Commitments, Contingencies and Other Items (Notes)	9 Months Ended
Sep. 30, 2016
Commitments and Contingencies Disclosure [Abstract]
Commitments, Contingencies and Other Items	Commitments, Contingencies and Other Items The Company is subject to various legal proceedings and other contingent liabilities that individually or in the aggregate could materially affect its financial condition, future results of operations or cash flows. Amounts accrued for such contingencies aggregate to $113 million and are included in “Other” current liabilities and “Other Liabilities” in the Company's Consolidated Balance Sheet at September 30, 2016. The establishment of an accrual does not mean that actual funds have been set aside to satisfy a given contingency. Thus, the resolution of a particular contingency for the amount accrued would have no effect on the Company's results of operations but could materially adversely affect its cash flows for the affected period. The Company reviews its accruals at least quarterly and adjusts them to reflect the impact of negotiations, settlements, rulings, advice of legal counsel and other information and events pertaining to a particular matter. Below is a description of material legal proceedings and other contingencies pending at September 30, 2016. Although the Company believes it has accrued for these matters in accordance with the accounting guidance for contingencies, contingencies are inherently unpredictable and it is possible that results of operations or cash flows could be materially and adversely affected in any particular period by unfavorable developments in, or resolution or disposition of, one or more of these matters. For those contingencies in respect of which the Company believes that it is reasonably possible that a loss may result that is materially in excess of the accrual (if any) established for the matter, the Company has either provided an estimate of such possible loss or range of loss or included a statement that such an estimate cannot be made. In addition to the contingencies described below, the Company is party to many other legal proceedings and contingencies, the resolution of which is not expected to materially affect its financial condition or future results of operations beyond the amounts accrued. Rights-of-Way Litigation The Company is party to a number of purported class action lawsuits involving its right to install fiber optic cable network in railroad right-of-ways adjacent to plaintiffs' land. In general, the Company obtained the rights to construct its networks from railroads, utilities, and others, and has installed its networks along the rights-of-way so granted. Plaintiffs in the purported class actions assert that they are the owners of lands over which the fiber optic cable networks pass, and that the railroads, utilities and others who granted the Company the right to construct and maintain its network did not have the legal authority to do so. The complaints seek damages on theories of trespass, unjust enrichment and slander of title and property, as well as punitive damages. The Company has also received, and may in the future receive, claims and demands related to rights-of-way issues similar to the issues in these cases that may be based on similar or different legal theories. The Company has defeated motions for class certification in a number of these actions but expects that, absent settlement of these actions, plaintiffs in the pending lawsuits will continue to seek certification of statewide or multi-state classes. The only lawsuit in which a class was certified against the Company, absent an agreed upon settlement, occurred in Koyle, et. al. v. Level 3 Communications, Inc., et. al., a purported two state class action filed in the United States District Court for the District of Idaho. The Koyle lawsuit has been dismissed pursuant to a settlement reached in November 2010 as described further below. The Company negotiated a series of class settlements affecting all persons who own or owned land next to or near railroad rights of way in which it has installed its fiber optic cable networks. The United States District Court for the District of Massachusetts in Kingsborough v. Sprint Communications Co. L.P. granted preliminary approval of the proposed settlement; however, on September 10, 2009, the court denied a motion for final approval of the settlement on the basis that the court lacked subject matter jurisdiction and dismissed the case. In November 2010, the Company negotiated revised settlement terms for a series of state class settlements affecting all persons who own or owned land next to or near railroad rights of way in which the Company has installed its fiber optic cable networks. The Company is currently pursuing presentment of the settlement in applicable jurisdictions. The settlements, affecting current and former landowners, have received final federal court approval in all but one of the applicable states and the parties are actively engaged in, or have completed, the claims process for the vast majority of the applicable states, including payment of claims. The Company continues to seek approval in the remaining two states. Management believes that the Company has substantial defenses to the claims asserted in all of these actions and intends to defend them vigorously if a satisfactory settlement is not ultimately approved for all affected landowners. Peruvian Tax Litigation Beginning in 2005, one of the Company's Peruvian subsidiaries received a number of assessments for tax, penalties and interest for calendar years 2001 and 2002. Peruvian tax authorities ("SUNAT") took the position that the Peruvian subsidiary incorrectly documented its importations resulting in additional income tax withholding and value-added taxes ("VAT"). The total amount of the asserted claims, including potential interest and penalties, was $26 million, consisting of $3 million for income tax withholding in connection with the import of services for calendar years 2001 and 2002, $7 million for VAT in connection with the import of services for calendar years 2001 and 2002, and $16 million in connection with the disallowance of VAT credits for periods beginning in 2005. After taking into account the developments described below, as well as the accrued interest and foreign exchange effects, the total amount of exposure is $29 million at September 30, 2016. The Company challenged the tax assessments during 2005 by filing administrative claims before SUNAT. During August 2006 and June 2007, SUNAT rejected the Company's administrative claims, thereby confirming the assessments. Appeals were filed in September 2006 and July 2007 with the Tribunal Fiscal, the highest level of administrative review, which is not part of the Peru judiciary (the "Tribunal"). The 2001 and 2002 assessed withholding tax assessments were resolved in favor of the Company in separate administrative resolutions; however, the penalties with respect to withholding tax remain at issue in the administrative appeals. In October 2011, the Tribunal issued its administrative resolution with respect to the calendar year 2002 tax period regarding VAT, associated penalties and penalties associated with withholding taxes, deciding the central issue underlying the assessments in the government's