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Long-Term Debt - Textuals (Details) (USD $)
 3 Months Ended 12 Months Ended 0 Months Ended 1 Months Ended 3 Months Ended 65 Months Ended 3 Months Ended 28 Months Ended 24 Months Ended 11 Months Ended 0 Months Ended 12 Months Ended 0 Months Ended 12 Months Ended 0 Months Ended 3 Months Ended 1 Months Ended 3 Months Ended 0 Months Ended 3 Months Ended
Dec. 31, 2014
Sep. 30, 2014
Jun. 30, 2014
Mar. 31, 2014
Dec. 31, 2013
Sep. 30, 2013
Jun. 30, 2013
Mar. 31, 2013
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Jun. 26, 2009
Nov. 01, 2014
Nov. 14, 2013
Aug. 31, 2012
Jun. 30, 2009
Jul. 31, 2012
Dec. 31, 2011
Oct. 31, 2011
Oct. 04, 2013
Sep. 30, 2012
Aug. 16, 2013
Aug. 01, 2013
Aug. 12, 2013
Oct. 04, 2013
Oct. 04, 2013
Nov. 26, 2013
Mar. 31, 2012
Feb. 28, 2012
Jan. 31, 2011
Jul. 31, 2011
Jun. 30, 2011
Oct. 15, 2009
Jun. 30, 2015
Mar. 31, 2007
Oct. 31, 2014
Aug. 06, 2012
Nov. 10, 2011
Mar. 13, 2007
Oct. 04, 2011
Oct. 04, 2012
Dec. 01, 2014
Mar. 04, 2011
Apr. 10, 2012
Jun. 09, 2011
Jan. 13, 2012
Aug. 12, 2014
Mar. 31, 2011
Jan. 29, 2015
Long-term debt                                                                                                  
Debt Conversion, Converted Instrument, Amount                 $ 142,000,000us-gaap_DebtConversionConvertedInstrumentAmount1 $ 200,000,000us-gaap_DebtConversionConvertedInstrumentAmount1 $ 100,000,000us-gaap_DebtConversionConvertedInstrumentAmount1                                                                            
Debt Instrument, Net Proceeds                 589,000,000us-gaap_ProceedsFromIssuanceOfLongTermDebtAndCapitalSecuritiesNet 1,502,000,000us-gaap_ProceedsFromIssuanceOfLongTermDebtAndCapitalSecuritiesNet 4,504,000,000us-gaap_ProceedsFromIssuanceOfLongTermDebtAndCapitalSecuritiesNet                                                                            
Accrued interest conversion into equity                 2,000,000lvlt_NonCashAccruedInterestPayment 3,000,000lvlt_NonCashAccruedInterestPayment 2,000,000lvlt_NonCashAccruedInterestPayment                                                                            
Loss on extinguishment of debt (53,000,000)us-gaap_GainsLossesOnExtinguishmentOfDebt 0us-gaap_GainsLossesOnExtinguishmentOfDebt 0us-gaap_GainsLossesOnExtinguishmentOfDebt 0us-gaap_GainsLossesOnExtinguishmentOfDebt (67,000,000)us-gaap_GainsLossesOnExtinguishmentOfDebt (17,000,000)us-gaap_GainsLossesOnExtinguishmentOfDebt 0us-gaap_GainsLossesOnExtinguishmentOfDebt 0us-gaap_GainsLossesOnExtinguishmentOfDebt (53,000,000)us-gaap_GainsLossesOnExtinguishmentOfDebt (84,000,000)us-gaap_GainsLossesOnExtinguishmentOfDebt (160,000,000)us-gaap_GainsLossesOnExtinguishmentOfDebt                                                                            
Future contractual maturities of long-term debt and capital leases (excluding issue discounts, premiums and fair value adjustments)                                                                                                  
2013 349,000,000lvlt_DebtAndCapitalLeaseObligationsMaturitiesRepaymentsOfPrincipalFirstFullFiscalYear               349,000,000lvlt_DebtAndCapitalLeaseObligationsMaturitiesRepaymentsOfPrincipalFirstFullFiscalYear                                                                                
2014 9,000,000lvlt_DebtAndCapitalLeaseObligationsMaturitiesRepaymentsOfPrincipalSecondFullFiscalYear               9,000,000lvlt_DebtAndCapitalLeaseObligationsMaturitiesRepaymentsOfPrincipalSecondFullFiscalYear                                                                                
2015 8,000,000lvlt_DebtAndCapitalLeaseObligationsMaturitiesRepaymentsOfPrincipalThirdFullFiscalYear               8,000,000lvlt_DebtAndCapitalLeaseObligationsMaturitiesRepaymentsOfPrincipalThirdFullFiscalYear                                                                                
2016 308,000,000lvlt_DebtAndCapitalLeaseObligationsMaturitiesRepaymentsOfPrincipalFourthFullFiscalYear               308,000,000lvlt_DebtAndCapitalLeaseObligationsMaturitiesRepaymentsOfPrincipalFourthFullFiscalYear                                                                                
2017 2,823,000,000lvlt_DebtAndCapitalLeaseObligationsMaturitiesRepaymentsOfPrincipalFifthFullFiscalYear               2,823,000,000lvlt_DebtAndCapitalLeaseObligationsMaturitiesRepaymentsOfPrincipalFifthFullFiscalYear                                                                                
Thereafter 7,869,000,000lvlt_DebtAndCapitalLeaseObligationsMaturitiesRepaymentsOfPrincipalAfterFifthFullFiscalYear               7,869,000,000lvlt_DebtAndCapitalLeaseObligationsMaturitiesRepaymentsOfPrincipalAfterFifthFullFiscalYear                                                                                
Total Debt Obligations 11,366,000,000lvlt_DebtInstrumentAndCapitalLeaseObligationsCarryingAmount               11,366,000,000lvlt_DebtInstrumentAndCapitalLeaseObligationsCarryingAmount                                                                                
Long-term Debt, Gross 11,366,000,000us-gaap_DebtInstrumentCarryingAmount       8,392,000,000us-gaap_DebtInstrumentCarryingAmount       11,366,000,000us-gaap_DebtInstrumentCarryingAmount 8,392,000,000us-gaap_DebtInstrumentCarryingAmount                                                                              
Level 3 Communications, Inc.                                                                                                  
Long-term debt                                                                                                  
Debt Instrument, Net Proceeds                 590,000,000us-gaap_ProceedsFromIssuanceOfLongTermDebtAndCapitalSecuritiesNet
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember		 0us-gaap_ProceedsFromIssuanceOfLongTermDebtAndCapitalSecuritiesNet
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember		 293,000,000us-gaap_ProceedsFromIssuanceOfLongTermDebtAndCapitalSecuritiesNet
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember		                                                                            
Repayments of Long-term Debt                       78,000,000us-gaap_RepaymentsOfLongTermDebt
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember		                                                                          
Level 3 Financing [Member]                                                                                                  
Long-term debt                                                                                                  
Loss on Cash Flow Hedge Ineffectiveness   60,000,000us-gaap_LossOnCashFlowHedgeIneffectiveness
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                                                                                              
Derivative, Notional Amount                                                                     1,000,000,000invest_DerivativeNotionalAmount
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                            
Guarantor Subsidiaries [Member]                                                                                                  
Long-term debt                                                                                                  
Debt Instrument, Net Proceeds                 0us-gaap_ProceedsFromIssuanceOfLongTermDebtAndCapitalSecuritiesNet
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember		 1,502,000,000us-gaap_ProceedsFromIssuanceOfLongTermDebtAndCapitalSecuritiesNet
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember		 4,211,000,000us-gaap_ProceedsFromIssuanceOfLongTermDebtAndCapitalSecuritiesNet
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember		                                                                            
TrancheB2022TermLoanTotal [Member]                                                                                                  
Future contractual maturities of long-term debt and capital leases (excluding issue discounts, premiums and fair value adjustments)                                                                                                  
