimburse Zurich in accordance with the terms of our agreement. The amount of the letter of credit is reviewed annually and adjusted based on claims history.  AIG Insurance serves as our insurance carrier with respect to casualty claims (auto liability, general liability and workers’ compensation) that were acquired from CTF, as well as new claims which arise out of the operations acquired from CTF that have dates of loss prior to April 1, 2016. Sedgwick, a third-party claims administrator, administers the casualty claims and make claim payments on our behalf. We reimburse Sedgwick for such services upon presentation of their invoice. However, to serve as our insurance carrier, AIG Insurance requires that we establish a letter of credit in their favor. AIG Insurance could potentially draw against this letter of credit if we failed to meet the insurance-related and claims-related obligations we assumed in accordance with the terms of our agreement. The amount of the letter of credit is reviewed annually and adjusted based on claims history .

Description Of Business And S27

Description Of Business And Summary Of Significant Accounting Policies (Policy)	12 Months Ended
	Dec. 31, 2017
Description Of Business And Summary Of Significant Accounting Policies [Abstract]
Description of Business	(a) Description of Business : Frontier Communications Corporation (Frontier) is the fourth largest Incumbent Local Exchange Carrier (ILEC) in the United States, with approximately 4.9 million customers, 3.9 million broadband subscribers and 22,700 employees, operating in 29 states. Frontier was incorporated in 1935, originally under the name of Citizens Utilities Company and was known as Citizens Communications Company until July 31, 2008. Frontier and its subsidiaries are referred to as “we,” “us,” “our,” “Frontier,” or the “Company” in this report.  Effective April 1, 2016, Frontier’s scope of operations and balance sheet changed materially as a result of the completion of the CTF Acquisition, as described in Note 3 - Acquisitions. Historical financial data presented for Frontier is not indicative of the future financial position or operating results for Frontier, and includes the results of the CTF Operations, as defined in Note 3 – Acquisitions, from the date of acquisition on April 1, 2016.
Basis of Presentation and Use of Estimates	(b) Basis of Presentation and Use of Estimates : Our consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (GAAP). Certain reclassifications of amounts previously reported have been made to conform to the current presentation. All significant intercompany balances and transactions have been eliminated in consolidation.  For our financial statements as of and for the period ended December 31, 2017, we evaluated subsequent events and transactions for potential recognition or disclosure through the date that we filed this Form 10-K with the Securities and Exchange Commission (SEC).  The preparation of our financial statements in conformity with GAAP requires management to make estimates and assumptions that affect (i) the reported amounts of assets and liabilities at the date of the financial statements, (ii) the disclosure of contingent assets and liabilities, and (iii) the reported amounts of revenue and expenses during the reporting period. Actual results may differ from those estimates. Estimates and judgments are used when accounting for the allowance for doubtful accounts, asset impairments, indefinite-lived intangibles, depreciation and amortization, income taxes, business combinations, and pension and other postretirement benefits, among others.  On July 10, 2017, we effected a one for fifteen reverse stock split of our common stock. The reverse stock split reduced the number of common shares issued (which includes outstanding shares and treasury shares) from approximately 1,193,000,000 shares to 80,000,000 shares, and reduced shares outstanding from 1,178,000,000 shares to 79,000,000 shares. In addition, and at the same time, the total number of shares of common stock that Frontier is authorized to issue changed from 1,750,000,000 shares to 175,000,000 shares. There was no change in the par value of the common stock, and no fractional shares were issued. All share and per share amounts in the financial statements and footnotes have been retroactively adjusted for all periods presented to give effect to the reverse stock split. As a result of our reverse stock split the conversion rates of our Series A Preferred Stock were proportionately adjusted.
Cash Equivalents	(c) Cash Equivalents : We consider all highly liquid investments with an original maturity of three months or less to be cash equivalents. Restricted cash of $14 million is included within “Income taxes and other current assets” on our consolidated balance sheet as of December 31, 2017. This amount represents funds held as collateral by certain insurance carriers, of which $7 million was released in January 2018, and the remainder expected to be released in the first quarter of 2018.
Revenue Recognition	(d) Revenue Recognition : Revenue is recognized when services are provided or when products are delivered to customers. Revenue that is billed in advance includes monthly recurring network access services (including data services), special access services and monthly recurring voice, video and related charges. The unearned portion of these fees is initially deferred as a component of “Advanced billings” on our consolidated balance sheet and recognized as revenue over the period that the services are provided. Revenue that is billed in arrears includes non-recurring network access services (including data services), switched access services and non-recurring voice and video services. The earned but unbilled portion of these fees is recognized as revenue in our consolidated statements of operations and accrued in “Accounts Receivable” on our consolidated balance sheet in the period that the services are provided. Excise taxes are recognized as a liability when billed. Installation fees and their related direct and incremental costs are initially deferred and recognized as revenue and expense over the average term of a customer relationship. We recognize as current period expense the portion of installation costs that exceeds installation fee revenue.  Frontier collects various taxes from its customers and subsequently remits these taxes to governmental authorities. Substantially all of these taxes are recorded through the consolidated balance sheet and presented on a net basis in our consolidated statements of operations. We also collect Universal Service Fund (USF) surcharges from customers (primarily federal USF) that we have recorded on a gross basis in our consolidated statements of operations and included within “Revenue” and “Network related expenses” of $216 million, $217 million and $151 million for the years ended December 31, 2017, 2016 and 2015, respectively .  In 2015 we accepted the FCC’s Connect America Fund (CAF) Phase II offer of support, which is a successor to and augments the USF frozen high cost support that we had been receiving pursuant to a 2011 FCC order. Upon completion of the CTF Acquisition, Frontier assumed the CAF Phase II support and related obligations that Verizon had previously accepted with regard to California and Texas. CAF Phase II funding is a program intended to subsidize the high cost of establishing and delivering communications services to certain unserved or underserved areas. We are recognizing these subsidies into revenue on a straight line basis, which is consistent with how the costs related to these subsidies are being and are expected to be incurred. CAF Phase II is a multi-year program which requires us to deploy broadband to a specified number of households in each of the states where funding was accepted. Failure to meet our deployment obligations at the end of the program in 2020 will result in a return of a portion of the funding received. We regularly evaluate our ability to meet our broadband deployment obligations and adjust revenue accordingly.  We categorize our products, services and other revenues among the following five categories:   · Data and Internet services include broadband services for consumer and commercial customers. We provide data transmission services to high volume commercial customers and other carriers with dedicated high capacity circuits (“nonswitched access”) including services to wireless providers (“wireless backhaul”);   · Voice services include traditional local and long-distance wireline services, Voice over Internet Protocol (VoIP) services, as well as a number of unified messaging services offered to our consumer and commercial customers. Voice services also include the long-distance voice origination and termination services that we provide to our commercial customers and other carriers;   · Video services include revenues generated from services provided directly to consumer customers through the FiOS ® and Vantage video brands, and through DISH ® satellite TV services;   · Other customer revenue includes sales of customer premise equipment to our commercial customers and directory services, less our provision for bad debts; and   · Switched Access and Subsidy revenues include revenues derived from allowing other carriers to use our network to originate and/or terminate their local and long-distance voice traffic (“switched access”). These services are primarily billed on a minutes-of-use basis applying tariffed rates filed with the FCC or state agencies. We also receive cost subsidies from state and federal authorities, including the Connect America Fund Phase II.  The following table provides a summary of revenues from external customers by the categories of Frontier’s products and services:     For the year ended December 31,  ( $ in millions ) 2017 2016 2015   Data and Internet services $ 3,862 $ 3,693 $ 2,337  Voice services 2,864 2,886 2,022  Video services 1,304 1,244 285  Other 322 276 255  Customer revenue 8,352 8,099 4,899  Switched access and subsidy 776 797 677  Total revenue $ 9,128 $ 8,896 $ 5,576  
Property, Plant and Equipment	(e) Property, Plant and Equipment : Property, plant and equipment are stated at original cost, including capitalized interest, or fair market value as of the date of acquisition for acquired properties. Maintenance and repairs are charged to operating expenses as incurred. The gross book value of routine property, plant and equipment retirements is charged against accumulated depreciation. 
Goodwill and Other Intangibles	(f) Goodwill and Other Intangibles : Goodwill represents the excess of purchase price over the fair value of identifiable tangible and intangible net assets acquired. We undertake studies to determine the fair values of assets and liabilities acquired and allocate purchase prices to assets and liabilities, including property, plant and equipment, goodwill and other identifiable intangibles. We examine the carrying value of our goodwill and trade name annually as of December 31, or more frequently, as circumstances warrant, to determine whether there are any impairment losses. We test for goodwill impairment at the “operating segment” level, as that term is defined in GAAP.  We determined that we have one operating segment based on a number of factors that our management uses to evaluate and run our business operations, including similarities of customers, products and technology. We tested goodwill for impairment as of December 31, 2017 as a result of the continued decline in share price of our common stock since September 30, 2017, the date of our last goodwill impairment test. Refer to Note 6 for a discussion of our goodwill impairment testing and results as of December 31, 2017. As stated in Note 2, we early adopted ASU No. 2017-04, “Simplifying the Test for Goodwill Impairment” during 2017 in conjunction with our goodwill impairment assessment.  Frontier amortizes finite-lived intangible assets over their estimated useful lives on the accelerated method of sum of the years digits. We review such intangible assets at least annually as of December 31 to assess whether any potential impairment exists and whether factors exist that would necessitate a change in useful life and a different amortization period.
Impairment of Long-Lived Assets and Long-Lived Assets to Be Disposed Of	(g) Impairment of Long-Lived Assets and Long-Lived Assets to Be Disposed Of : We review long-lived assets to be held and used, including customer lists, and long-lived assets to be disposed of for impairment whenever events or changes in circumstances indicate that the carrying amount of such assets may not be recoverable. Recoverability of assets to be held and used is measured by comparing the carrying amount of the asset to the future undiscounted net cash flows expected to be generated by the asset. Recoverability of assets held for sale is measured by comparing the carrying amount of the assets to their estimated fair market value. If any assets are considered to be impaired, the impairment is measured by the amount by which the carrying amount of the assets exceeds the estimated fair value. Also, we periodically reassess the useful lives of our tangible and intangible assets to determine whether any changes are required.
Income Taxes and Deferred Income Taxes	(h) Income Taxes and Deferred Income Taxes : We file a consolidated federal income tax return. We utilize the asset and liability method of accounting for income taxes. Under the asset and liability method, deferred income taxes are recorded for the tax effect of temporary differences between the financial statement basis and the tax basis of assets and liabilities using tax rates expected to be in effect when the temporary differences are expected to reverse.
Stock Plans	(i) Stock Plans : We have various stock-based compensation plans. Awards under these plans are granted to eligible employees and directors. Awards may be made in the form of incentive stock options, non-qualified stock options, stock appreciation rights, restricted stock, restricted stock units or other stock-based awards, including awards with performance, market and time-vesting conditions. Our general policy is to issue shares from treasury upon the grant of restricted shares, earning of performance shares and the exercise of options.  The compensation cost recognized is based on awards ultimately expected to vest. GAAP requires forfeitures to be estimated and revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates.
Net Loss Per Share Attributable to Frontier Common Shareholders	Net Loss Per Share Attributable to Frontier Common Shareholders : Basic net loss per common share is computed using the weighted average number of common shares outstanding during the period being reported on, excluding unvested restricted stock awards. The impact of dividends paid on unvested restricted stock awards have been deducted in the determination of basic and diluted net income (loss) per share attributable to Frontier common shareholders. Except when the effect would be antidilutive, diluted net income per common share reflects the dilutive effect of certain common stock equivalents, as described further in Note 13 – Net Loss Per Common Share.

Description Of Business And S28

Description Of Business And Summary Of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2017
Description Of Business And Summary Of Significant Accounting Policies [Abstract]
Schedule Of Revenue From External Customers	   For the year ended December 31,  ( $ in millions ) 2017 2016 2015   Data and Internet services $ 3,862 $ 3,693 $ 2,337  Voice services 2,864 2,886 2,022  Video services 1,304 1,244 285  Other 322 276 255  Customer revenue 8,352 8,099 4,899  Switched access and subsidy 776 797 677  Total revenue $ 9,128 $ 8,896 $ 5,576  

Acquisitions (Tables)

Acquisitions (Tables)	12 Months Ended
	Dec. 31, 2017
Business Acquisition [Line Items]
Schedule Of Acquisition And Integration Costs	   For the year ended December 31,  ($ in millions) 2017 2016 2015   Acquisition costs:  CTF Acquisition $ - $ 23 $ 44  Connecticut Acquisition - - 1  - 23 45  Integration costs:  CTF Acquisition 25 412 152  Connecticut Acquisition - 1 39  25 413 191  Total acquisition and  integration costs $ 25 $ 436 $ 236  
CTF Transaction [Member]
Business Acquisition [Line Items]
Schedule Of Purchase Price Allocation	   ($ in millions)   Current assets $ 353  Property, plant & equipment 6,096  Goodwill 2,606  Other intangibles - primarily customer base 2,262  Current liabilities (579)  Long-term debt (544)  Other liabilities (323)  Total net assets acquired $ 9,871  
Unaudited Pro Forma Information	   (Unaudited)  For the year ended December 31,  ($ in millions, except per share amounts) 2016 2015   Revenue $ 10,255 $ 11,157   Operating income $ 1,433 $ 1,529   Net loss attributable to Frontier  common shareholders $ (262) $ (192)   Basic and diluted net loss per  share attributable to Frontier  common shareholders $ (3.38) $ (2.66)  

Accounts Receivable (Tables)