favor, while confirming the assessment in part and denying a portion of the assessment on procedural grounds. The Company appealed the Tribunal's October 2011 administrative resolutions to the judicial court in Peru. In September 2014, the first judicial court rendered a decision largely in the Company’s favor on the central issue underlying the assessments. SUNAT appealed the court’s decision to the next judicial level. The court of appeal remanded the case to the first judicial court for further development of the facts and legal analysis supporting its decision. In April 2016, the first judicial level rendered a decision in the Company’s favor on the central issue underlying the assessments. SUNAT has appealed the substantive issue to the next judicial level. The Company also appealed certain procedural points. In October 2013, the Tribunal notified the Company of its July 2013 administrative resolution with respect to the calendar year 2001 tax period regarding VAT, associated penalties and penalties associated with withholding taxes, determining the central issue underlying the assessments in the government's favor, while confirming the assessment in part and denying a portion of the assessment on procedural grounds. The Company appealed the Tribunal's July 2013 administrative resolutions to the judicial court in Peru. In April 2015, the first judicial court rendered a decision largely in SUNAT’s favor on the central issue underlying the assessments. The Company appealed the court’s decision to the next judicial level. In April 2016, the court of appeal rendered a decision that declared null the April 2015 decision and remanded the case to the first judicial court for further development of the facts and legal analysis supporting its decision. In December 2013, SUNAT initiated an audit of calendar year 2001. In June 2014, the Company was served with SUNAT’s assessments of the 2001 VAT credits declared null by the Tribunal and the corresponding fine. In July 2014, the Company challenged these assessments by filing administrative claims before SUNAT. In January 2015, SUNAT rejected the administrative claims, thereby confirming the assessments. The Company filed an appeal with the Tribunal in February 2015. In May 2015, the Tribunal notified the Company of its administrative resolution declaring the assessments and corresponding fines null. The time for SUNAT to appeal this resolution has closed. Under local practice, notification of an appeal can take several months. Counsel confirmed in the first quarter of 2016 that SUNAT has not filed an appeal to the resolution. Nevertheless, SUNAT retains the right to reissue the assessments declared null or start a new audit. However, the Company is under no obligation to provide additional information and any fine issued by SUNAT based on the same information that it has already used in the past would be declared null. Accordingly, in March 2016, the Company released an accrual of approximately $15 million for an assessment and associated interest. Employee Severance and Contractor Termination Disputes A number of former employees and third-party contractors have asserted a variety of claims in litigation against certain Latin American subsidiaries of the Company for separation pay, severance, commissions, pension benefits, unpaid vacation pay, breach of employment contracts, unpaid performance bonuses, property damages, moral damages and related statutory penalties, fines, costs and expenses (including accrued interest, attorneys fees and statutorily mandated inflation adjustments) as a result of their separation from the Company or termination of service relationships. The Company is vigorously defending itself against the asserted claims, which aggregate to approximately $29 million at September 30, 2016. Brazilian Tax Claims In December 2004, March 2009, April 2009 and July 2014, the São Paulo state tax authorities issued tax assessments against one of the Company's Brazilian subsidiaries for the Tax on Distribution of Goods and Services (“ICMS”) with respect to revenue from leasing movable properties (in the case of the December 2004, March 2009 and July 2014 assessments) and revenue from the provision of Internet access services (in the case of the April 2009 and July 2014 assessments), by treating such activities as the provision of communications services, to which the ICMS tax applies. During the third quarter of 2014, the Company released an accrual of $6 million for tax, penalty and associated interest corresponding to the ICMS applicable on the provision of Internet access services due to the expiration of the statute of limitations for the January 2008 to June 2009 tax periods. In September 2002, July 2009 and May 2012, the Rio de Janeiro state tax authorities issued tax assessments to the same Brazilian subsidiary on similar issues. The Company has filed objections to these assessments, arguing that the lease of assets and the provision of Internet access are not communication services subject to ICMS. The objections to the September 2002, December 2004 and March 2009 assessments were rejected by the respective state administrative courts, and the Company has appealed those decisions to the judicial courts. In October 2012 and June 2014, the Company received favorable rulings from the lower court on the December 2004 and March 2009 assessments regarding equipment leasing, but those rulings are subject to appeal by the state. No ruling has been obtained with respect to the September 2002 assessment. The objections to the April and July 2009 and May 2012 assessments are still pending final administrative decisions. The July 2014 assessment was confirmed during the fourth quarter of 2014 at the first administrative level and the Company appealed this decision to the second administrative level. During the fourth quarter of 2014, the Company entered into an amnesty with the Rio de Janeiro state tax authorities with respect to potential ICMS liability for the 2008 tax period. As a result, the Company paid $5 million and released an accrual of $3 million of tax corresponding to the ICMS applicable on the provision of Internet access services in the fourth quarter of 2014. The Company is vigorously contesting all such assessments in both states, and in particular, views the assessment of ICMS on revenue from leasing movable properties to be without merit. Nevertheless, the Company believes that it is reasonably possible that these assessments could result in a loss of up to $48 million at September 30, 2016 in excess of the accruals established for these matters. Letters of Credit It is customary for Level 3 to use various financial instruments in the normal course of business. These instruments include letters of credit. Letters of credit are conditional commitments issued on behalf of Level 3 in accordance with specified terms and conditions. As of September 30, 2016 and December 31, 2015, Level 3 had outstanding letters of credit or other similar obligations of approximately $39 million and $46 million, respectively, of which $33 million and $43 million are collateralized by cash that is reflected on the Consolidated Balance Sheets as restricted cash and securities. The Company does not believe exposure to loss related to its letters of credit is material.