Long-term Debt, Gross 2,000,000,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheB2022TermLoanTotalMember		               2,000,000,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheB2022TermLoanTotalMember		                                                                                
TrancheB2022TermLoanTotal [Member] | Guarantor Subsidiaries [Member]                                                                                                  
Future contractual maturities of long-term debt and capital leases (excluding issue discounts, premiums and fair value adjustments)                                                                                                  
Long-term Debt, Gross 2,000,000,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheB2022TermLoanTotalMember
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember		               2,000,000,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheB2022TermLoanTotalMember
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember		                                                                                
Tranche B 2022 Term Loans [Member]                                                                                                  
Long-term debt                                                                                                  
Debt instrument, stated interest rate (as a percent) 4.50%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheB2022TermLoansMember		               4.50%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheB2022TermLoansMember		                                                                                
Tranche B 2022 Term Loans [Member] | Guarantor Subsidiaries [Member]                                                                                                  
Long-term debt                                                                                                  
Debt Issuance Cost                         27,000,000us-gaap_DebtIssuanceCosts
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheB2022TermLoansMember
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember		                                                                        
Debt Instrument, Unamortized Discount 15,000,000us-gaap_DebtInstrumentUnamortizedDiscount
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheB2022TermLoansMember
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember		               15,000,000us-gaap_DebtInstrumentUnamortizedDiscount
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheB2022TermLoansMember
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember		                                                                                
Debt Instrument, Unamortized Debt Issuance Costs 26,000,000us-gaap_UnamortizedDebtIssuanceExpense
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheB2022TermLoansMember
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember		               26,000,000us-gaap_UnamortizedDebtIssuanceExpense
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheB2022TermLoansMember
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember		                                                                                
Future contractual maturities of long-term debt and capital leases (excluding issue discounts, premiums and fair value adjustments)                                                                                                  
Tranche B Term Loan 2022 upfront payment percentage                                                                       0.75%lvlt_TrancheBTermLoan2022upfrontpaymentpercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheB2022TermLoansMember
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember		                          
SeniorNotes6Point125PercentDue2021 [Member]                                                                                                  
Future contractual maturities of long-term debt and capital leases (excluding issue discounts, premiums and fair value adjustments)                                                                                                  
Long-term Debt, Gross 640,000,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes6Point125PercentDue2021Member		       640,000,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes6Point125PercentDue2021Member		       640,000,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes6Point125PercentDue2021Member		 640,000,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes6Point125PercentDue2021Member		                                                                              
SeniorNotes6Point125PercentDue2021 [Member] | Level 3 Financing [Member]                                                                                                  
Long-term debt                                                                                                  
Debt Instrument, Face Amount                           640,000,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes6Point125PercentDue2021Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                                                                      
Debt instrument, stated interest rate (as a percent) 6.125%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes6Point125PercentDue2021Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		               6.125%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes6Point125PercentDue2021Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                                                                                
Debt Instrument, Unamortized Debt Issuance Costs 11,000,000us-gaap_UnamortizedDebtIssuanceExpense
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes6Point125PercentDue2021Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		               11,000,000us-gaap_UnamortizedDebtIssuanceExpense
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes6Point125PercentDue2021Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		         12,000,000us-gaap_UnamortizedDebtIssuanceExpense
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes6Point125PercentDue2021Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                                                                      
Loss on extinguishment of debt                           56,000,000us-gaap_GainsLossesOnExtinguishmentOfDebt
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes6Point125PercentDue2021Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                                                                      
SeniorNotes6Point125PercentDue2021 [Member] | Level 3 Financing [Member] | Twelve Months Beginning November 15, 2016 [Member]                                                                                                  
Long-term debt                                                                                                  
Debt instrument, redemption price of principal amount (as percent)                 103.063%lvlt_DebtInstrumentRedemptionPriceAsPercentageOfPrincipalAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes6Point125PercentDue2021Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_TwelveMonthsBeginningNovember152016Member		                                                                                
SeniorNotes6Point125PercentDue2021 [Member] | Level 3 Financing [Member] | Twelve Months Beginning November 15, 2017 [Member]                                                                                                  
Long-term debt                                                                                                  
Debt instrument, redemption price of principal amount (as percent)                 101.531%lvlt_DebtInstrumentRedemptionPriceAsPercentageOfPrincipalAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes6Point125PercentDue2021Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_TwelveMonthsBeginningNovember152017Member		                                                                                
SeniorNotes6Point125PercentDue2021 [Member] | Level 3 Financing [Member] | Prior to June 2015                                                                                                  