Accounts Receivable (Tables)	12 Months Ended
	Dec. 31, 2017
Accounts Receivable [Abstract]
Accounts Receivable	   ($ in millions) 2017 2016   Retail and Wholesale $ 801 $ 979  Other 87 90  Less: Allowance for doubtful accounts (69) (131)  Accounts receivable, net $ 819 $ 938 
Schedule Of Allowance For Doubtful Accounts	   ( $ in millions ) Balance at beginning of Period Charged to Other Revenue Charged (Credited) to Switched and Nonswitched Revenue and Other Accounts Write-offs, net of Recoveries Balance at end of Period   2015 $ 72 $ 67 $ (17) $ (65) $ 57  2016 $ 57 $ 164 $ 15 $ (105) $ 131  2017 $ 131 $ 109 $ (22) $ (149) $ 69  

Property, Plant And Equipment (

Property, Plant And Equipment (Tables)	12 Months Ended
	Dec. 31, 2017
Property, Plant And Equipment [Abstract]
Property, Plant And Equipment, Net	   ($ in millions) Estimated Useful Lives 2017 2016   Land N/A $ 231 $ 235  Buildings and leasehold improvements 41 years 2,282 2,320  General support 5 to 17 years 1,570 1,502  Central office/electronic circuit equipment 5 to 18 years 8,137 7,683  Poles 30 years 1,095 995  Cable, fiber and wire 15 to 25 years 10,997 10,292  Conduit 55 years 1,646 1,611  Construction work in progress 538 903  Property, plant and equipment 26,496 25,541  Less: Accumulated depreciation (12,119) (10,639)  Property, plant and equipment, net $ 14,377 $ 14,902 
Schedule Of Depreciation Expense	   For the Year Ended  ($ in millions) 2017 2016 2015   Depreciation expense $ 1,485 $ 1,388 $ 983  

Goodwill And Other Intangibles

Goodwill And Other Intangibles (Tables)	12 Months Ended
	Dec. 31, 2017
Goodwill And Other Intangibles [Abstract]
Schedule Of Goodwill Activity	   ($ in millions) Goodwill   Balance at January 1, 2016 $ 7,166  CTF Acquisition (Note 3) 2,508  Balance at December 31, 2016 9,674  CTF Acquisition adjustment 98  Goodwill impairment (2,748)  Balance at December 31, 2017 $ 7,024  
Components Of Other Intangibles	   2017 2016  ($ in millions) Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount   Other Intangibles:  Customer base $ 5,188 $ (3,294) $ 1,894 $ 5,088 $ (2,604) $ 2,484  Trade name 122 - 122 122 - 122  Royalty agreement 72 (25) 47 72 (16) 56  Total other intangibles $ 5,382 $ (3,319) $ 2,063 $ 5,282 $ (2,620) $ 2,662 
Schedule Of Amortization Expense	  For the Year Ended  ($ in millions) 2017 2016 2015   Amortization expense $ 699 $ 643 $ 337  

Long-Term Debt (Tables)

Long-Term Debt (Tables)	12 Months Ended
	Dec. 31, 2017
Long-Term Debt [Abstract]
Long-Term Debt	      Year ended December 31, 2017  ($ in millions) January 1, 2017 Payments and Retirements New Borrowings December 31, 2017 Interest Rate at December 31, 2017*   Senior & Subsidiary  Unsecured Debt $ 15,900 $ (1,655) $ - $ 14,245 9.22%  Senior Secured Debt 2,151 (155) 1,500 3,496 5.24%  Secured Subsidiary Debt 100 - - 100 8.50%  Secured Debt 19 (3) - 16 5.56%  Rural Utilities Service Loan Contracts 8 (1) - 7 6.15%  Total Debt $ 18,178 $ (1,814) $ 1,500 $ 17,863 8.44%   Less: Debt Issuance Costs (209) (183)  Less: Debt Premium (Discount) (46) (54)  Less: Current Portion (363) (656)  Total Long-Term Debt $ 17,560 $ 16,970   * Interest rate includes amortization of debt issuance costs and debt premiums or discounts. The interest rates at December 31, 2017 represent a weighted average of multiple issuances . 
Schedule Of Debt	    2017 2016   Principal Interest Principal Interest  ($ in millions) Outstanding Rate Outstanding Rate   Senior Unsecured Debt Due:  4/15/2017 $ - 8.250% $ 210 8.250%  10/1/2018 491 8.125% 583 8.125%  3/15/2019 404 7.125% 434 7.125%  4/15/2020 619 8.500% 1,169 8.500%  9/15/2020 303 8.875% 1,066 8.875%  7/1/2021 490 9.250% 500 9.250%  9/15/2021 775 6.250% 775 6.250%  4/15/2022 500 8.750% 500 8.750%  9/15/2022 2,188 10.500% 2,188 10.500%  1/15/2023 850 7.125% 850 7.125%  4/15/2024 750 7.625% 750 7.625%  1/15/2025 775 6.875% 775 6.875%  9/15/2025 3,600 11.000% 3,600 11.000%  11/1/2025 138 7.000% 138 7.000%  8/15/2026 2 6.800% 2 6.800%  1/15/2027 346 7.875% 346 7.875%  8/15/2031 945 9.000% 945 9.000%  10/1/2034 1 7.680% 1 7.680%  7/1/2035 125 7.450% 125 7.450%  10/1/2046 193 7.050% 193 7.050%  13,495 15,150   Senior Secured Debt Due:  10/24/2019 (1) 245 5.445% (Variable) 280 4.145% (Variable)  3/31/2021 (2) 1,483 4.320% (Variable) 1,564 3.270% (Variable)  10/12/2021 (3) 276 5.445% (Variable) 307 4.145% (Variable)  6/15/2024 (4) 1,492 5.320% (Variable) -  3,496 2,151   Subsidiary Debentures Due:  5/15/2027 200 6.750% 200 6.750%  2/1/2028 300 6.860% 300 6.860%  2/15/2028 200 6.730% 200 6.730%  10/15/2029 50 8.400% 50 8.400%  11/15/2031 100 8.500% 100 8.500%  850 850   Total $ 17,841 8.1% (5) $ 18,151 8.3% (5)     (1) Represents borrowings under the 2014 CoBank Credit Agreement, as defined below. (2) Represents borrowings under the JPM Credit Agreement Term Loan A, as defined below. (3) Represents borrowings under the 2016 CoBank Credit Agreement, as defined below. (4) Represents borrowings under the JPM Credit Agreement Term Loan B, as defined below. (5) Interest rate represents a weighted average of the stated interest rates of multiple issuances .
Debt Maturities by Year	   Principal  ($ in millions) Payments   2018 $ 656  2019 $ 804  2020 $ 1,132  2021 $ 2,558  2022 $ 2,703  Thereafter $ 10,010  
Schedule Of Future Minimum Lease Obligations	   ($ in millions) Finance Lease Obligations Capital Lease Obligations   Year ending December 31:  2018 $ 9 $ 41  2019 9 29  2020 10 19  2021 10 12  2022 10 9  Thereafter 52 9  Total future payments 100 119  Less: Amounts representing interest (55) (14)  Present value of minimum lease payments $ 45 $ 105  

Restructuring Costs (Tables)

Restructuring Costs (Tables)	12 Months Ended
	Dec. 31, 2017
Restructuring Costs [Abstract]
Changes In Restructuring Reserve	    Restructuring  ($ in millions) Liability  Balance, January 1, 2016 $ 1  Severance costs 65  Cash payments during the period (19)  Balance, December 31, 2016 47  Severance costs 68  Cash payments during the period (90)  Balance, December 31, 2017 $ 25  

Investment and Other Income, 35

Investment and Other Income, Net (Tables)	12 Months Ended
	Dec. 31, 2017
Investment and Other Income, Net [Abstract]
Components Of Investment and Other Income, Net	   ( $ in millions ) 2017 2016 2015   Interest and dividend income $ 6 $ 13 $ 7  Gain on expiration/settlement of customer advances - 13 -  All other, net (3) 1 -  Total investment and other income, net $ 3 $ 27 $ 7  

Stock Plans (Tables)

Stock Plans (Tables)	12 Months Ended
	Dec. 31, 2017
Stock Plans [Abstract]
LTIP Target Performance Shares	   Number of  Shares  (in thousands)  Balance at December 31, 2014 179  LTIP target performance shares granted 49  LTIP target performance shares earned (50)  LTIP target performance shares forfeited (10)  Balance at December 31, 2015 168  LTIP target performance shares granted 111  LTIP target performance shares earned (59)  LTIP target performance shares forfeited (30)  Balance at December 31, 2016 190  LTIP target performance shares granted 211  LTIP target performance shares earned (41)  LTIP target performance shares forfeited (54)  Balance at December 31, 2017 306  
Restricted Shares Outstanding	   Weighted  Average  Number of Grant Date Aggregate  Shares Fair Value Fair Value  (in thousands) (per share) (in millions)  Balance at December 31, 2014 512 $ 71.25 $ 52  Restricted stock granted 188 $ 118.80 $ 13  Restricted stock vested (214) $ 73.35 $ 15  Restricted stock forfeited (24) $ 76.50  Balance at December 31, 2015 462 $ 88.95 $ 33  Restricted stock granted 396 $ 65.40 $ 20  Restricted stock vested (248) $ 78.90 $ 13  Restricted stock forfeited (61) $ 76.65  Balance at December 31, 2016 549 $ 78.00 $ 28  Restricted stock granted 454 $ 47.77 $ 3  Restricted stock vested (240) $ 80.86 $ 2  Restricted stock forfeited (130) $ 60.92  Balance at December 31, 2017 633 $ 58.63 $ 4  

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2017
Income Taxes [Abstract]
Reconciliation Of Provision For Income Taxes	   2017 2016 2015   Consolidated tax provision at federal statutory rate 35.0 % 35.0 % 35.0 %  State income tax provisions, net of federal income  tax benefit 1.7 (0.1) 8.7  Tax reserve adjustment 0.1 0.6 (0.3)  Domestic production activities deduction - (1.9) -  Changes in certain deferred tax balances (0.4) 5.8 0.8  Goodwill impairment (19.1) - -  Federal research and development credit 0.1 1.0 1.5  Non-deductible transaction costs - - 0.4  Deferred Tax Remeasurement - 2017 Tax Reform 26.1 - -  All other, net (0.1) (0.2) (0.3)  Effective tax rate 43.4 % 40.2 % 45.8 % 
Components of Net Deferred Income Tax Liability (Asset)	   ( $ in millions ) 2017 2016   Deferred income tax liabilities:  Property, plant and equipment basis differences $ 2,022 $ 2,751  Intangibles 140 878  Deferred revenue/expense 8 14  Other, net 4 12  $ 2,174 $ 3,655   Deferred income tax assets:  Pension liability 176 273  Tax operating loss carryforward 960 687  Employee benefits 192 255  Accrued expenses 23 44  Lease obligations 39 75  Tax credit 43 30  Allowance for doubtful accounts 7 44  Other, net 2 2  1,442 1,410  Less: Valuation allowance (407) (271)  Net deferred income tax asset 1,035 1,139  Net deferred income tax liability $ 1,139 $ 2,516   
Schedule of Components of Income Tax Expense (Benefit)	    ( $ in millions ) 2017 2016 2015   Income tax expense (benefit):  Current:  Federal $ (4) $ (52) $ 8  State 5 7 (6)  Total Current 1 (45) 2   Deferred:  Federal (1,312) (145) (126)  State (72) (60) (41)  Total Deferred (1,384) (205) (167)  Total income tax expense (benefit) (1,383) (250) (165)   Income taxes charged (credited) to equity of Frontier:  Utilization of the benefits arising from restricted stock (1) (5) -  Deferred income taxes (benefits) arising from the recognition  of additional pension/OPEB liability 7 (21) 36   Total income taxes charged (credited) to equity of Frontier 6 (26) 36  Total income taxes $ (1,377) $ (276) $ (129)  
Changes in the Balance of Unrecognized Tax Benefits	   ($ in millions) 2017 2016   Unrecognized tax benefits - beginning of year $ 16 $ 19  Gross increases - prior year tax positions - 3  Gross increases - current year tax positions 3 3  Gross decreases - FIN 48 liability release (7) (9)  Gross decreases - expired statute of limitations - -  Unrecognized tax benefits - end of year $ 12 $ 16  

Net Loss Per Common Share (Tabl

Net Loss Per Common Share (Tables)	12 Months Ended
	Dec. 31, 2017
Net Loss Per Common Share [Abstract]
Calculation Of Net Income (Loss) Per Common Share	    ( $ in millions and shares in thousands, except per share amounts ) 2017 2016 2015   Net loss used for basic and diluted earnings (loss)  per share:  Net loss attributable to Frontier common shareholders $ (2,018) $ (587) $ (316)  Less: Dividends paid on unvested restricted stock awards (2) (3) (3)  Total basic net loss attributable to Frontier  common shareholders $ (2,020) $ (590) $ (319)   Effect of loss related to dilutive stock units - - -  Total diluted net loss attributable to Frontier  common shareholders $ (2,020) $ (590) $ (319)   Basic earnings (loss) per share:  Total weighted average shares and unvested restricted stock  awards outstanding - basic 78,409 78,142 72,787  Less: Weighted average unvested restricted stock awards (673) (535) (479)  Total weighted average shares outstanding - basic 77,736 77,607 72,308   Basic net loss per share attributable to Frontier  common shareholders $ (25.99) $ (7.61) $ (4.41)   Diluted earnings (loss) per share:  Total weighted average shares outstanding - basic 77,736 77,607 72,308  Effect of dilutive shares - - -  Total weighted average shares outstanding - diluted 77,736 77,607 72,308   Diluted net loss per share attributable to Frontier  common shareholders $ (25.99) $ (7.61) $ (4.41)  

Comprehensive Loss (Tables)