Commitments, Contingencies and Other Items

The Company is subject to various legal proceedings and other contingent liabilities that individually or in the aggregate could materially affect its financial condition, future results of operations or cash flows. Amounts accrued for such contingencies aggregate to $113 million and are included in “Other” current liabilities and “Other Liabilities” in the Company's Consolidated Balance Sheet at September 30, 2016. The establishment of an accrual does not mean that actual funds have been set aside to satisfy a given contingency. Thus, the resolution of a particular contingency for the amount accrued would have no effect on the Company's results of operations but could materially adversely affect its cash flows for the affected period.

The Company reviews its accruals at least quarterly and adjusts them to reflect the impact of negotiations, settlements, rulings, advice of legal counsel and other information and events pertaining to a particular matter. Below is a description of material legal proceedings and other contingencies pending at September 30, 2016. Although the Company believes it has accrued for these matters in accordance with the accounting guidance for contingencies, contingencies are inherently unpredictable and it is possible that results of operations or cash flows could be materially and adversely affected in any particular period by unfavorable developments in, or resolution or disposition of, one or more of these matters. For those contingencies in respect of which the Company believes that it is reasonably possible that a loss may result that is materially in excess of the accrual (if any) established for the matter, the Company has either provided an estimate of such possible loss or range of loss or included a statement that such an estimate cannot be made. In addition to the contingencies described below, the Company is party to many other legal proceedings and contingencies, the resolution of which is not expected to materially affect its financial condition or future results of operations beyond the amounts accrued.

Rights-of-Way Litigation

The Company is party to a number of purported class action lawsuits involving its right to install fiber optic cable network in railroad right-of-ways adjacent to plaintiffs' land. In general, the Company obtained the rights to construct its networks from railroads, utilities, and others, and has installed its networks along the rights-of-way so granted. Plaintiffs in the purported class actions assert that they are the owners of lands over which the fiber optic cable networks pass, and that the railroads, utilities and others who granted the Company the right to construct and maintain its network did not have the legal authority to do so. The complaints seek damages on theories of trespass, unjust enrichment and slander of title and property, as well as punitive damages. The Company has also received, and may in the future receive, claims and demands related to rights-of-way issues similar to the issues in these cases that may be based on similar or different legal theories. The Company has defeated motions for class certification in a number of these actions but expects that, absent settlement of these actions, plaintiffs in the pending lawsuits will continue to seek certification of statewide or multi-state classes. The only lawsuit in which a class was certified against the Company, absent an agreed upon settlement, occurred in Koyle, et. al. v. Level 3 Communications, Inc., et. al., a purported two state class action filed in the United States District Court for the District of Idaho. The Koyle lawsuit has been dismissed pursuant to a settlement reached in November 2010 as described further below.