Long-term debt                                                                                                  
Debt instrument, redemption with net proceeds from equity offerings of original principal (as percent)                 35.00%lvlt_DebtInstrumentRedemptionWithNetProceedsFromEquityOfferingsAsPercentageOfOriginalPrincipal
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes6Point125PercentDue2021Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriorToJune2015Member		                                                                                
Debt instrument, redemption price with net proceeds from equity offerings of original principal (as percent)                 106.125%lvlt_DebtInstrumentRedemptionPriceWithNetProceedsFromEquityOfferingsAsPercentageOfOriginalPrincipal
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes6Point125PercentDue2021Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriorToJune2015Member		                                                                                
Debt instrument, minimum percentage of original principal amount outstanding after redemption from equity offerings (as percent) 65.00%lvlt_DebtInstrumentMinimumPercentageOfOriginalPrincipalAmountOutstandingAfterRedemptionFromEquityOfferings
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes6Point125PercentDue2021Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriorToJune2015Member		               65.00%lvlt_DebtInstrumentMinimumPercentageOfOriginalPrincipalAmountOutstandingAfterRedemptionFromEquityOfferings
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes6Point125PercentDue2021Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriorToJune2015Member		                                                                                
SeniorNotes6Point125PercentDue2021 [Member] | Level 3 Financing [Member] | Prior to June 2016                                                                                                  
Long-term debt                                                                                                  
Debt instrument, redemption price of principal amount (as percent)                 100.00%lvlt_DebtInstrumentRedemptionPriceAsPercentageOfPrincipalAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes6Point125PercentDue2021Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriorToJune2016Member		                                                                                
SeniorNotes6Point125PercentDue2021 [Member] | Level 3 Financing [Member] | Prior to November 2015 [Member]                                                                                                  
Long-term debt                                                                                                  
Debt instrument, redemption period maximum following receipt of proceeds from equity offerings (number of days)                 90lvlt_DebtInstrumentRedemptionPeriodMaximumFollowingReceiptOfProceedsFromEquityOfferings
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes6Point125PercentDue2021Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriortoNovember2016Member		                                                                                
Debt instrument, redemption period notice minimum (number of days)                 30lvlt_DebtInstrumentRedemptionPeriodNoticeMinimumNumberOfDays
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes6Point125PercentDue2021Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriortoNovember2016Member		                                                                                
Debt instrument, redemption period notice maximum (number of days)                 60lvlt_DebtInstrumentRedemptionPeriodNoticeMaximumNumberOfDays
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes6Point125PercentDue2021Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriortoNovember2016Member		                                                                                
SeniorNotes6Point125PercentDue2021 [Member] | Level 3 Financing [Member] | Twelve Months Beginning November 15, 2018 [Member]                                                                                                  
Long-term debt                                                                                                  
Debt instrument, redemption price of principal amount (as percent)                 100.00%lvlt_DebtInstrumentRedemptionPriceAsPercentageOfPrincipalAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes6Point125PercentDue2021Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_TwelveMonthsBeginningNovember152018Member		                                                                                
Senior Notes 7 Percent Due 2020 [Member]                                                                                                  
Long-term debt                                                                                                  
Debt instrument, stated interest rate (as a percent) 7.00%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes7PercentDue2020Member		               7.00%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes7PercentDue2020Member		                                                                                
Future contractual maturities of long-term debt and capital leases (excluding issue discounts, premiums and fair value adjustments)                                                                                                  
Long-term Debt, Gross 775,000,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes7PercentDue2020Member		       775,000,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes7PercentDue2020Member		       775,000,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes7PercentDue2020Member		 775,000,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes7PercentDue2020Member		                                                                              
Senior Notes 7 Percent Due 2020 [Member] | Level 3 Financing [Member]                                                                                                  
Long-term debt                                                                                                  
Debt Instrument, Face Amount                                                                         775,000,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes7PercentDue2020Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                        
Debt instrument, stated interest rate (as a percent) 7.00%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes7PercentDue2020Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		               7.00%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes7PercentDue2020Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                                                                                
Debt Instrument, Unamortized Debt Issuance Costs 11,000,000us-gaap_UnamortizedDebtIssuanceExpense
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes7PercentDue2020Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		               11,000,000us-gaap_UnamortizedDebtIssuanceExpense
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes7PercentDue2020Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                                                       15,000,000us-gaap_UnamortizedDebtIssuanceExpense
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes7PercentDue2020Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                        
Debt instrument, redemption price of principal amount (as percent)                             100.00%lvlt_DebtInstrumentRedemptionPriceAsPercentageOfPrincipalAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes7PercentDue2020Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                                                                    
Senior Notes 7 Percent Due 2020 [Member] | Level 3 Financing [Member] | Twelve Months Beginning June 1, 2016 [Member]                                                                                                  
Long-term debt                                                                                                  