Comprehensive Loss (Tables)	12 Months Ended
	Dec. 31, 2017
Comprehensive Loss [Abstract]
Accumulated Other Comprehensive Loss, Net of Tax	   ($ in millions) Pension Costs OPEB Costs Total  Balance at December 31, 2014 (a) $ (330) $ (74) $ (404)  Other comprehensive income (loss) before reclassifications (51) 82 31  Amounts reclassified from accumulated other comprehensive income (loss) 18 2 20  Net current-period other comprehensive income (loss) (33) 84 51  Balance at December 31, 2015 (a) (363) 10 (353)  Other comprehensive income (loss) before reclassifications (65) 11 (54)  Amounts reclassified from accumulated other comprehensive income (loss) 25 (5) 20  Net current-period other comprehensive income (loss) (40) 6 (34)  Balance at December 31, 2016 (a) (403) 16 (387)  Other comprehensive income (loss) before reclassifications (12) (31) (43)  Amounts reclassified from accumulated other comprehensive income (loss) 70 (6) 64  Net current-period other comprehensive income (loss) 58 (37) 21  Balance at December 31, 2017 (a) $ (345) $ (21) $ (366)    (a) Pension and OPEB amounts are net of deferred tax balances of $223 million, $231 million, $211 million, and $247 million as of December 31, 2017, 2016, 2015, and 2014, respectively
Reclassification Out of Accumulated Other Comprehensive Income	     Amount Reclassified from  ($ in millions) Accumulated Other Comprehensive Loss (a)   Details about Accumulated Other Comprehensive Loss Components 2017 2016 2015 Affected Line Item in the Statement Where Net loss is Presented   Amortization of Pension Cost Items (b)  Actuarial gains (losses) $ (30) $ (40) $ (29)  Pension settlement costs (83) - -  Reclassifications, pretax (113) (40) (29) loss before income taxes  Tax Impact 43 15 11 Income tax (expense) benefit  Reclassifications, net of tax $ (70) $ (25) $ (18) Net loss   Amortization of OPEB Cost Items (b)  Prior-service credits/(costs) $ 9 $ 9 $ 5  Actuarial gains (losses) - (1) (8)  Reclassifications, pretax 9 8 (3) loss before income taxes  Tax impact (3) (3) 1 Income tax (expense) benefit  Reclassifications, net of tax $ 6 $ 5 $ (2) Net loss      (a) Amounts in parentheses indicate losses. (b) These accumulated other comprehensive loss components are included in the computation of net periodic pension and OPEB costs (see Note 17 - Retirement Plans for additional details )

Quarterly Financial Data (Table

Quarterly Financial Data (Tables)	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Data [Abstract]
Quarterly Financial Information	  ($ in millions, except per share amounts) First Quarter Second Quarter Third Quarter Fourth Quarter Total Year  2017   Revenue $ 2,356 $ 2,304 $ 2,251 $ 2,217 $ 9,128   Operating income (loss) 271 (394) 309 (1,754) (1,568)   Net loss attributable to Frontier  common shareholders (1) (2) (129) (715) (92) (1,082) (2,018)   Basic net loss per share attributable  to Frontier common shareholders (1) (2) $ (1.67) $ (9.20) $ (1.19) $ (13.91) $ (25.99)   Diluted net loss per share attributable  to Frontier common shareholders (1) (2) $ (1.67) $ (9.21) $ (1.19) $ (13.91) $ (25.99)  (1) During the fourth quarter of 2017, we recorded a goodwill impairment charge of $2,078 million ( $1,822 million after-tax). Refer to Note 6 for further details. (2) The quarterly net loss per share amounts are rounded to the nearest cent. Annual net loss per share may vary depending on the effect of such rounding.        ($ in millions, except per share amounts) First Quarter Second Quarter Third Quarter Fourth Quarter Total Year   2016   Revenue $ 1,355 $ 2,608 $ 2,524 $ 2,409 $ 8,896   Operating income 58 311 264 255 888   Net loss attributable to Frontier  common shareholders (1) (2) (4) (240) (80) (134) (133) (587)   Basic net loss per share attributable  to Frontier common shareholders (1) (2) (3) (4) $ (3.10) $ (1.05) $ (1.73) $ (1.73) $ (7.61)   Diluted net loss per share attributable  to Frontier common shareholders (1) (2) (3) (4) $ (3.10) $ (1.05) $ (1.73) $ (1.73) $ (7.61)    (1) During the fourth quarter of 2016, we recorded acquisition and integration expenses of $49 million ( $48 million after-tax) related to the CTF acquisition in June 2016. (2) During the fourth quarter of 201 6 , we recorded restructuring costs and other charges of $80 million ( $52 million after-tax) related to severance expense and special termination benefits resulting from a reduction in the workforce. (3) The quarterly net loss per share amounts are rounded to the nearest cent. Annual net loss per share may vary depending on the effect of such rounding. The change in revenue, operating income, net loss, and net loss per share during the second quarter of 2016 and each subsequent quarter of 2016 reflects additional results of the CTF Operations related to the CTF Acquisition, as described further in Note 3.

Retirement Plans (Tables)

Retirement Plans (Tables)	12 Months Ended
	Dec. 31, 2017
Retirement Plans [Abstract]
Projected Benefit Obligations, Fair Values of Plan Assets and Amounts Recognized in the Balance Sheet	   ( $ in millions ) 2017 2016   Change in projected benefit obligation (PBO)  PBO at beginning of year $ 3,465 $ 2,142  Service cost 97 88  Interest cost 127 122  Actuarial (gain)/loss 214 137  Benefits paid (59) (155)  CTF Acquisition PBO - 1,108  Settlements (486) -  Special termination benefits 5 23  PBO at end of year $ 3,363 $ 3,465   Change in plan assets  Fair value of plan assets at beginning of year $ 2,766 $ 1,572  Fair value of plan assets for the CTF operations as of acquisition date - 1,120  Actual return on plan assets 378 201  Employer contributions 206 28  Settlements (486) -  Differential payment received from Verizon (131) -  Benefits paid (59) (155)  Fair value of plan assets at end of year $ 2,674 $ 2,766   Funded status $ (689) $ (699)   Amounts recognized in the consolidated balance sheet  Pension and other postretirement benefits - current $ - $ -  Pension and other postretirement benefits - noncurrent $ (689) $ (699)  Accumulated other comprehensive loss $ 556 $ 647  
Net Periodic Benefit Cost	   ( $ in millions ) 2017 2016 2015   Components of total pension benefit cost  Service cost $ 97 $ 88 $ 55  Interest cost on projected benefit obligation 127 122 88  Expected return on plan assets (186) (168) (129)  Amortization of unrecognized loss 30 40 29  Net periodic pension benefit cost 68 82 43  Pension settlement costs 83 - -  Special termination benefits 5 23 -  Total pension benefit cost $ 156 $ 105 $ 43  
Weighted Average Asset Allocations, By Asset Category	   2017 2016  Asset category:  Equity securities 50 % 50 %  Debt securities 40 % 38 %  Alternative investments 10 % 11 %  Cash and other - % 1 %  Total 100 % 100 %  
Expected Benefit Payments Over The Next Ten Years	   ($ in millions) Amount   2018 $ 265  2019 256  2020 251  2021 245  2022 237  2023-2027 1,122  Total $ 2,376  
Schedule of Assumptions Used	   2017 2016 2015  Discount rate - used at year end to value obligation 3.70 % 4.10 % 4.50 %  Discount rate - used to compute annual cost 4.10 % 4.50 % 4.10 %  Expected long-term rate of return on plan assets 7.50 % 7.50 % 7.75 %  Rate of increase in compensation levels 2.50 % 2.50 % 2.50 %  
Schedule of Changes in Projected benefit Obligations for OPEB	   ( $ in millions) 2017 2016   Change in benefit obligation  Benefit obligation at beginning of year $ 925 $ 626  CTF Acquisition PBO - 276  Service cost 21 19  Interest cost 40 37  Plan participants' contributions 7 5  Actuarial (gain)/loss 54 (18)  Benefits paid (31) (23)  Special termination benefits - 3  Benefit obligation at end of year $ 1,016 $ 925   Change in plan assets  Fair value of plan assets at beginning of year $ - $ -  Plan participants' contributions 7 5  Employer contribution 24 18  Benefits paid (31) (23)  Fair value of plan assets at end of year $ - $ -   Funded status $ (1,016) $ (925)   Amounts recognized in the consolidated balance sheet  Pension and other postretirement benefits - current $ (29) $ (23)  Pension and other postretirement benefits - noncurrent $ (987) $ (902)  Accumulated other comprehensive (gain)/loss $ 33 $ (29)  
Schedule of Net Benefit Costs For OPEB	  ( $ in millions ) 2017 2016 2015   Components of total postretirement benefit cost  Service cost $ 21 $ 19 $ 19  Interest cost on projected benefit obligation 40 37 30  Amortization of prior service (credit)/costs (9) (9) (5)  Amortization of unrecognized loss - 1 8  Net periodic postretirement benefit cost 52 48 52  Special termination benefits - 3 -  Total postretirement benefit cost $ 52 $ 51 $ 52  
Schedule of Assumptions Used for OPEB	   2017 2016 2015  Discount rate - used at year end to value obligation 3.70% - 3.80% 4.10% - 4.30% 4.50% - 4.70%  Discount rate - used to compute annual cost 4.10% - 4.30% 4.50% - 4.70% 4.10% - 4.20%  
Schedule of Expected Benefit Payments for OPEB	   ($ in millions) Gross Benefit Medicare Part D Subsidy Total   2018 $ 30 $ - $ 30  2019 37 - 37  2020 44 - 44  2021 49 - 49  2022 52 - 52  2023-2027 306 2 308  Total $ 518 $ 2 $ 520  
Net Periodic Benefit Cost Not Yet Recognized	   Pension Plan OPEB  ( $ in millions ) 2017 2016 2017 2016  Net actuarial loss $ 556 $ 647 $ 54 $ 1  Prior service cost/(credit) - - (21) (30)  Total $ 556 $ 647 $ 33 $ (29)  
Amounts Recognized As A Componenet Of AOCI	   Pension Plan OPEB  ( $ in millions ) 2017 2016 2017 2016  Accumulated other comprehensive (gain)/loss at  beginning of year $ 647 $ 584 $ (29) $ (20)   Net actuarial gain/(loss) recognized during year (30) (40) - (1)  Prior service (cost)/credit recognized during year - - 9 9  Net actuarial loss/(gain) occurring during year 22 103 53 (17)  Settlement loss recognized (83) - - -  Net amount recognized in comprehensive income  (loss) for the year (91) 63 62 (9)  Accumulated other comprehensive (gain)/loss at  end of year $ 556 $ 647 $ 33 $ (29)  

Fair Value Of Financial Instr42

Fair Value Of Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2017
Fair Value Of Financial Instruments [Abstract]
Pension Plan Assets Measured At Fair Value on Recurring Basis	   Fair Value Measurements at December 31, 2017  ( $ in millions ) Total Level 1 Level 2 Level 3  Cash and Cash Equivalents $ 37 $ 37 $ - $ -  U.S. Government Obligations 30 - 30 -  Corporate and Other Obligations 448 - 448 -  Common Stock 523 523 - -  Common/Collective Trusts 1,215 - 1,215 -  Interest in Registered Investment Companies 324 324 - -  Interest in Limited Partnerships and  Limited Liability Companies 115 - - 115  Total investments at fair value $ 2,692 $ 884 $ 1,693 $ 115  Interest and Dividend Receivable 6  Due from Broker for Securities Sold 40  Receivable Associated with Insurance Contract 7  Due to Broker for Securities Purchased (71)  Total Plan Assets, at Fair Value $ 2,674        Fair Value Measurements at December 31, 2016  ( $ in millions ) Total Level 1 Level 2 Level 3  Cash and Cash Equivalents $ 42 $ 42 $ - $ -  U.S. Government Obligations 29 - 29 -  Corporate and Other Obligations 400 - 400 -  Common Stock 487 487 - -  Common/Collective Trusts 1,104 - 1,104 -  Interest in Registered Investment Companies 334 334 - -  Interest in Limited Partnerships and  Limited Liability Companies 118 - - 118  Total investments at fair value $ 2,514 $ 863 $ 1,533 $ 118  Receivable for plan assets of the CTF Operations 258  Interest and Dividend Receivable 6  Due from Broker for Securities Sold 27  Receivable Associated with Insurance Contract 7  Due to Broker for Securities Purchased (46)  Total Plan Assets, at Fair Value $ 2,766  
Changes in Fair Value of Plan's Level 3 Assets	   Interest in Limited Partnerships and Limited Liability Companies  ( $ in millions ) 2017 2016  Balance, beginning of year $ 118 $ 92  Realized gains 12 7  Unrealized gains/(losses) (2) 13  Purchases - 15  Sales and distributions (13) (9)  Balance, end of year $ 115 $ 118  
Redemption of Plan's Level 3 Investments	    ( $ in millions ) Fair Value Liquidation Period Capitalization Rate  Interest in Limited Partnerships and Limited  Liability Companies (d)   MS IFHF SVP LP Cayman (a) $ 1 5 years N/A  MS IFHF SVP LP Alpha (a) 1 5 years N/A  RII World Timberfund, LLC (b) 5 10 years N/A  426 E Casino Road, LLC (c) 15 N/A 7.00%  100 Comm Drive, LLC (c) 9 N/A 8.00%  100 CTE Drive, LLC (c) 10 N/A 9.50%  6430 Oakbrook Parkway, LLC (c) 26 N/A 7.75%  8001 West Jefferson, LLC (c) 26 N/A 8.75%  1500 MacCorkle Ave SE, LLC (c) 14 N/A 8.50%  400 S. Pike Road West, LLC (c) 1 N/A 8.50%  601 N US 131, LLC (c) 1 N/A 9.50%  9260 E. Stockton Blvd., LLC (c) 6 N/A 7.50%  Total Interest in Limited Partnerships and Limited  Liability Companies $ 115   (a) The partnerships’ investment objective is to seek capital appreciation principally through investing in investment funds managed by third party investment managers who employ a variety of alternative investment strategies. These instruments are subject to certain withdrawal restrictions. The Plan is in the process of liquidating its interest in the partnerships and distributions are expected to be made over the next four years. (b) The fund’s objective is to realize substantial long-term capital appreciation by investing in timberland properties primarily in South America and Australia. This investment is subject to certain withdrawal restrictions. (c) The entity invests in commercial real estate properties that are leased to Frontier. The leases are triple net, whereby Frontier is responsible for all expenses, including but not limited to, insurance, repairs and maintenance and payment of property taxes. (d) All Level 3 investments have the same redemption frequency (through the liquidation of underlying investments) and redemption notice period (none). 
Fair Value Of Long-Term Debt	   2017 2016   Carrying Carrying  ($ in millions) Amount Fair Value Amount Fair Value   Long-term debt $ 16,970 $ 13,994 $ 17,560 $ 17,539 