The Company negotiated a series of class settlements affecting all persons who own or owned land next to or near railroad rights of way in which it has installed its fiber optic cable networks. The United States District Court for the District of Massachusetts in Kingsborough v. Sprint Communications Co. L.P. granted preliminary approval of the proposed settlement; however, on September 10, 2009, the court denied a motion for final approval of the settlement on the basis that the court lacked subject matter jurisdiction and dismissed the case.

In November 2010, the Company negotiated revised settlement terms for a series of state class settlements affecting all persons who own or owned land next to or near railroad rights of way in which the Company has installed its fiber optic cable networks. The Company is currently pursuing presentment of the settlement in applicable jurisdictions. The settlements, affecting current and former landowners, have received final federal court approval in all but one of the applicable states and the parties are actively engaged in, or have completed, the claims process for the vast majority of the applicable states, including payment of claims. The Company continues to seek approval in the remaining two states.

Management believes that the Company has substantial defenses to the claims asserted in all of these actions and intends to defend them vigorously if a satisfactory settlement is not ultimately approved for all affected landowners.

Peruvian Tax Litigation

Beginning in 2005, one of the Company's Peruvian subsidiaries received a number of assessments for tax, penalties and interest for calendar years 2001 and 2002. Peruvian tax authorities ("SUNAT") took the position that the Peruvian subsidiary incorrectly documented its importations resulting in additional income tax withholding and value-added taxes ("VAT"). The total amount of the asserted claims, including potential interest and penalties, was $26 million, consisting of $3 million for income tax withholding in connection with the import of services for calendar years 2001 and 2002, $7 million for VAT in connection with the import of services for calendar years 2001 and 2002, and $16 million in connection with the disallowance of VAT credits for periods beginning in 2005. After taking into account the developments described below, as well as the accrued interest and foreign exchange effects, the total amount of exposure is $29 million at September 30, 2016.

The Company challenged the tax assessments during 2005 by filing administrative claims before SUNAT. During August 2006 and June 2007, SUNAT rejected the Company's administrative claims, thereby confirming the assessments. Appeals were filed in September 2006 and July 2007 with the Tribunal Fiscal, the highest level of administrative review, which is not part of the Peru judiciary (the "Tribunal"). The 2001 and 2002 assessed withholding tax assessments were resolved in favor of the Company in separate administrative resolutions; however, the penalties with respect to withholding tax remain at issue in the administrative appeals.

In October 2011, the Tribunal issued its administrative resolution with respect to the calendar year 2002 tax period regarding VAT, associated penalties and penalties associated with withholding taxes, deciding the central issue underlying the assessments in the government's favor, while confirming the assessment in part and denying a portion of the assessment on procedural grounds. The Company appealed the Tribunal's October 2011 administrative resolutions to the judicial court in Peru. In September 2014, the first judicial court rendered a decision largely in the Company’s favor on the central issue underlying the assessments. SUNAT appealed the court’s decision to the next judicial level. The court of appeal remanded the case to the first judicial court for further development of the facts and legal analysis supporting its decision. In April 2016, the first judicial level rendered a decision in the Company’s favor on the central issue underlying the assessments. SUNAT has appealed the substantive issue to the next judicial level. The Company also appealed certain procedural points.

In October 2013, the Tribunal notified the Company of its July 2013 administrative resolution with respect to the calendar year 2001 tax period regarding VAT, associated penalties and penalties associated with withholding taxes, determining the central issue underlying the assessments in the government's favor, while confirming the assessment in part and denying a portion of the assessment on procedural grounds. The Company appealed the Tribunal's July 2013 administrative resolutions to the judicial court in Peru. In April 2015, the first judicial court rendered a decision largely in SUNAT’s favor on the central issue underlying the assessments. The Company appealed the court’s decision to the next judicial level. In April 2016, the court of appeal rendered a decision that declared null the April 2015 decision and remanded the case to the first judicial court for further development of the facts and legal analysis supporting its decision.