Debt instrument, redemption price of principal amount (as percent)                 103.50%lvlt_DebtInstrumentRedemptionPriceAsPercentageOfPrincipalAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes7PercentDue2020Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_TwelveMonthsBeginningJune12016Member		                                                                                
Senior Notes 7 Percent Due 2020 [Member] | Level 3 Financing [Member] | Twelve Months Beginning June 1, 2017                                                                                                  
Long-term debt                                                                                                  
Debt instrument, redemption price of principal amount (as percent)                 101.75%lvlt_DebtInstrumentRedemptionPriceAsPercentageOfPrincipalAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes7PercentDue2020Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_TwelveMonthsBeginningJune12017Member		                                                                                
Senior Notes 7 Percent Due 2020 [Member] | Level 3 Financing [Member] | Twelve Months Beginning June 1, 2018                                                                                                  
Long-term debt                                                                                                  
Debt instrument, redemption price of principal amount (as percent)                 100.00%lvlt_DebtInstrumentRedemptionPriceAsPercentageOfPrincipalAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes7PercentDue2020Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_TwelveMonthsBeginningJune12018Member		                                                                                
Senior Notes 7 Percent Due 2020 [Member] | Level 3 Financing [Member] | Prior to June 2015                                                                                                  
Long-term debt                                                                                                  
Debt instrument, redemption minimum gross proceeds from equity offering ($100 million)                 100,000,000lvlt_DebtInstrumentRedemptionMinimumGrossProceedsFromEquityOffering
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes7PercentDue2020Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriorToJune2015Member		                                                                                
Debt instrument, redemption with net proceeds from equity offerings of original principal (as percent)                 35.00%lvlt_DebtInstrumentRedemptionWithNetProceedsFromEquityOfferingsAsPercentageOfOriginalPrincipal
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes7PercentDue2020Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriorToJune2015Member		                                                                                
Debt instrument, redemption price with net proceeds from equity offerings of original principal (as percent)                 107.00%lvlt_DebtInstrumentRedemptionPriceWithNetProceedsFromEquityOfferingsAsPercentageOfOriginalPrincipal
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes7PercentDue2020Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriorToJune2015Member		                                                                                
Debt instrument, minimum percentage of original principal amount outstanding after redemption from equity offerings (as percent) 65.00%lvlt_DebtInstrumentMinimumPercentageOfOriginalPrincipalAmountOutstandingAfterRedemptionFromEquityOfferings
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes7PercentDue2020Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriorToJune2015Member		               65.00%lvlt_DebtInstrumentMinimumPercentageOfOriginalPrincipalAmountOutstandingAfterRedemptionFromEquityOfferings
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes7PercentDue2020Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriorToJune2015Member		                                                                                
Debt instrument, redemption period maximum following receipt of proceeds from equity offerings (number of days)                 90lvlt_DebtInstrumentRedemptionPeriodMaximumFollowingReceiptOfProceedsFromEquityOfferings
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes7PercentDue2020Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriorToJune2015Member		                                                                                
Debt instrument, redemption period notice minimum (number of days)                 30lvlt_DebtInstrumentRedemptionPeriodNoticeMinimumNumberOfDays
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes7PercentDue2020Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriorToJune2015Member		                                                                                
Debt instrument, redemption period notice maximum (number of days)                 60lvlt_DebtInstrumentRedemptionPeriodNoticeMaximumNumberOfDays
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes7PercentDue2020Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriorToJune2015Member		                                                                                
Senior Notes 7 Percent Due 2020 [Member] | Level 3 Financing [Member] | Prior to June 2016                                                                                                  
Long-term debt                                                                                                  
Debt instrument, redemption price of principal amount (as percent)                 100.00%lvlt_DebtInstrumentRedemptionPriceAsPercentageOfPrincipalAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes7PercentDue2020Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriorToJune2016Member		                                                                                
Debt instrument, redemption period notice minimum (number of days)                 30lvlt_DebtInstrumentRedemptionPeriodNoticeMinimumNumberOfDays
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes7PercentDue2020Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriorToJune2016Member		                                                                                
Debt instrument, redemption period notice maximum (number of days)                 60lvlt_DebtInstrumentRedemptionPeriodNoticeMaximumNumberOfDays
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes7PercentDue2020Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriorToJune2016Member		                                                                                
TrancheB2020TermLoanTotal [Member] | Guarantor Subsidiaries [Member]                                                                                                  
Future contractual maturities of long-term debt and capital leases (excluding issue discounts, premiums and fair value adjustments)                                                                                                  
Long-term Debt, Gross 1,796,000,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheB2020TermLoanTotalMember
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember		               1,796,000,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheB2020TermLoanTotalMember
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember		                                                                                
Term Loans                                                                                                  
Future contractual maturities of long-term debt and capital leases (excluding issue discounts, premiums and fair value adjustments)                                                                                                  
Long-term Debt, Gross 4,611,000,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_TermLoansMember		 [1]       2,611,000,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_TermLoansMember		 [1]       4,611,000,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_TermLoansMember		 [1] 2,611,000,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_TermLoansMember		 [1]                                                                              