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2017
Commitments And Contingencies [Abstract]
Future Minimum Rental Commitments for All Long-Term Noncancelable Operating Leases	   ($ in millions) Operating Leases   Year ending December 31:  2018 $ 80  2019 25  2020 29  2021 26  2022 23  Thereafter 388  Total minimum lease payments $ 571  
Future Payments for Obligations under Noncancelable Long Distance Contracts and Service Agreements	   ($ in millions) Amount   Year ending December 31:  2018 $ 37  2019 40  2020 31  2021 7  2022 2  Thereafter 9  Total $ 126  
Outstanding Performance Letters of Credit	   ($ in millions) Amount   CNA Financial Corporation (CNA) $ 49  AIG Insurance 114  Zurich 28  All other 1  Total $ 192  

Description Of Business And S44

Description Of Business And Summary Of Significant Accounting Policies (Narrative) (Details) customer in Millions, $ in Millions	Jul. 10, 2017shares	Dec. 31, 2017USD ($)employeestatesegmentcustomershares	Dec. 31, 2016USD ($)shares	Dec. 31, 2015USD ($)	Jan. 31, 2018USD ($)
Number of customers | customer		4.9
Number of subscribers | customer		3.9
Number of employees | employee		22,700
Number of states of operation | state		29
Reverse stock split, conversion ratio	0.0667
Common stock, shares issued (in shares)	80,000,000	79,532,000	79,532,000
Common stock, shares outstanding (in shares)	79,000,000	78,441,000	78,170,000
Common Stock, Shares Authorized	175,000,000	175,000,000	175,000,000
Reverse Stock Split, Fractional Shares Issued	0
Restricted Cash | $		$ 14
Customer surcharges | $		$ 216	$ 217	$ 151
Number of operating regions | segment		1
Subsequent Event [Member]
Restricted Cash | $					$ 7
Scenario, Previously Reported [Member]
Common stock, shares issued (in shares)			1,193,000,000
Common stock, shares outstanding (in shares)			1,178,000,000
Common Stock, Shares Authorized			1,750,000,000

Description Of Business And S45

Description Of Business And Summary Of Significant Accounting Policies (Schedule Of Revenue From External Customers) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information
Revenues	$ 2,217	$ 2,251	$ 2,304	$ 2,356	$ 2,409	$ 2,524	$ 2,608	$ 1,355	$ 9,128	$ 8,896	$ 5,576
Customer Revenue [Member]
Segment Reporting Information
Revenues									8,352	8,099	4,899
Voice Services [Member]
Segment Reporting Information
Revenues									2,864	2,886	2,022
Data And Internet Services [Member]
Segment Reporting Information
Revenues									3,862	3,693	2,337
Video Services [Member]
Segment Reporting Information
Revenues									1,304	1,244	285
Other Customer Revenues [Member]
Segment Reporting Information
Revenues									322	276	255
Switched Access And Subsidy Revenue [Member]
Segment Reporting Information
Revenues									$ 776	$ 797	$ 677

Recent Accounting Pronounceme46

Recent Accounting Pronouncements (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Income tax expense	$ 1	$ (45)	$ 2
Accounting Standards Update 2016-09 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Income tax expense	1
Adjustment to accumulated deficit	$ 1
Taxes paid on behalf of employees		$ 10	$ 14

Acquisitions (Narrative) (Detai

Acquisitions (Narrative) (Details) item in Millions, $ in Millions	Apr. 01, 2016USD ($)item	Oct. 31, 2016USD ($)	Dec. 31, 2017USD ($)	Sep. 30, 2017USD ($)	Jun. 30, 2017USD ($)	Mar. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Sep. 30, 2016USD ($)	Jun. 30, 2016USD ($)	Mar. 31, 2016USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Business Acquisition, Date of Acquisition [Abstract]
Cash paid for acquisition												$ 9,871
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustments [Abstract]
Purchase accounting adjustments											$ 98
Goodwill, net			$ 7,024				$ 9,674				7,024	9,674	$ 7,166
Revenue			2,217	$ 2,251	$ 2,304	$ 2,356	2,409	$ 2,524	$ 2,608	$ 1,355	9,128	8,896	5,576
Operating income			(1,754)	$ 309	$ (394)	$ 271	255	$ 264	$ 311	$ 58	(1,568)	888	745
Capital Expenditures Integration Activities											34	142	153
CTF Transaction [Member]
Business Acquisition, Date of Acquisition [Abstract]
Acquisition purchase price	$ 10,540
Working Capital And Net Debt Settlement Payments Received		$ 15
Number of video connections acquired | item	1.2
Number of broadband connections acquired | item	2.1
Number of voice connections acquired | item	2.5
Cash paid for acquisition	$ 9,871
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustments [Abstract]
Other intangibles adjustment											100
Other intangibles acquired			2,262				$ 2,162				2,262	2,162
Measurement period adjustments											20
Property and equipment adjustment											(140)
Current liabilities adjustment											61
Purchase accounting adjustments											98
Goodwill, net			$ 2,606								2,606
Revenue												3,622
Operating income												582
Capital Expenditures Integration Activities											$ 34	$ 142	129
Connecticut Transaction [Member]
Business Acquisition, Date of Acquisition [Abstract]
Cash paid for acquisition														$ 2,018
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustments [Abstract]
Capital Expenditures Integration Activities													$ 24

Acquisitions (Schedule Of Purch

Acquisitions (Schedule Of Purchase Price Allocation) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Goodwill, net	$ 7,024	$ 9,674	$ 7,166
CTF Transaction [Member]
Business Acquisition [Line Items]
Current assets	353
Property, plant & equipment	6,096
Goodwill, net	2,606
Other intangibles - primarily customer base	2,262	$ 2,162
Current liabilities	(579)
Long-term debt	(544)
Other liabilities	(323)
Total net assets acquired	$ 9,871

Acquisitions (Unaudited Pro For

Acquisitions (Unaudited Pro Forma Information) (Details) - CTF Transaction [Member] - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Revenue	$ 10,255	$ 11,157
Operating income	1,433	1,529
Net loss attributable to Frontier common shareholders	$ (262)	$ (192)
Basic and diluted net income per share attributable to Frontier common shareholders	$ (3.38)	$ (2.66)

Acquisitions (Schedule Of Acqus

Acquisitions (Schedule Of Acqusition And Integration Costs) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Acquisition costs			$ 23	$ 45
Integration costs		$ 25	413	191
Acquisition and integration costs	$ 49	25	436	236
CTF Transaction [Member]
Business Acquisition [Line Items]
Acquisition costs			23	44
Integration costs		$ 25	412	152
Connecticut Transaction [Member]
Business Acquisition [Line Items]
Acquisition costs				1
Integration costs			$ 1	$ 39

Accounts Receivable (Narrative)

Accounts Receivable (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accounts Receivable [Abstract]
Provision for uncollectible amounts	$ 87	$ 179	$ 50
Recoveries	$ 39

Accounts Receivable (Accounts R

Accounts Receivable (Accounts Receivable) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Accounts Receivable [Abstract]
Retail and Wholesale	$ 801	$ 979
Other	87	90
Less: Allowance for doubtful accounts	(69)	(131)
Accounts receivable, net	$ 819	$ 938

Accounts Receivable (Schedule O

Accounts Receivable (Schedule Of Allowance For Doubtful Accounts) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Valuation and Qualifying Accounts Disclosure [Line Items]
Allowance for Doubtful Accounts, Beginning of Period	$ 131
Allowance for Doubtful Accounts, End of Period	69	$ 131
Allowance for Doubtful Accounts [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Allowance for Doubtful Accounts, Beginning of Period	131	57	$ 72
Charged to Other Revenue	109	164	67
Charged (Credited) to Switched and Nonswitched Revenue and Other Accounts	(22)	15	(17)
Write-offs, net of Recoveries	(149)	(105)	(65)
Allowance for Doubtful Accounts, End of Period	$ 69	$ 131	$ 57

Property, Plant And Equipment54

Property, Plant And Equipment (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Property, Plant And Equipment [Abstract]
Capital Leased Assets, Gross	$ 171	$ 154
Proceeds from sale of property	102
Property subject to leasebacks	97
Sale leasebacks, gains	$ 66
Sale leaseback, deferred gain amortization period	2 years
Sale leaseback, gain recognized	$ 23
Sale leaseback, gain remaining	$ 43

Property, Plant, & Equipment (P

Property, Plant, & Equipment (Property, Plant And Equipment, Net) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 26,496	$ 25,541
Construction work in progress	538	903
Less: Accumulated depreciation	(12,119)	(10,639)
Property, plant and equipment, net	14,377	14,902
Land [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	231	235
Buildings and Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 2,282	2,320
Estimated useful lives	41 years
General Support [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 1,570	1,502
General Support [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	17 years
General Support [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	5 years
Central Office Electronic Circuit Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 8,137	7,683
Central Office Electronic Circuit Equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	18 years
Central Office Electronic Circuit Equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	5 years
Poles [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 1,095	995
Estimated useful lives	30 years
Cable and Wire [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 10,997	10,292
Cable and Wire [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	25 years
Cable and Wire [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	15 years
Conduit [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 1,646	$ 1,611
Estimated useful lives	55 years

Property, Plant, & Equipment (S

Property, Plant, & Equipment (Schedule Of Depreciation Expense) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Depreciation [Abstract]
Depreciation expense	$ 1,485	$ 1,388	$ 983

Goodwill And Other Intangible57

Goodwill And Other Intangibles (Narrative) (Details) $ in Millions	3 Months Ended				12 Months Ended
	Dec. 31, 2017USD ($)	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
Finite-Lived Intangible Assets [Line Items]
Accumulated goodwill impairment charges	$ 2,788				$ 2,788	$ 40
EBITDA multiplier	5.5	5.8	5.8	5.8
Estimated future amortization expense, year 1	$ 569				569
Estimated future amortization expense, year 2	454				454
Estimated future amortization expense, year 3	354				354
Estimated future amortization expense, year 4	260				260
Estimated future amortization expense, year 5	$ 173				$ 173
Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
EBITDA multiplier					4.4
Estimated useful life					8 years
Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
EBITDA multiplier					6.5
Estimated useful life					12 years
Customer Base [Member]
Finite-Lived Intangible Assets [Line Items]
Acquired Finite-lived Intangible Asset, Weighted-Average Period before Renewal or Extension					6 years
Royalty Agreement [Member]
Finite-Lived Intangible Assets [Line Items]
Acquired Finite-lived Intangible Asset, Weighted-Average Period before Renewal or Extension					3 years

Goodwill And Other Intangible58

Goodwill And Other Intangibles (Schedule Of Goodwill Activity) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2017	Dec. 31, 2016
Goodwill And Other Intangibles [Abstract]
Goodwill, Beginning Balance		$ 9,674	$ 7,166
Goodwill, Acquired During the Period			2,508
Goodwill, Purchase Accounting Adjustments		98
Goodwill impairment	$ (2,078)	(2,748)
Goodwill, Ending Balance	$ 7,024	$ 7,024	$ 9,674

Goodwill And Other Intangible59

Goodwill And Other Intangibles (Components Of Other Intangibles) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Intangible Assets [Line Items]
Gross Carrying Amount, Total	$ 5,382	$ 5,282
Accumulated Amortization	(3,319)	(2,620)
Net Carrying Amount	2,063	2,662
Trade Name [Member]
Intangible Assets [Line Items]
Gross Carrying Amount, Indefinite	122	122
Net Carrying Amount	122	122
Customer Base [Member]
Intangible Assets [Line Items]
Gross Carrying Amount, Finite	5,188	5,088
Accumulated Amortization	(3,294)	(2,604)
Net Carrying Amount	1,894	2,484
Royalty Agreement [Member]
Intangible Assets [Line Items]
Gross Carrying Amount, Finite	72	72
Accumulated Amortization	(25)	(16)
Net Carrying Amount	$ 47	$ 56

Goodwill And Other Intangible60

Goodwill And Other Intangibles (Schedule Of Amortization Expense) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Goodwill And Other Intangibles [Abstract]
Amortization expense	$ 699	$ 643	$ 337