In December 2013, SUNAT initiated an audit of calendar year 2001. In June 2014, the Company was served with SUNAT’s assessments of the 2001 VAT credits declared null by the Tribunal and the corresponding fine. In July 2014, the Company challenged these assessments by filing administrative claims before SUNAT. In January 2015, SUNAT rejected the administrative claims, thereby confirming the assessments. The Company filed an appeal with the Tribunal in February 2015. In May 2015, the Tribunal notified the Company of its administrative resolution declaring the assessments and corresponding fines null. The time for SUNAT to appeal this resolution has closed. Under local practice, notification of an appeal can take several months. Counsel confirmed in the first quarter of 2016 that SUNAT has not filed an appeal to the resolution. Nevertheless, SUNAT retains the right to reissue the assessments declared null or start a new audit. However, the Company is under no obligation to provide additional information and any fine issued by SUNAT based on the same information that it has already used in the past would be declared null. Accordingly, in March 2016, the Company released an accrual of approximately $15 million for an assessment and associated interest.

Employee Severance and Contractor Termination Disputes

A number of former employees and third-party contractors have asserted a variety of claims in litigation against certain Latin American subsidiaries of the Company for separation pay, severance, commissions, pension benefits, unpaid vacation pay, breach of employment contracts, unpaid performance bonuses, property damages, moral damages and related statutory penalties, fines, costs and expenses (including accrued interest, attorneys fees and statutorily mandated inflation adjustments) as a result of their separation from the Company or termination of service relationships. The Company is vigorously defending itself against the asserted claims, which aggregate to approximately $29 million at September 30, 2016.

Brazilian Tax Claims

In December 2004, March 2009, April 2009 and July 2014, the São Paulo state tax authorities issued tax assessments against one of the Company's Brazilian subsidiaries for the Tax on Distribution of Goods and Services (“ICMS”) with respect to revenue from leasing movable properties (in the case of the December 2004, March 2009 and July 2014 assessments) and revenue from the provision of Internet access services (in the case of the April 2009 and July 2014 assessments), by treating such activities as the provision of communications services, to which the ICMS tax applies. During the third quarter of 2014, the Company released an accrual of $6 million for tax, penalty and associated interest corresponding to the ICMS applicable on the provision of Internet access services due to the expiration of the statute of limitations for the January 2008 to June 2009 tax periods. In September 2002, July 2009 and May 2012, the Rio de Janeiro state tax authorities issued tax assessments to the same Brazilian subsidiary on similar issues. The Company has filed objections to these assessments, arguing that the lease of assets and the provision of Internet access are not communication services subject to ICMS. The objections to the September 2002, December 2004 and March 2009 assessments were rejected by the respective state administrative courts, and the Company has appealed those decisions to the judicial courts. In October 2012 and June 2014, the Company received favorable rulings from the lower court on the December 2004 and March 2009 assessments regarding equipment leasing, but those rulings are subject to appeal by the state. No ruling has been obtained with respect to the September 2002 assessment. The objections to the April and July 2009 and May 2012 assessments are still pending final administrative decisions. The July 2014 assessment was confirmed during the fourth quarter of 2014 at the first administrative level and the Company appealed this decision to the second administrative level. During the fourth quarter of 2014, the Company entered into an amnesty with the Rio de Janeiro state tax authorities with respect to potential ICMS liability for the 2008 tax period. As a result, the Company paid $5 million and released an accrual of $3 million of tax corresponding to the ICMS applicable on the provision of Internet access services in the fourth quarter of 2014.

The Company is vigorously contesting all such assessments in both states, and in particular, views the assessment of ICMS on revenue from leasing movable properties to be without merit. Nevertheless, the Company believes that it is reasonably possible that these assessments could result in a loss of up to $48 million at September 30, 2016 in excess of the accruals established for these matters.

Letters of Credit

It is customary for Level 3 to use various financial instruments in the normal course of business. These instruments include letters of credit. Letters of credit are conditional commitments issued on behalf of Level 3 in accordance with specified terms and conditions. As of September 30, 2016 and December 31, 2015, Level 3 had outstanding letters of credit or other similar obligations of approximately $39 million and $46 million, respectively, of which $33 million and $43 million are collateralized by cash that is reflected on the Consolidated Balance Sheets as restricted cash and securities. The Company does not believe exposure to loss related to its letters of credit is material.