Senior Secured Term Loan 2011 | Level 3 Financing [Member]                                                                                                  
Long-term debt                                                                                                  
Repayments of Long-term Debt                               730,000,000us-gaap_RepaymentsOfLongTermDebt
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorSecuredTermLoan2011Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                                                                  
Tranche A Term Loan                                                                                                  
Long-term debt                                                                                                  
Debt instrument, Interest spread on debt (as percent)                                 2.25%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheTermLoanMember		                                                                
Loss on extinguishment of debt   (9,000,000)us-gaap_GainsLossesOnExtinguishmentOfDebt
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheTermLoanMember		                                                                                              
Tranche A Term Loan | Level 3 Financing [Member]                                                                                                  
Long-term debt                                                                                                  
Debt Instrument, Face Amount                                                                           1,400,000,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheTermLoanMember
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		 1,400,000,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheTermLoanMember
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                    
Debt instrument, Interest spread on debt (as percent)                                 2.25%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheTermLoanMember
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                                                                
Debt instrument, effective interest rate at end of period (as a percent)                                   2.65%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheTermLoanMember
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                                                              
Tranche B Term Loan | Level 3 Financing [Member]                                                                                                  
Long-term debt                                                                                                  
Debt Instrument, Face Amount                               280,000,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheBTermLoanMember
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                                                                  
Debt instrument, basis floor (as percent)                               3.00%lvlt_DebtInstrumentBasisFloor
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheBTermLoanMember
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                                                                  
Debt instrument, Interest spread on debt (as percent)                                     8.50%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheBTermLoanMember
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                                                            
Repayments of Long-term Debt                                   280,000,000us-gaap_RepaymentsOfLongTermDebt
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheBTermLoanMember
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                                                              
Tranche B II Term Loan                                                                                                  
Long-term debt                                                                                                  
Debt instrument, basis floor (as percent)                                   1.50%lvlt_DebtInstrumentBasisFloor
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheBIiTermLoanSixHundredFiftyMillionDollarsMember		                                                              
Debt instrument, Interest spread on debt (as percent)                                       4.25%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheBIiTermLoanSixHundredFiftyMillionDollarsMember		                                                          
Tranche B II Term Loan | Level 3 Financing [Member]                                                                                                  
Long-term debt                                                                                                  
Debt Instrument, Face Amount 650,000,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheBIiTermLoanSixHundredFiftyMillionDollarsMember
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		               650,000,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheBIiTermLoanSixHundredFiftyMillionDollarsMember
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                                                                                
Debt Instrument, Additional Borrowings                                   650,000,000us-gaap_ProceedsFromIssuanceOfDebt
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheBIiTermLoanSixHundredFiftyMillionDollarsMember
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                                                              
Debt instrument, basis floor (as percent) 1.50%lvlt_DebtInstrumentBasisFloor
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheBIiTermLoanSixHundredFiftyMillionDollarsMember
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		               1.50%lvlt_DebtInstrumentBasisFloor
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheBIiTermLoanSixHundredFiftyMillionDollarsMember
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                                                                                
Debt instrument, Interest spread on debt (as percent)                                       4.25%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheBIiTermLoanSixHundredFiftyMillionDollarsMember
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                                                          
Debt Instrument, Unamortized Discount                                                                               7,000,000us-gaap_DebtInstrumentUnamortizedDiscount
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheBIiTermLoanSixHundredFiftyMillionDollarsMember
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                  
Debt instrument, redemption price of principal amount (as percent)                                   99.00%lvlt_DebtInstrumentRedemptionPriceAsPercentageOfPrincipalAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheBIiTermLoanSixHundredFiftyMillionDollarsMember
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                                                              
Tranche B III Term Loan                                                                                                  
Long-term debt                                                                                                  
Debt instrument, basis floor (as percent)                                   1.50%lvlt_DebtInstrumentBasisFloor
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheBIiiTermLoanFiveHundredFiftyMillionDollarsMember		                                                              
Debt instrument, Interest spread on debt (as percent)                                         4.25%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheBIiiTermLoanFiveHundredFiftyMillionDollarsMember		                                                        
Tranche B III Term Loan | Level 3 Financing [Member]                                                                                                  