Long-Term Debt (Narrative) (Det

Long-Term Debt (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Issue price expressed as a percentage of principal amount (in hundredths)	100.00%
Proceeds from debt, net of issuance costs			$ 6,485,000,000
Loss on early extinguishment of debt	$ (88,000,000)	$ (7,000,000)
Financing obligation for contribution of real property to pension plan		15,000,000
Fair value of property contributed to plan		15,000,000
Pension Building Contribution Aggregate Annual Rent		2,000,000
Lease term of contributed property	15 years
Sale and leaseback term, minimum (in years)	12 years
Sale and leaseback term, maximum (in years)	23 years
Capital Lease Term, minimum years	1 year
Capital Lease Term, maximum years	7 years
2016 Pension Real Estate Contributions [Member]
Debt Instrument [Line Items]
Financing obligation for contribution of real property to pension plan		15,000,000
Letter of Credit [Member]
Debt Instrument [Line Items]
Line of credit facility maximum borrowing capacity	$ 134,000,000
Long-term Line of Credit	$ 63,000,000	0
Senior Notes 7.875% [Member]
Debt Instrument [Line Items]
Interest Rate			7.875%
Payments to retire debt			$ 97,000,000
Senior Notes 6.625% [Member]
Debt Instrument [Line Items]
Interest Rate			6.625%
Payments to retire debt			$ 105,000,000
Senior Note Due 4/15/2017 [Member] | Exchangeable Debt [Member]
Debt Instrument [Line Items]
Debt Conversion, Original Debt, Amount		$ 397,000,000
Interest Rate		8.25%
Senior Note Due 4/15/2020 [Member] | Exchangeable Debt [Member]
Debt Instrument [Line Items]
Debt Conversion, Converted Instrument, Amount		$ 147,000,000
Interest Rate		8.50%
Senior Note Due 9/15/2020 [Member] | Exchangeable Debt [Member]
Debt Instrument [Line Items]
Debt Conversion, Converted Instrument, Amount		$ 66,000,000
Interest Rate		8.875%
Senior Note Due 9/15/2022 [Member] | Exchangeable Debt [Member]
Debt Instrument [Line Items]
Debt Conversion, Converted Instrument, Amount		$ 188,000,000
Interest Rate		10.50%
Secured Equipment Financing [Member]
Debt Instrument [Line Items]
Secured equipment financing			$ 3,000,000
Secured equipment financing term	4 years
CTF Transaction [Member]
Debt Instrument [Line Items]
Long Term Debt Assumed		$ 600,000,000
CTF Transaction [Member] | Subsidiary Senior Note Due 5/15/2027 [Member]
Debt Instrument [Line Items]
Interest Rate		6.75%
Long Term Debt Assumed		$ 200,000,000
CTF Transaction [Member] | Subsidiary Senior Note Due 2/1/2028 [Member]
Debt Instrument [Line Items]
Interest Rate		6.86%
Long Term Debt Assumed		$ 300,000,000
CTF Transaction [Member] | Subsidiary Senior Note Due 11/15/2031 [Member]
Debt Instrument [Line Items]
Interest Rate		8.50%
Long Term Debt Assumed		$ 100,000,000
Senior Unsecured Debt [Member] | Senior Note Due 4/15/2017 [Member]
Debt Instrument [Line Items]
Interest Rate	8.25%	8.25%
Debt instrument, maturity date	Apr. 15, 2017
Payments to retire debt	$ 210,000,000
Senior Unsecured Debt [Member] | Senior Note Due 10/1/2018 [Member]
Debt Instrument [Line Items]
Interest Rate	8.125%	8.125%
Debt instrument, maturity date	Oct. 1, 2018
Payments to retire debt	$ 92,000,000
Senior Unsecured Debt [Member] | Senior Note Due 3/15/2019 [Member]
Debt Instrument [Line Items]
Interest Rate	7.125%	7.125%
Debt instrument, maturity date	Mar. 15, 2019
Payments to retire debt	$ 30,000,000
Senior Unsecured Debt [Member] | Senior Note Due 4/15/2020 [Member]
Debt Instrument [Line Items]
Interest Rate	8.50%	8.50%
Debt instrument, maturity date	Apr. 15, 2020
Payments to retire debt	$ 550,000,000
Senior Unsecured Debt [Member] | Senior Note Due 9/15/2020 [Member]
Debt Instrument [Line Items]
Debt instrument, face amount	$ 1,000,000,000
Interest Rate	8.875%	8.875%
Debt instrument, maturity date	Sep. 15, 2020
Payments to retire debt	$ 763,000,000
Senior Unsecured Debt [Member] | Senior Note Due 7/1/2021 [Member]
Debt Instrument [Line Items]
Interest Rate	9.25%	9.25%
Debt instrument, maturity date	Jul. 1, 2021
Payments to retire debt	$ 10,000,000
Senior Unsecured Debt [Member] | Senior Note Due 9/15/2021 [Member]
Debt Instrument [Line Items]
Interest Rate	6.25%	6.25%
Debt instrument, maturity date	Sep. 15, 2021
Senior Unsecured Debt [Member] | Senior Note Due 9/15/2022 [Member]
Debt Instrument [Line Items]
Debt instrument, face amount	$ 2,000,000,000
Interest Rate	10.50%	10.50%
Debt instrument, maturity date	Sep. 15, 2022
Senior Unsecured Debt [Member] | Senior Note Due 1/15/2025 [Member]
Debt Instrument [Line Items]
Interest Rate	6.875%	6.875%
Debt instrument, maturity date	Jan. 15, 2025
Senior Unsecured Debt [Member] | Senior Note Due 9/15/2025 [Member]
Debt Instrument [Line Items]
Debt instrument, face amount	$ 3,600,000,000
Interest Rate	11.00%	11.00%
Debt instrument, maturity date	Sep. 15, 2025
Senior Unsecured Debt [Member] | CTF Transaction [Member]
Debt Instrument [Line Items]
Debt instrument, face amount	$ 6,600,000,000
Senior Secured Debt [Member] | CoBank Due 10/24/2019 [Member]
Debt Instrument [Line Items]
Interest Rate	5.445%	4.145%
Debt instrument, maturity date	Oct. 24, 2019
Repayment of the outstanding principal balance, quarterly installments amount	$ 9,000,000
Senior Secured Debt [Member] | CoBank Due 10/21/2021 Member
Debt Instrument [Line Items]
Debt instrument, face amount	$ 315,000,000
Interest Rate	5.445%	4.145%
Debt instrument, maturity date	Oct. 12, 2021
Repayment of the outstanding principal balance, quarterly installments amount	$ 8,000,000
Senior Secured Debt [Member] | 2014 And 2016 CoBank Credit Agreements [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Interest Rate Margin	3.875%
Subsidiary Debentures Due [Member] | Subsidiary Senior Note Due 5/15/2027 [Member]
Debt Instrument [Line Items]
Interest Rate	6.75%	6.75%
Debt instrument, maturity date	May 15, 2027
Subsidiary Debentures Due [Member] | Subsidiary Senior Note Due 2/1/2028 [Member]
Debt Instrument [Line Items]
Interest Rate	6.86%	6.86%
Debt instrument, maturity date	Feb. 1, 2028
Subsidiary Debentures Due [Member] | Subsidiary Senior Note Due 11/15/2031 [Member]
Debt Instrument [Line Items]
Interest Rate	8.50%	8.50%
Debt instrument, maturity date	Nov. 15, 2031
JP Morgan Term Loan A [Member] | Senior Secured Debt [Member]
Debt Instrument [Line Items]
Debt instrument, face amount	$ 1,625,000,000
Interest Rate	4.32%	3.27%
Debt instrument, maturity date	Mar. 31, 2021
JP Morgan Term Loan A [Member] | Senior Secured Debt [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Interest Rate Margin	2.75%
JP Morgan Term Loan B [Member] | Senior Secured Debt [Member]
Debt Instrument [Line Items]
Debt instrument, face amount	$ 1,500,000,000
Interest Rate	5.32%
Debt instrument, maturity date	Jun. 15, 2024
JP Morgan Term Loan B [Member] | Senior Secured Debt [Member] | Base Rate [Member]
Debt Instrument [Line Items]
Interest Rate Margin	2.75%
JP Morgan Term Loan B [Member] | Senior Secured Debt [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Interest Rate Margin	3.75%
JP Morgan Revolving Credit Facility 2015 [Member]
Debt Instrument [Line Items]
Debt instrument, maturity date	Feb. 27, 2022
Line of credit facility maximum borrowing capacity	$ 850,000,000
JP Morgan Combined Credit Facility [Member]
Debt Instrument [Line Items]
Amount outstanding before facility can be used to fund dividend payments	$ 250,000,000
Days Prior To Maturity To Meet Threshold To Not Accelerate Debt	91 days
Maximum Debt Threshold To Not Accelerate Debt	$ 500,000,000
Minimum [Member] | Senior Secured Debt [Member] | 2014 And 2016 CoBank Credit Agreements [Member] | Base Rate [Member]
Debt Instrument [Line Items]
Interest Rate Margin	0.875%
Minimum [Member] | Senior Secured Debt [Member] | 2014 And 2016 CoBank Credit Agreements [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Interest Rate Margin	1.875%
Minimum [Member] | JP Morgan Term Loan A And Revolver [Member] | Base Rate [Member]
Debt Instrument [Line Items]
Interest Rate Margin	0.75%
Minimum [Member] | JP Morgan Term Loan A And Revolver [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Interest Rate Margin	1.75%
Maximum [Member] | Senior Secured Debt [Member] | 2014 And 2016 CoBank Credit Agreements [Member] | Base Rate [Member]
Debt Instrument [Line Items]
Interest Rate Margin	3.875%
Maximum [Member] | Senior Secured Debt [Member] | 2014 And 2016 CoBank Credit Agreements [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Interest Rate Margin	4.875%
Maximum [Member] | JP Morgan Term Loan A And Revolver [Member] | Base Rate [Member]
Debt Instrument [Line Items]
Interest Rate Margin	1.75%
Maximum [Member] | JP Morgan Term Loan A And Revolver [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Interest Rate Margin	2.75%

Long-Term Debt (Long-Term Debt)

Long-Term Debt (Long-Term Debt) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Long-term debt, beginning balance	$ 18,178
Payments and Retirements	(1,814)
New Borrowings	1,500
Long-term debt, ending balance	(18,178)	$ (17,863)	$ (18,178)
Less: Debt Issuance Costs		(183)	(209)
Less: Debt Discount/Premium		(54)	(46)
Less: Current Portion		(656)	(363)
Total Long-Term Debt		$ 16,970	17,560
Weighted average interest rate		8.44%
Senior and Subsidiary Unsecured Debt [Member]
Debt Instrument [Line Items]
Long-term debt, beginning balance	15,900
Payments and Retirements	(1,655)
Long-term debt, ending balance	(15,900)	$ (14,245)	(15,900)
Weighted average interest rate		9.22%
Senior Secured Debt [Member]
Debt Instrument [Line Items]
Long-term debt, beginning balance	2,151
Payments and Retirements	(155)
New Borrowings	1,500
Long-term debt, ending balance	(2,151)	$ (3,496)	(2,151)
Weighted average interest rate		5.24%
Secured Subsidiary Debt [Member]
Debt Instrument [Line Items]
Long-term debt, beginning balance	100
Long-term debt, ending balance	(100)	$ (100)	(100)
Weighted average interest rate		8.50%
Secured Debt [Member]
Debt Instrument [Line Items]
Long-term debt, beginning balance	19
Payments and Retirements	(3)
Long-term debt, ending balance	(19)	$ (16)	(19)
Weighted average interest rate		5.56%
Rural Utilities Service Loan Contracts [Member]
Debt Instrument [Line Items]
Long-term debt, beginning balance	8
Payments and Retirements	(1)
Long-term debt, ending balance	$ (8)	$ (7)	$ (8)
Weighted average interest rate		6.15%