Long-term debt                                                                                                  
Debt Instrument, Face Amount 550,000,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheBIiiTermLoanFiveHundredFiftyMillionDollarsMember
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		               550,000,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheBIiiTermLoanFiveHundredFiftyMillionDollarsMember
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                                                                                
Debt Instrument, Additional Borrowings                                   550,000,000us-gaap_ProceedsFromIssuanceOfDebt
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheBIiiTermLoanFiveHundredFiftyMillionDollarsMember
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                                                              
Debt instrument, basis floor (as percent) 1.50%lvlt_DebtInstrumentBasisFloor
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheBIiiTermLoanFiveHundredFiftyMillionDollarsMember
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		               1.50%lvlt_DebtInstrumentBasisFloor
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheBIiiTermLoanFiveHundredFiftyMillionDollarsMember
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                                                                                
Debt instrument, Interest spread on debt (as percent)                                         4.25%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheBIiiTermLoanFiveHundredFiftyMillionDollarsMember
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                                                        
Debt Instrument, Unamortized Discount                                                                           28,000,000us-gaap_DebtInstrumentUnamortizedDiscount
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheBIiiTermLoanFiveHundredFiftyMillionDollarsMember
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                      
Debt instrument, redemption price of principal amount (as percent)                                   95.00%lvlt_DebtInstrumentRedemptionPriceAsPercentageOfPrincipalAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheBIiiTermLoanFiveHundredFiftyMillionDollarsMember
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                                                              
Tranche B II and Tranche B III Term Loans                                                                                                  
Long-term debt                                                                                                  
Loss on extinguishment of debt (50,000,000)us-gaap_GainsLossesOnExtinguishmentOfDebt
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheBIiAndTrancheBIiiTermLoansMember		       (67,000,000)us-gaap_GainsLossesOnExtinguishmentOfDebt
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheBIiAndTrancheBIiiTermLoansMember		                                                                                        
Tranche B 2016 Term Loan                                                                                                  
Long-term debt                                                                                                  
Debt instrument, basis floor (as percent) 1.50%lvlt_DebtInstrumentBasisFloor
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheB2016TermLoanMember		               1.50%lvlt_DebtInstrumentBasisFloor
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheB2016TermLoanMember		                                                                                
Debt instrument, Interest spread on debt (as percent)                                             3.25%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheB2016TermLoanMember		                                                    
Repayments of Debt                                           595,500,000us-gaap_RepaymentsOfDebt
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheB2016TermLoanMember		                                                      
Tranche B 2016 Term Loan | Level 3 Financing [Member]                                                                                                  
Long-term debt                                                                                                  
Debt Instrument, Face Amount                                                                         600,000,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheB2016TermLoanMember
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                        
Debt instrument, Interest spread on debt (as percent)                                             3.25%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheB2016TermLoanMember
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                                                    
Debt Instrument, Unamortized Discount                                                                         3,000,000us-gaap_DebtInstrumentUnamortizedDiscount
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheB2016TermLoanMember
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                        
Debt Instrument, Unamortized Debt Issuance Costs                                                                         9,000,000us-gaap_UnamortizedDebtIssuanceExpense
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheB2016TermLoanMember
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                        
Debt instrument, redemption price of principal amount (as percent)                             99.50%lvlt_DebtInstrumentRedemptionPriceAsPercentageOfPrincipalAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheB2016TermLoanMember
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                                                                    
Debt instrument, Trance B 2016 Term Loan annual repayment (as percent)                                                                         0.25%lvlt_RepaymentPercentOfOriginalAggregatePrincipalAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheB2016TermLoanMember
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                        
Tranche B 2016 Term Loan | Guarantor Subsidiaries [Member]                                                                                                  
Long-term debt                                                                                                  
Loss on extinguishment of debt                                           8,000,000us-gaap_GainsLossesOnExtinguishmentOfDebt
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheB2016TermLoanMember
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember		                                                      
TrancheB2020TermLoan [Member] | Guarantor Subsidiaries [Member]                                                                                                  
Long-term debt                                                                                                  
Debt Instrument, Face Amount                                           595,500,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheB2020TermLoanMember
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember		                                                      
Debt Issuance Cost                                           7,000,000us-gaap_DebtIssuanceCosts
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheB2020TermLoanMember
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember		                                                      
Debt Instrument, Unamortized Debt Issuance Costs 17,000,000us-gaap_UnamortizedDebtIssuanceExpense
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheB2020TermLoanMember
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember		               17,000,000us-gaap_UnamortizedDebtIssuanceExpense
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheB2020TermLoanMember
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember		                                                                                