Long-Term Debt (Schedule Of Deb

Long-Term Debt (Schedule Of Debt) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Principal Outstanding	$ 17,863	$ 18,178
Senior Unsecured Debt [Member]
Debt Instrument [Line Items]
Principal Outstanding	$ 13,495	15,150
Senior Unsecured Debt [Member] | Senior Note Due 4/15/2017 [Member]
Debt Instrument [Line Items]
Debt instrument, maturity date	Apr. 15, 2017
Principal Outstanding		$ 210
Interest Rate	8.25%	8.25%
Senior Unsecured Debt [Member] | Senior Note Due 10/1/2018 [Member]
Debt Instrument [Line Items]
Debt instrument, maturity date	Oct. 1, 2018
Principal Outstanding	$ 491	$ 583
Interest Rate	8.125%	8.125%
Senior Unsecured Debt [Member] | Senior Note Due 3/15/2019 [Member]
Debt Instrument [Line Items]
Debt instrument, maturity date	Mar. 15, 2019
Principal Outstanding	$ 404	$ 434
Interest Rate	7.125%	7.125%
Senior Unsecured Debt [Member] | Senior Note Due 4/15/2020 [Member]
Debt Instrument [Line Items]
Debt instrument, maturity date	Apr. 15, 2020
Principal Outstanding	$ 619	$ 1,169
Interest Rate	8.50%	8.50%
Senior Unsecured Debt [Member] | Senior Note Due 9/15/2020 [Member]
Debt Instrument [Line Items]
Debt instrument, maturity date	Sep. 15, 2020
Principal Outstanding	$ 303	$ 1,066
Interest Rate	8.875%	8.875%
Senior Unsecured Debt [Member] | Senior Note Due 7/1/2021 [Member]
Debt Instrument [Line Items]
Debt instrument, maturity date	Jul. 1, 2021
Principal Outstanding	$ 490	$ 500
Interest Rate	9.25%	9.25%
Senior Unsecured Debt [Member] | Senior Note Due 9/15/2021 [Member]
Debt Instrument [Line Items]
Debt instrument, maturity date	Sep. 15, 2021
Principal Outstanding	$ 775	$ 775
Interest Rate	6.25%	6.25%
Senior Unsecured Debt [Member] | Senior Note Due 4/15/2022 [Member]
Debt Instrument [Line Items]
Debt instrument, maturity date	Apr. 15, 2022
Principal Outstanding	$ 500	$ 500
Interest Rate	8.75%	8.75%
Senior Unsecured Debt [Member] | Senior Note Due 9/15/2022 [Member]
Debt Instrument [Line Items]
Debt instrument, maturity date	Sep. 15, 2022
Principal Outstanding	$ 2,188	$ 2,188
Interest Rate	10.50%	10.50%
Senior Unsecured Debt [Member] | Senior Note Due 1/15/2023 [Member]
Debt Instrument [Line Items]
Debt instrument, maturity date	Jan. 15, 2023
Principal Outstanding	$ 850	$ 850
Interest Rate	7.125%	7.125%
Senior Unsecured Debt [Member] | Senior Note Due 4/15/2024 [Member]
Debt Instrument [Line Items]
Debt instrument, maturity date	Apr. 15, 2024
Principal Outstanding	$ 750	$ 750
Interest Rate	7.625%	7.625%
Senior Unsecured Debt [Member] | Senior Note Due 1/15/2025 [Member]
Debt Instrument [Line Items]
Debt instrument, maturity date	Jan. 15, 2025
Principal Outstanding	$ 775	$ 775
Interest Rate	6.875%	6.875%
Senior Unsecured Debt [Member] | Senior Note Due 9/15/2025 [Member]
Debt Instrument [Line Items]
Debt instrument, maturity date	Sep. 15, 2025
Principal Outstanding	$ 3,600	$ 3,600
Interest Rate	11.00%	11.00%
Senior Unsecured Debt [Member] | Senior Note Due 11/1/2025 [Member]
Debt Instrument [Line Items]
Debt instrument, maturity date	Nov. 1, 2025
Principal Outstanding	$ 138	$ 138
Interest Rate	7.00%	7.00%
Senior Unsecured Debt [Member] | Senior Note Due 8/15/2026 [Member]
Debt Instrument [Line Items]
Debt instrument, maturity date	Aug. 15, 2026
Principal Outstanding	$ 2	$ 2
Interest Rate	6.80%	6.80%
Senior Unsecured Debt [Member] | Senior Note Due 1/15/2027 [Member]
Debt Instrument [Line Items]
Debt instrument, maturity date	Jan. 15, 2027
Principal Outstanding	$ 346	$ 346
Interest Rate	7.875%	7.875%
Senior Unsecured Debt [Member] | Senior Note Due 8/15/2031 [Member]
Debt Instrument [Line Items]
Debt instrument, maturity date	Aug. 15, 2031
Principal Outstanding	$ 945	$ 945
Interest Rate	9.00%	9.00%
Senior Unsecured Debt [Member] | Senior Note Due 10/1/2034 [Member]
Debt Instrument [Line Items]
Debt instrument, maturity date	Oct. 1, 2034
Principal Outstanding	$ 1	$ 1
Interest Rate	7.68%	7.68%
Senior Unsecured Debt [Member] | Senior Note Due 7/1/2035 [Member]
Debt Instrument [Line Items]
Debt instrument, maturity date	Jul. 1, 2035
Principal Outstanding	$ 125	$ 125
Interest Rate	7.45%	7.45%
Senior Unsecured Debt [Member] | Senior Note Due 10/1/2046 [Member]
Debt Instrument [Line Items]
Debt instrument, maturity date	Oct. 1, 2046
Principal Outstanding	$ 193	$ 193
Interest Rate	7.05%	7.05%
Senior Secured Debt [Member]
Debt Instrument [Line Items]
Principal Outstanding	$ 3,496	$ 2,151
Senior Secured Debt [Member] | CoBank Due 10/24/2019 [Member]
Debt Instrument [Line Items]
Debt instrument, maturity date	Oct. 24, 2019
Principal Outstanding	$ 245	$ 280
Interest Rate	5.445%	4.145%
Senior Secured Debt [Member] | CoBank Due 10/21/2021 Member
Debt Instrument [Line Items]
Debt instrument, maturity date	Oct. 12, 2021
Principal Outstanding	$ 276	$ 307
Interest Rate	5.445%	4.145%
Subsidiary Debentures Due [Member]
Debt Instrument [Line Items]
Principal Outstanding	$ 850	$ 850
Subsidiary Debentures Due [Member] | Subsidiary Senior Note Due 5/15/2027 [Member]
Debt Instrument [Line Items]
Debt instrument, maturity date	May 15, 2027
Principal Outstanding	$ 200	$ 200
Interest Rate	6.75%	6.75%
Subsidiary Debentures Due [Member] | Subsidiary Senior Note Due 2/1/2028 [Member]
Debt Instrument [Line Items]
Debt instrument, maturity date	Feb. 1, 2028
Principal Outstanding	$ 300	$ 300
Interest Rate	6.86%	6.86%
Subsidiary Debentures Due [Member] | Subsidiary Senior Note Due 2/15/2028 [Member]
Debt Instrument [Line Items]
Debt instrument, maturity date	Feb. 15, 2028
Principal Outstanding	$ 200	$ 200
Interest Rate	6.73%	6.73%
Subsidiary Debentures Due [Member] | Subsidiary Senior Note Due 10/15/2029 [Member]
Debt Instrument [Line Items]
Debt instrument, maturity date	Oct. 15, 2029
Principal Outstanding	$ 50	$ 50
Interest Rate	8.40%	8.40%
Subsidiary Debentures Due [Member] | Subsidiary Senior Note Due 11/15/2031 [Member]
Debt Instrument [Line Items]
Debt instrument, maturity date	Nov. 15, 2031
Principal Outstanding	$ 100	$ 100
Interest Rate	8.50%	8.50%
Senior Secured Debt, Senior Unsecured Debt And Subsidiary Debentures [Member]
Debt Instrument [Line Items]
Principal Outstanding	$ 17,841	$ 18,151
Weighted average interest rate	8.10%	8.30%
JP Morgan Term Loan A [Member] | Senior Secured Debt [Member]
Debt Instrument [Line Items]
Debt instrument, maturity date	Mar. 31, 2021
Principal Outstanding	$ 1,483	$ 1,564
Interest Rate	4.32%	3.27%
JP Morgan Term Loan B [Member] | Senior Secured Debt [Member]
Debt Instrument [Line Items]
Debt instrument, maturity date	Jun. 15, 2024
Principal Outstanding	$ 1,492
Interest Rate	5.32%

Long-Term Debt (Debt Maturities

Long-Term Debt (Debt Maturities By Year) (Details) $ in Millions	Dec. 31, 2017USD ($)
Long-Term Debt [Abstract]
Principal Payments 2018	$ 656
Principal Payments 2019	804
Principal Payments 2020	1,132
Principal Payments 2021	2,558
Principal Payments 2022	2,703
Principal Payments Thereafter	$ 10,010

Long-Term Debt (Schedule Of Fut

Long-Term Debt (Schedule Of Future Minimum Lease Obligations) (Details) $ in Millions	Dec. 31, 2017USD ($)
Finance Lease Obligations, Future Minimum Payments [Abstract]
2,018	$ 9
2,019	9
2,020	10
2,021	10
2,022	10
Thereafter	52
Total future payments	100
Less: Amounts representing interest	(55)
Present value of minimum lease payments	45
Capital Lease Obligations, Future Minimum Payments [Abstract]
2,018	41
2,019	29
2,020	19
2,021	12
2,022	9
Thereafter	9
Total future payments	119
Less: Amounts representing interest	(14)
Present value of minimum lease payments	$ 105

Restructuring Costs (Narrative)

Restructuring Costs (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Restructuring Costs [Abstract]
Restructuring Reserve	$ 47	$ 25	$ 47	$ 1
Severance Costs		68	65
Defined Benefit Plan, Special termination Benefits cost		5	26
Loss on sale of business		9
Restructuring Charges	$ 80	$ 82	$ 91	$ 2

Restructuring Costs (Changes In

Restructuring Costs (Changes In Restructuring Reserve) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Restructuring Costs [Abstract]
Restructuring Reserve, Beginning Balance	$ 47	$ 1
Severance Costs	68	65
Cash payments during the period	(90)	(19)
Restructuring Reserve, Ending Balance	$ 25	$ 47

Investment and Other Income, 68

Investment and Other Income, Net (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Investment and Other Income, Net [Abstract]
Interest and dividend income	$ 6	$ 13	$ 7
Gain on expiration/settlement of customer advances		13
All other, net	(3)	1
Total investment and other income, net	$ 3	$ 27	$ 7

Capital Stock (Narrative) (Deta

Capital Stock (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Jun. 29, 2018	Jul. 10, 2017
Class of Stock [Line Items]
Common Stock, Shares Authorized	175,000,000	175,000,000			175,000,000
Preferred Stock, Shares Authorized	50,000,000	50,000,000
Common stock, par value (in dollars per share)	$ 0.25	$ 0.25
Proceeds from Issuance of Common Stock			$ 799
Preferred Stock, Dividend Rate, Percentage	11.125%	11.125%
Preferred Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Proceeds from Issuance of Preferred Stock and Preference Stock			1,866
Preferred dividends	$ 214	$ 214	$ 120
Scenario, Previously Reported [Member]
Class of Stock [Line Items]
Common Stock, Shares Authorized		1,750,000,000
Common Stock [Member]
Class of Stock [Line Items]
Common stock, par value (in dollars per share)	$ 0.25
Common Stock [Member] | Scenario, Previously Reported [Member]
Class of Stock [Line Items]
Stock Issued During Period Shares Excluding Over Allotment New Issues			150,000,000
Shares Issued, Price Per Share	$ 5
Over Allotment Option Shares Issued	15,000,000
Preferred Stock [Member]
Class of Stock [Line Items]
Stock Issued During Period Shares Excluding Over Allotment New Issues	17,500,000
Shares Issued, Price Per Share	$ 100
Over Allotment Option Shares Issued	1,750,000
Preferred Stock, Dividend Rate, Percentage	11.125%
Preferred Stock, Par or Stated Value Per Share	$ 0.01
Preferred Stock, Liquidation Preference Per Share	$ 100
Restricted cash			$ 1,955
Proceeds from Equity, Net of Issuance Costs			$ 2,665
Minimum [Member] | Preferred Stock [Member] | Scenario, Forecast [Member]
Class of Stock [Line Items]
Convertible Preferred Stock, Shares Issued upon Conversion				1.1348
Maximum [Member] | Preferred Stock [Member] | Scenario, Forecast [Member]
Class of Stock [Line Items]
Convertible Preferred Stock, Shares Issued upon Conversion				1.3333

Stock Plans (Narrative) (Detail

Stock Plans (Narrative) (Details) $ in Millions	Feb. 16, 2017shares	Feb. 11, 2016shares	Feb. 25, 2015shares	Dec. 31, 2017USD ($)ShareBasedCompensationPlanentityshares	Dec. 31, 2016USD ($)shares	Dec. 31, 2015USD ($)shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of stock-based compensation plan under which grants were made | ShareBasedCompensationPlan				7
Number of stock-based compensation plan under which grants were not made | ShareBasedCompensationPlan				6
Shares authorized for grant under the plans (in shares) | shares				5,667,000
Shares available for grant under the plan (in shares) | shares				4,361,000
2017 EIP [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Plan authorization period				10 years
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expense recognized during the period | $				$ 1	$ 6	$ 7
Shares granted (in shares) | shares	157,400	1,669,000	665,000	211,000	111,000	49,000
Performance Shares
Initial period over which target number of performance shares are awarded				90 days
Measurement period				3 years
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expense recognized during the period | $				$ 18	$ 18	$ 20
Shares granted (in shares) | shares				454,000	396,000	188,000
Restricted Stock
Remaining unrecognized compensation cost associated with unvested restricted stock awards | $				$ 21
Weighted average period over which unvested restricted stock awards unrecognized compensation cost is expected to be recognized (in years)				1 year 2 months 12 days
Stock Options [Member] | 2017 EIP [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period				4 years
Non-Employee Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expense recognized during the period | $				$ (5)	$ 0	$ (1)
Non Employee Directors Compensation Plans
Plan units earned during the period (in shares) | shares				94,034	29,618	22,279
Number of directors participating in the plan during the period | entity				9
Cash compensation | $				$ 1	$ 1	$ 1

Stock Plans (LTIP Target Perfor

Stock Plans (LTIP Target Performance Shares) (Details) - Performance Shares [Member] - shares	Feb. 16, 2017	Feb. 11, 2016	Feb. 25, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Balance at beginning of period (in shares)				190,000	168,000	179,000
Shares granted (in shares)	157,400	1,669,000	665,000	211,000	111,000	49,000
Shares vested (in shares)				(41,000)	(59,000)	(50,000)
Shares forfeited (in shares)				(54,000)	(30,000)	(10,000)
Balance at end of period (in shares)				306,000	190,000	168,000

Stock Plans (Restricted Shares

Stock Plans (Restricted Shares Outstanding) (Details) - Restricted Stock [Member] - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Balance at beginning of period (in shares)	549	462	512
Shares granted (in shares)	454	396	188
Shares vested (in shares)	(240)	(248)	(214)
Shares forfeited (in shares)	(130)	(61)	(24)
Balance at end of period (in shares)	633	549	462
Balance at beginning of period (in dollars per shares)	$ 78	$ 88.95	$ 71.25
Restricted stock granted (in dollars per shares)	47.77	65.40	118.80
Restricted stock vested (in dollars per shares)	80.86	78.90	73.35
Restricted stock forfeited (in dollars per shares)	60.92	76.65	76.50
Balance at end of period (in dollars per shares)	$ 58.63	$ 78	$ 88.95
Balance at beginning of period	$ 28	$ 33	$ 52
Restricted stock granted	3	20	13
Restricted stock vested	2	13	15
Balance at end of period	$ 4	$ 28	$ 33