Tranche B 2019 Term Loan                                                                                                  
Long-term debt                                                                                                  
Debt instrument, basis floor (as percent) 1.50%lvlt_DebtInstrumentBasisFloor
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheB2019TermLoanMember		               1.50%lvlt_DebtInstrumentBasisFloor
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheB2019TermLoanMember		                                                                                
Debt instrument, Interest spread on debt (as percent)                                             3.75%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheB2019TermLoanMember		                                                    
Repayments of Debt                                               815,000,000us-gaap_RepaymentsOfDebt
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheB2019TermLoanMember		                                                  
Tranche B 2019 Term Loan | Level 3 Financing [Member]                                                                                                  
Long-term debt                                                                                                  
Debt Instrument, Face Amount                                                                         815,000,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheB2019TermLoanMember
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                        
Debt instrument, Interest spread on debt (as percent)                                             3.75%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheB2019TermLoanMember
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                                                    
Debt Instrument, Unamortized Discount                                                                         8,000,000us-gaap_DebtInstrumentUnamortizedDiscount
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheB2019TermLoanMember
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                        
Debt Instrument, Unamortized Debt Issuance Costs                                                                         12,000,000us-gaap_UnamortizedDebtIssuanceExpense
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheB2019TermLoanMember
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                        
Debt instrument, redemption price of principal amount (as percent)                             99.00%lvlt_DebtInstrumentRedemptionPriceAsPercentageOfPrincipalAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheB2019TermLoanMember
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                                                                    
Tranche B 2019 Term Loan | Guarantor Subsidiaries [Member]                                                                                                  
Long-term debt                                                                                                  
Debt Issuance Cost                                               10,000,000us-gaap_DebtIssuanceCosts
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheB2019TermLoanMember
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember		                                                  
Debt Instrument, Unamortized Debt Issuance Costs 9,000,000us-gaap_UnamortizedDebtIssuanceExpense
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheB2019TermLoanMember
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember		               9,000,000us-gaap_UnamortizedDebtIssuanceExpense
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheB2019TermLoanMember
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember		                                                                                
TrancheBIII2019TermLoan [Member] | Guarantor Subsidiaries [Member]                                                                                                  
Long-term debt                                                                                                  
Debt Instrument, Face Amount                                               815,000,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheBIII2019TermLoanMember
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember		                                                  
Debt Instrument, Unamortized Debt Issuance Costs 8,000,000us-gaap_UnamortizedDebtIssuanceExpense
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheBIII2019TermLoanMember
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember		               8,000,000us-gaap_UnamortizedDebtIssuanceExpense
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheBIII2019TermLoanMember
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember		                                                                                
Tranche B 2016 Term Loan and Tranche B 2019 Term Loan | Level 3 Financing [Member]                                                                                                  
Long-term debt                                                                                                  
Debt Instrument, Face Amount                                                                         1,415,000,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_NewSeniorSecuredTermLoanMember
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                        
Debt instrument, basis floor (as percent) 1.50%lvlt_DebtInstrumentBasisFloor
/ us-gaap_DebtInstrumentAxis
= lvlt_NewSeniorSecuredTermLoanMember
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		               1.50%lvlt_DebtInstrumentBasisFloor
/ us-gaap_DebtInstrumentAxis
= lvlt_NewSeniorSecuredTermLoanMember
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                                                                                
Tranche B-II 2019 Term Loan                                                                                                  
Long-term debt                                                                                                  
Debt instrument, basis floor (as percent) 1.50%lvlt_DebtInstrumentBasisFloor
/ us-gaap_DebtInstrumentAxis
= lvlt_Tranchebii2019TermloanMember		               1.50%lvlt_DebtInstrumentBasisFloor
/ us-gaap_DebtInstrumentAxis
= lvlt_Tranchebii2019TermloanMember		                                                                                
Debt instrument, Interest spread on debt (as percent)                                                 3.25%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
/ us-gaap_DebtInstrumentAxis
= lvlt_Tranchebii2019TermloanMember		                                                
Loss on extinguishment of debt         10,000,000us-gaap_GainsLossesOnExtinguishmentOfDebt
/ us-gaap_DebtInstrumentAxis
= lvlt_Tranchebii2019TermloanMember		                                                                                        
Tranche B-II 2019 Term Loan | Level 3 Financing [Member]                                                                                                  
Long-term debt                                                                                                  
Debt instrument, basis floor (as percent)                                                                                 1.50%lvlt_DebtInstrumentBasisFloor
/ us-gaap_DebtInstrumentAxis
= lvlt_Tranchebii2019TermloanMember
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                
Debt instrument, Interest spread on debt (as percent)                                                 3.25%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
/ us-gaap_DebtInstrumentAxis
= lvlt_Tranchebii2019TermloanMember
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                                                
Debt Instrument, Unamortized Debt Issuance Costs                                                                         13,000,000us-gaap_UnamortizedDebtIssuanceExpense
/ us-gaap_DebtInstrumentAxis
= lvlt_Tranchebii2019TermloanMember
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                        