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Contingency [Line Items]
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Impairment Losses, Amount		$ 608
Federal rate		35.00%	35.00%	35.00%
Adjustment of deferred tax balances			$ 36	$ 3
Domestic production activities deduction			12
Federal research and development credits			6	$ 5
Deferred Tax Assets, Valuation Allowance		$ 407	$ 271
Change in tax rate, percent of qualified assets to be expensed		100.00%
Benefit resulting from state law changes		$ 830
Goodwill impairment		19.10%
Effective tax rate		43.40%	40.20%	45.80%
Effect of expiration of statute of limitations during next twelve months		$ 3
Alternative minimum tax credit		3
Gross tax liability for tax positions that may not be sustained under a more likely than not threshold		12
Additional interest recognized on tax liability		1
Accrued interest on tax liability		1	$ 1
Deferred Tax Assets, Net, Current		0	55
Proceeds from Income Tax Refunds		51	$ 120
Scenario, Plan [Member]
Income Tax Contingency [Line Items]
Federal rate	21.00%
Research Tax Credit Carryforward [Member]
Income Tax Contingency [Line Items]
Tax Credit Carryforward, Amount		18
State and Local Jurisdiction [Member]
Income Tax Contingency [Line Items]
Tax Credit Carryforward, Amount		27
Operating loss carryforward		9,000
Internal Revenue Service (IRS) [Member]
Income Tax Contingency [Line Items]
Operating loss carryforward		$ 2,100

Income Taxes (Reconciliation Of

Income Taxes (Reconciliation Of Provision For Income Taxes) (Details)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Taxes [Abstract]
Consolidated tax provision at federal statutory rate	35.00%	35.00%	35.00%
State income tax provisions, net of federal income tax benefit	1.70%	(0.10%)	8.70%
Tax reserve adjustment	0.10%	0.60%	(0.30%)
Domestic production activities deduction		(1.90%)
Changes in certain deferred tax balances	(0.40%)	5.80%	0.80%
Goodwill impairment	(19.10%)
Federal research and development credit	0.10%	1.00%	1.50%
Non-deductible transaction costs			0.40%
Deferred Tax Remeasurement - 2017 Tax Reform	26.10%
All other, net	(0.10%)	(0.20%)	(0.30%)
Effective tax rate	43.40%	40.20%	45.80%

Income Taxes (Components Of Net

Income Taxes (Components Of Net Deferred Income Tax Liability (Asset) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Deferred income tax liabilities [Abstract]
Property, plant and equipment basis differences	$ 2,022	$ 2,751
Intangibles	140	878
Deferred Revenue/Expense	8	14
Other, net	4	12
Gross deferred income tax liability	2,174	3,655
Deferred income tax assets [Abstract]
Pension liability	176	273
Tax operating loss carryforward	960	687
Employee benefits	192	255
Accrued expenses	23	44
Capital Lease Obligations	39	75
Tax Credits	43	30
Allowance for doubtful accounts	7	44
Other, net	2	2
Gross deferred income tax asset	1,442	1,410
Less: Valuation allowance	(407)	(271)
Net deferred income tax asset	1,035	1,139
Net deferred income tax liability	$ 1,139	$ 2,516

Income Taxes (Schedule of Compo

Income Taxes (Schedule of Components of Income Tax Expense (Benefit)) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current [Abstract]
Federal	$ (4)	$ (52)	$ 8
State	5	7	(6)
Total current	1	(45)	2
Deferred [Abstract]
Federal	(1,312)	(145)	(126)
State	(72)	(60)	(41)
Total deferred	(1,384)	(205)	(167)
Income Tax Expense (Benefit), Total	(1,383)	(250)	(165)
Income taxes charged (credited) to equity of Frontier [Abstract]
Utilization of the benefits arising from restricted stock	(1)	(5)
Deferred income taxes (benefits) arising from the recognition of additional pension/OPEB liability	7	(21)	36
Total income taxes charged (credited) to equity of Frontier	6	(26)	36
Total income taxes	$ (1,377)	$ (276)	$ (129)

Income Taxes (Changes In The Ba

Income Taxes (Changes In The Balance Of Unrecognized Tax Benefits) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Income Taxes [Abstract]
Unrecognized tax benefits - beginning of year	$ 16	$ 19
Gross increases - prior year tax positions		3
Gross increases - current year tax positions	3	3
Gross Decreases - FIN 48 Liability Release	(7)	(9)
Unrecognized tax benefits - end of year	$ 12	$ 16

Net Loss Per Common Share (Narr

Net Loss Per Common Share (Narrative) (Details) - shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares excluded from the computation of diluted earnings per share (in shares)	1,334	2,667	3,333
Non-Employee Directors' Deferred Fee Plan and Equity Plan [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares excluded from the computation of diluted earnings per share (in shares)	203,952	125,431	95,812
Preferred Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares excluded from the computation of diluted earnings per share (in shares)	19,250,000	19,250,000

Net Loss Per Common Share (Calc

Net Loss Per Common Share (Calculation Of Net Income (Loss) Per Common Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Net Loss Per Common Share [Abstract]
Net income (loss) attributable to Frontier common shareholders	$ (1,082)	$ (92)	$ (715)	$ (129)	$ (133)	$ (134)	$ (80)	$ (240)	$ (2,018)	$ (587)	$ (316)
Less: Dividends paid on unvested restricted stock awards									(2)	(3)	(3)
Total basic net loss attributable to Frontier common shareholders									(2,020)	(590)	(319)
Effect of loss related to dilutive stock units
Total diluted net loss attributable to Frontier common shareholders									$ (2,020)	$ (590)	$ (319)
Total weighted average shares and unvested restricted stock awards outstanding - basic (in shares)									78,409	78,142	72,787
Less: Weighted average unvested restricted stock awards (in shares)									(673)	(535)	(479)
Total weighted average shares outstanding - basic (in shares)									77,736	77,607	72,308
Basic net income (loss) per share attributable to Frontier common shareholders	$ (13.91)	$ (1.19)	$ (9.20)	$ (1.67)	$ (1.73)	$ (1.73)	$ (1.05)	$ (3.10)	$ (25.99)	$ (7.61)	$ (4.41)
Total weighted average shares outstanding - diluted (in shares)									77,736	77,607	72,308
Diluted net loss per share attributable to Frontier common shareholders	$ (13.91)	$ (1.19)	$ (9.21)	$ (1.67)	$ (1.73)	$ (1.73)	$ (1.05)	$ (3.10)	$ (25.99)	$ (7.61)	$ (4.41)

Comprehensive Loss (Narrative)

Comprehensive Loss (Narrative) (Details) - Pension Benefits [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Apr. 01, 2016	Dec. 31, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Discount rate - used at year end to value obligation (in hundredths)	3.70%	4.10%	4.00%	4.50%
Other comprehensive income (loss) before reclassifications		$ 105
Pension Settlement Cost [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassifications, pretax	$ (83)
Reclassifications, net of tax	$ (51)

Comprehensive Loss (Accumulated

Comprehensive Loss (Accumulated Other Comprehensive Loss, Net of Tax) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning	$ 4,519	$ 5,614	$ 3,658
Net current-period other comprehensive income (loss)	21	(34)	51
Balance, ending	2,274	4,519	5,614
Deferred Taxes On Pension And OPEB Costs [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Deferred tax items	223	231	211	$ 247
Defined Benefit Plans [Member] | Pension Benefits [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning	(403)	(363)	(330)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(12)	(65)	(51)
Amounts reclassified from accumulated other comprehensive loss, net of tax	70	25	18
Net current-period other comprehensive income (loss)	58	(40)	(33)
Balance, ending	(345)	(403)	(363)
Defined Benefit Plans [Member] | Postretirement Costs [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning	16	10	(74)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(31)	11	82
Amounts reclassified from accumulated other comprehensive loss, net of tax	(6)	(5)	2
Net current-period other comprehensive income (loss)	(37)	6	84
Balance, ending	(21)	16	10
Accumulated Other Comprehensive Loss [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning	(387)	(353)	(404)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(43)	(54)	31
Amounts reclassified from accumulated other comprehensive loss, net of tax	64	20	20
Net current-period other comprehensive income (loss)	21	(34)	51
Balance, ending	$ (366)	$ (387)	$ (353)

Comprehensive Loss (Reclassific

Comprehensive Loss (Reclassification Out of AOCI) (Details) - Reclassification out of Accumulated Other Comprehensive Income [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Pension Benefits [Member] | Amortization Of Defined Benefit Cost Items [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassifications, pretax	$ (113)	$ (40)	$ (29)
Tax impact	43	15	11
Reclassifications, net of tax	(70)	(25)	(18)
Pension Benefits [Member] | Actuarial Gains (Losses) [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassifications, pretax	(30)	(40)	(29)
Pension Benefits [Member] | Pension Settlement Cost [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassifications, pretax	(83)
Reclassifications, net of tax	(51)
Postretirement Costs [Member] | Amortization Of Defined Benefit Cost Items [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassifications, pretax	9	8	(3)
Tax impact	(3)	(3)	1
Reclassifications, net of tax	6	5	(2)
Postretirement Costs [Member] | Prior-Service Credits (Costs) [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassifications, pretax	$ 9	9	5
Postretirement Costs [Member] | Actuarial Gains (Losses) [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassifications, pretax		$ (1)	$ (8)

Segment Information (Details)

Segment Information (Details)	12 Months Ended
	Dec. 31, 2017segment
Segment Information [Abstract]
Number of operating regions	1
Number of reportable segments	1

Quarterly Financial Data (Narra

Quarterly Financial Data (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Quarterly Financial Data [Abstract]
Goodwill, Impairment Loss	$ 2,078		$ 2,748
Goodwill, Impairment Loss, Net of Tax	$ 1,822
Restructuring Charges		$ 80	82	$ 91	$ 2
Restructuring Charges, Net of Tax		52
Acquisition and integration costs		49	$ 25	$ 436	$ 236
Acquisition and integration costs, after tax		$ 48

Quarterly Financial Data (Sched

Quarterly Financial Data (Schedule Of Quarterly Financial Data) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Quarterly Financial Data [Abstract]
Revenue	$ 2,217	$ 2,251	$ 2,304	$ 2,356	$ 2,409	$ 2,524	$ 2,608	$ 1,355	$ 9,128	$ 8,896	$ 5,576
Operating income (loss)	(1,754)	309	(394)	271	255	264	311	58	(1,568)	888	745
Net income (loss) attributable to Frontier common shareholders	$ (1,082)	$ (92)	$ (715)	$ (129)	$ (133)	$ (134)	$ (80)	$ (240)	$ (2,018)	$ (587)	$ (316)
Basic net income (loss) per share attributable to Frontier common shareholders	$ (13.91)	$ (1.19)	$ (9.20)	$ (1.67)	$ (1.73)	$ (1.73)	$ (1.05)	$ (3.10)	$ (25.99)	$ (7.61)	$ (4.41)
Diluted net loss per share attributable to Frontier common shareholders	$ (13.91)	$ (1.19)	$ (9.21)	$ (1.67)	$ (1.73)	$ (1.73)	$ (1.05)	$ (3.10)	$ (25.99)	$ (7.61)	$ (4.41)

Retirement Plans (Narrative) (D

Retirement Plans (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Apr. 01, 2016
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Pension settlement costs	$ 83
Capitalization of pension and OPEB expense related to engineering and plant construction	$ 26	$ 25	$ 20
Contribution of Property		15
Defined Benefit Plan, Lease term of contributed property	15 years
Pension Building Contribution Aggregate Annual Rent		2
Plan assets acquired during the period		1,108
Accumulated benefit obligation	$ 3,363	3,465
401(k) savings plan employer contributions	$ 48	$ 48	$ 28
Pension Benefits [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate - used at year end to value obligation (in hundredths)	3.70%	4.10%	4.50%	4.00%
Other comprehensive income (loss) before reclassifications		$ (105)
Expected long-term rate of return on plan assets (in hundredths)	7.50%	7.50%	7.75%
Expected Long Term Rate Of Return On Plan Assets In Future Year In Hundreths	7.50%
Expected amortization of unrecognized loss	$ 26
Defined Benefit Plan, Settlements, Benefit Obligation	486
Defined Benefit Plan, Settlements Benefit obligation threshold	224
Pension settlement costs	83
Contributions to plans	206	$ 28
Contributions to plan, net of differential	$ 75
Employer Cash Contributions		13	$ 62
Defined Benefit Plan, Funded Percentage	80.00%
Differential Payment Received	$ 131
Postretirement Benefits Other Than Pensions (OPEB) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected amortization of prior service credit	9
Expected amortization of unrecognized loss	2
Contributions to plans	$ 24	$ 18
Annual rate of increase in the per-capita cost of covered medical benefits (in hundredths)	6.75%
Annual rate of increase in the per-capita cost of covered medical benefits in 2024 (in hundredths)	5.00%
Effect on total of service and interest cost components, 1 percentage point increase	$ 1
Effect on postretirement benefit obligation, 1 percentage point increase	22
Effect on total of service and interest cost components, 1 percentage point decrease	(1)
Effect on postretirement benefit obligation, 1 percentage point decrease	$ (22)
Postretirement Benefits Other Than Pensions (OPEB) [Member] | Minimum [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate - used at year end to value obligation (in hundredths)	3.70%	4.10%	4.50%
Postretirement Benefits Other Than Pensions (OPEB) [Member] | Maximum [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate - used at year end to value obligation (in hundredths)	3.80%	4.30%	4.70%
2016 Pension Real Estate Contributions [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Contribution of Property		$ 15
Fixed Income Securities [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target asset allocation	40.00%
Equity Securities [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target asset allocation	60.00%

Retirement Plans (Projected Ben

Retirement Plans (Projected Benefit Obligation) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Change in plan assets [Roll Forward]
Fair value of plan assets at beginning of year	$ 2,766
Fair value of plan assets at end of year	2,674	$ 2,766
Amounts recognized in the consolidated balance sheet [Abstract]
Pension and other postretirement benefits - current	(29)	(23)
Pension and other postretirement benefits - noncurrent	(1,676)	(1,602)
Pension Benefits [Member]
Change in projected benefit obligation (PBO) [Roll Forward]
PBO at beginning of year	3,465	2,142
Service cost	97	88	$ 55
Interest cost	127	122	88
Actuarial (gain)/loss	214	137
Benefits paid	(59)	(155)
CTF Acquisition PBO		1,108
Settlements	(486)
Special termination benefits	5	23
PBO at end of year	3,363	3,465	2,142
Change in plan assets [Roll Forward]
Fair value of plan assets at beginning of year	2,766	1,572
Fair value of plan assets acquired		1,120
Actual return on plan assets	378	201
Employer contributions	206	28
Settlements	(486)
Differential payment received from Verizon	(131)
Benefits paid	(59)	(155)
Fair value of plan assets at end of year	2,674	2,766	1,572
Funded status	(689)	(699)
Amounts recognized in the consolidated balance sheet [Abstract]
Pension and other postretirement benefits - noncurrent	(689)	(699)
Accumulated other comprehensive (gain) loss	556	647	584
Postretirement Benefits Other Than Pensions (OPEB) [Member]
Change in projected benefit obligation (PBO) [Roll Forward]
PBO at beginning of year	925	626
Service cost	21	19	19
Interest cost	40	37	30
Plan participants' contributions	7	5
Actuarial (gain)/loss	54	(18)
Benefits paid	(31)	(23)
CTF Acquisition PBO		276
Special termination benefits		3
PBO at end of year	1,016	925	626
Change in plan assets [Roll Forward]
Plan participants' contributions	7	5
Employer contributions	24	18
Benefits paid	(31)	(23)
Funded status	(1,016)	(925)
Amounts recognized in the consolidated balance sheet [Abstract]
Pension and other postretirement benefits - current	(29)	(23)
Pension and other postretirement benefits - noncurrent	(987)	(902)
Accumulated other comprehensive (gain) loss	$ 33	$ (29)	$ (20)

Retirement Plans (Net Periodic

Retirement Plans (Net Periodic Benefit Cost) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Pension settlement costs	$ 83
Special termination benefits	5	$ 26
Pension Benefits [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	97	88	$ 55
Interest cost on projected benefit obligation	127	122	88
Expected return on plan assets	(186)	(168)	(129)
Amortization of unrecognized loss	30	40	29
Net periodic benefit cost	68	82	43
Pension settlement costs	83
Special termination benefits	5	23
Total Disclosed Benefit Cost	156	105	43
Postretirement Benefits Other Than Pensions (OPEB) [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	21	19	19
Interest cost on projected benefit obligation	40	37	30
Amortization of prior service (credit)/costs	(9)	(9)	(5)
Amortization of unrecognized loss		1	8
Net periodic benefit cost	52	48	52
Special termination benefits		3
Total Disclosed Benefit Cost	$ 52	$ 51	$ 52

Retirement Plans (Asset Allocat

Retirement Plans (Asset Allocations) (Details)	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Weighted average asset allocation (in hundreths)	100.00%	100.00%
Equity Securities [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Weighted average asset allocation (in hundreths)	50.00%	50.00%
Debt Securities [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Weighted average asset allocation (in hundreths)	40.00%	38.00%
Alternative Investments [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Weighted average asset allocation (in hundreths)	10.00%	11.00%
Cash and Cash Equivalents [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Weighted average asset allocation (in hundreths)		1.00%

Retirement Plans (Pension Expec

Retirement Plans (Pension Expected Benefit Payments) (Details) - Pension Benefits [Member] $ in Millions	Dec. 31, 2017USD ($)
Defined Benefit Plan, Estimated Future Benefit Payments [Abstract]
2,018	$ 265
2,019	256
2,020	251
2,021	245
2,022	237
2023 - 2027	1,122
Total	$ 2,376

Retirement Plans (Assumptions U

Retirement Plans (Assumptions Used) (Details)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Apr. 01, 2016
Pension Benefits [Member]
Defined Benefit Plan, Assumptions Used in Calculations [Abstract]
Discount rate - used at year end to value obligation (in hundredths)	3.70%	4.10%	4.50%	4.00%
Discount rate - used to compute annual cost (in hundredths)	4.10%	4.50%	4.10%
Expected long-term rate of return on plan assets (in hundredths)	7.50%	7.50%	7.75%
Rate of increase in compensation levels (in hundredths)	2.50%	2.50%	2.50%
Postretirement Benefits Other Than Pensions (OPEB) [Member] | Maximum [Member]
Defined Benefit Plan, Assumptions Used in Calculations [Abstract]
Discount rate - used at year end to value obligation (in hundredths)	3.80%	4.30%	4.70%
Discount rate - used to compute annual cost (in hundredths)	4.30%	4.70%	4.20%
Postretirement Benefits Other Than Pensions (OPEB) [Member] | Minimum [Member]
Defined Benefit Plan, Assumptions Used in Calculations [Abstract]
Discount rate - used at year end to value obligation (in hundredths)	3.70%	4.10%	4.50%
Discount rate - used to compute annual cost (in hundredths)	4.10%	4.50%	4.10%

Retirement Plans (Schedule of E

Retirement Plans (Schedule of Expected Benefit Payments for OPEB) (Details) $ in Millions	Dec. 31, 2017USD ($)
OPEB, Gross Benefits [Member]
Defined Benefit Plan, Estimated Future Benefit Payments [Abstract]
2,018	$ 30
2,019	37
2,020	44
2,021	49
2,022	52
2023 - 2027	306
Total	518
Medicare Part D Subsidy [Member]
Defined Benefit Plan, Estimated Future Benefit Payments [Abstract]
2023 - 2027	2
Total	2
Postretirement Benefits Other Than Pensions (OPEB) [Member]
Defined Benefit Plan, Estimated Future Benefit Payments [Abstract]
2,018	30
2,019	37
2,020	44
2,021	49
2,022	52
2023 - 2027	308
Total	$ 520

Retirement Plans (Net Periodi93

Retirement Plans (Net Periodic Benefit Cost Not Yet Recognized) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Pension Benefits [Member]
Defined Benefit Plan [Abstract]
Net actuarial loss	$ 556	$ 647
Total	556	647	$ 584
Postretirement Benefits Other Than Pensions (OPEB) [Member]
Defined Benefit Plan [Abstract]
Net actuarial loss	54	1
Prior service cost/(credit)	(21)	(30)
Total	$ 33	$ (29)	$ (20)

Retirement Plans (Amounts Recog

Retirement Plans (Amounts Recognized as a Component of AOCI) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Pension Benefits [Member]
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax [Abstract]
Accumulated other comprehensive (gain) loss at beginning of year	$ 647	$ 584
Net actuarial gain/(loss) recognized during year	(30)	(40)
Net actuarial loss/(gain) occuring during year	22	103
Settlement loss recognized	(83)
Net amount recognized in comprehensive income (loss) for the year	(91)	63
Accumulated other comprehensive (gain)/loss at end of year	556	647
Postretirement Benefits Other Than Pensions (OPEB) [Member]
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax [Abstract]
Accumulated other comprehensive (gain) loss at beginning of year	(29)	(20)
Net actuarial gain/(loss) recognized during year		(1)
Prior service (cost)/credit recognized during year	9	9
Net actuarial loss/(gain) occuring during year	53	(17)
Net amount recognized in comprehensive income (loss) for the year	62	(9)
Accumulated other comprehensive (gain)/loss at end of year	$ 33	$ (29)

Fair Value of Financial Instr95

Fair Value of Financial Instruments (Pension Plan Assets Measured At Fair Value On Recurring Basis) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments as fair value	$ 2,692	$ 2,514
Receivable for plan assets of the CTF Operations		258
Interest and Dividends Receivable	6	6
Due from Broker for Securities Sold	40	27
Receivable Associated with Insurance Contract	7	7
Due to Broker for Securities Purchased	(71)	(46)
Total Plan Assets, at Fair Value	2,674	2,766
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments as fair value	884	863
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments as fair value	1,693	1,533
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments as fair value	115	118
Cash and Cash Equivalents [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments as fair value	37	42
Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments as fair value	37	42
U.S. Government Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments as fair value	30	29
U.S. Government Obligations [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments as fair value	30	29
Corporate and Other Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments as fair value	448	400
Corporate and Other Obligations [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments as fair value	448	400
Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments as fair value	523	487
Equity Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments as fair value	523	487
Commingled Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments as fair value	1,215	1,104
Commingled Funds [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments as fair value	1,215	1,104
Interest in Registered Investment Companies [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments as fair value	324	334
Interest in Registered Investment Companies [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments as fair value	324	334
Interest in Limited Partnerships and Limited Liability Companies [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments as fair value	115	118
Interest in Limited Partnerships and Limited Liability Companies [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments as fair value	$ 115	$ 118

Fair Value of Financial Instr96

Fair Value of Financial Instruments (Changes In Fair Value Of Plan's Level 3 Assets) (Details) - Interest in Limited Partnerships and Limited Liability Companies [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Balance, beginning of year	$ 118	$ 92
Realized gains	12	7
Unrealized (losses)	(2)	13
Purchases		15
Sales and distributions	(13)	(9)
Balance, end of year	$ 115	$ 118

Fair Value of Financial Instr97

Fair Value of Financial Instruments (Redemption Of The Plan's Level 3 Investments) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
MS IFHF SVP LP Cayman [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liquidation Period (in years)	5 years
MS IFHF SVP LP Alpha [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liquidation Period (in years)	5 years
RII World Timberfund, LLC [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liquidation Period (in years)	10 years
Interest in Limited Partnerships and Limited Liability Companies [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 115	$ 118	$ 92
Interest in Limited Partnerships and Limited Liability Companies [Member] | MS IFHF SVP LP Cayman [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	1
Interest in Limited Partnerships and Limited Liability Companies [Member] | MS IFHF SVP LP Alpha [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	1
Interest in Limited Partnerships and Limited Liability Companies [Member] | RII World Timberfund, LLC [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	5
Interest in Limited Partnerships and Limited Liability Companies [Member] | E Casino Road, LLC (member)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 15
Capitalization Rate	7.00%
Interest in Limited Partnerships and Limited Liability Companies [Member] | Comm Drive, LLC [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 9
Capitalization Rate	8.00%
Interest in Limited Partnerships and Limited Liability Companies [Member] | CTE Drive, LLC [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 10
Capitalization Rate	9.50%
Interest in Limited Partnerships and Limited Liability Companies [Member] | Oakbrook Parkway LLC [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 26
Capitalization Rate	7.75%
Interest in Limited Partnerships and Limited Liability Companies [Member] | West Jefferson, LLC [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 26
Capitalization Rate	8.75%
Interest in Limited Partnerships and Limited Liability Companies [Member] | MacCorkle Ave SE, LLC [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 14
Capitalization Rate	8.50%
Interest in Limited Partnerships and Limited Liability Companies [Member] | S Pike Road West, LLC [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 1
Capitalization Rate	8.50%
Interest in Limited Partnerships and Limited Liability Companies [Member] | N US 131, LLC [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 1
Capitalization Rate	9.50%
Interest in Limited Partnerships and Limited Liability Companies [Member] | E Stockton Blvd, LLC [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 6
Capitalization Rate	7.50%

Fair Value Of Financial Instr98

Fair Value Of Financial Instruments (Long Term Debt) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Carrying Amount [Member]
Long-term debt [Abstract]
Long-term debt	$ 16,970	$ 17,560
Fair Value [Member]
Long-term debt [Abstract]
Long-term debt	$ 13,994	$ 17,539

Commitments And Contingencies99

Commitments And Contingencies (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017USD ($)stateproperty	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Regulatory Commitments [Abstract]
Number of states of operation | state	29
Operating Leases [Abstract]
Term Of Lease Arrangements Lower Range	1 year
Term Of Lease Arrangements Upper Range	99 years
Rental expense	$ 106	$ 137	$ 119
CAF Phase II [Member]
Regulatory Commitments [Abstract]
Annual support offered by the Federal Communications Commission	$ 332
Number of households to be serviced under regulatory funded programs | property	774,000
CTF Transaction [Member] | CAF Phase II [Member]
Regulatory Commitments [Abstract]
Annual support offered by the Federal Communications Commission	$ 49

Commitments and Contingencie100

Commitments and Contingencies (Future Minimum Rental Commitments For All Long-Term Noncancelable Operating Leases) (Details) $ in Millions	Dec. 31, 2017USD ($)
Commitments And Contingencies [Abstract]
2,018	$ 80
2,019	25
2,020	29
2,021	26
2,022	23
Thereafter	388
Total minimum lease payments	$ 571

Commitments and Contingencie101

Commitments and Contingencies (Future Payments For Obligations Under Noncancelable Long Distance Contracts And Service Agreements) (Details) $ in Millions	Dec. 31, 2017USD ($)
Commitments And Contingencies [Abstract]
2,018	$ 37
2,019	40
2,020	31
2,021	7
2,022	2
Thereafter	9
Total	$ 126

Commitments and Contingencie102

Commitments and Contingencies (Outstanding Performance Letters Of Credit) (Details) - Letter of Credit [Member] $ in Millions	Dec. 31, 2017USD ($)
Line of Credit Facility [Line Items]
Line of credit, amount outstanding	$ 192
CNA [Member]
Line of Credit Facility [Line Items]
Line of credit, amount outstanding	49
AIG Insurance [Member]
Line of Credit Facility [Line Items]
Line of credit, amount outstanding	114
Zurich [Member]
Line of Credit Facility [Line Items]
Line of credit, amount outstanding	28
Other Letters of Credit [Member]
Line of Credit Facility [Line Items]
Line of credit, amount outstanding	$ 1