Repayments of Debt                                                   1,200,000,000us-gaap_RepaymentsOfDebt
/ us-gaap_DebtInstrumentAxis
= lvlt_Tranchebii2019TermloanMember
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                                              
Tranche B-II 2019 Term Loan | Guarantor Subsidiaries [Member]                                                                                                  
Long-term debt                                                                                                  
Debt Issuance Cost                                                   11,000,000us-gaap_DebtIssuanceCosts
/ us-gaap_DebtInstrumentAxis
= lvlt_Tranchebii2019TermloanMember
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember		                                              
Loss on extinguishment of debt                                                   10,000,000us-gaap_GainsLossesOnExtinguishmentOfDebt
/ us-gaap_DebtInstrumentAxis
= lvlt_Tranchebii2019TermloanMember
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember		                                              
TrancheB2020TermLoanAdd-on [Member] | Guarantor Subsidiaries [Member]                                                                                                  
Long-term debt                                                                                                  
Debt Instrument, Face Amount                                       1,200,000,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheB2020TermLoanAddonMember
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember		         1,200,000,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheB2020TermLoanAddonMember
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember		 1,200,000,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheB2020TermLoanAddonMember
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember		                                              
Debt Issuance Cost                                                   3,000,000us-gaap_DebtIssuanceCosts
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheB2020TermLoanAddonMember
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember		                                              
Debt Instrument, Unamortized Discount                                       0.0025us-gaap_DebtInstrumentUnamortizedDiscount
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheB2020TermLoanAddonMember
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember		         0.0025us-gaap_DebtInstrumentUnamortizedDiscount
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheB2020TermLoanAddonMember
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember		 0.0025us-gaap_DebtInstrumentUnamortizedDiscount
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheB2020TermLoanAddonMember
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember		                                              
Floating Rate Senior Notes due 2018 [Member]                                                                                                  
Future contractual maturities of long-term debt and capital leases (excluding issue discounts, premiums and fair value adjustments)                                                                                                  
Long-term Debt, Gross 300,000,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_FloatingRateSeniorNotesdue2018Member		       300,000,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_FloatingRateSeniorNotesdue2018Member		       300,000,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_FloatingRateSeniorNotesdue2018Member		 300,000,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_FloatingRateSeniorNotesdue2018Member		                                                                              
Floating Rate Senior Notes due 2018 [Member] | Guarantor Subsidiaries [Member]                                                                                                  
Long-term debt                                                                                                  
Debt Instrument, Face Amount                                                     300,000,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_FloatingRateSeniorNotesdue2018Member
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember		                                            
Debt Issuance Cost                                                     5,000,000us-gaap_DebtIssuanceCosts
/ us-gaap_DebtInstrumentAxis
= lvlt_FloatingRateSeniorNotesdue2018Member
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember		                                            
Debt Instrument, Unamortized Debt Issuance Costs 3,000,000us-gaap_UnamortizedDebtIssuanceExpense
/ us-gaap_DebtInstrumentAxis
= lvlt_FloatingRateSeniorNotesdue2018Member
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember		               3,000,000us-gaap_UnamortizedDebtIssuanceExpense
/ us-gaap_DebtInstrumentAxis
= lvlt_FloatingRateSeniorNotesdue2018Member
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember		                                                                                
Loss on extinguishment of debt                                                     1,000,000us-gaap_GainsLossesOnExtinguishmentOfDebt
/ us-gaap_DebtInstrumentAxis
= lvlt_FloatingRateSeniorNotesdue2018Member
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember		                                            
Debt instrument, redemption minimum gross proceeds from equity offering ($100 million)                 100,000,000lvlt_DebtInstrumentRedemptionMinimumGrossProceedsFromEquityOffering
/ us-gaap_DebtInstrumentAxis
= lvlt_FloatingRateSeniorNotesdue2018Member
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember		                                                                                
Floating Rate Senior Notes due 2018 [Member] | Guarantor Subsidiaries [Member] | May 2016 through November 2016 [Member]                                                                                                  
Long-term debt                                                                                                  
Debt instrument, redemption price of principal amount (as percent)                 101.00%lvlt_DebtInstrumentRedemptionPriceAsPercentageOfPrincipalAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_FloatingRateSeniorNotesdue2018Member
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_May2016throughNovember2016Member		                                                                                
Floating Rate Senior Notes due 2018 [Member] | Guarantor Subsidiaries [Member] | May 2015 through May 2016 [Member]                                                                                                  
Long-term debt                                                                                                  
Debt instrument, redemption price of principal amount (as percent)                 102.00%lvlt_DebtInstrumentRedemptionPriceAsPercentageOfPrincipalAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_FloatingRateSeniorNotesdue2018Member
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_May2015throughMay2016Member		                                                                                
Floating Rate Senior Notes due 2018 [Member] | Guarantor Subsidiaries [Member] | Prior to May 2015 [Member] [Member]                                                                                                  
Long-term debt                                                                                                  
Debt instrument, redemption with net proceeds from equity offerings of original principal (as percent)                 35.00%lvlt_DebtInstrumentRedemptionWithNetProceedsFromEquityOfferingsAsPercentageOfOriginalPrincipal
/ us-gaap_DebtInstrumentAxis
= lvlt_FloatingRateSeniorNotesdue2018Member
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriortoMay2015MemberMember		                                                                                
Debt instrument, redemption price with net proceeds from equity offerings of original principal (as percent)                 100.00%lvlt_DebtInstrumentRedemptionPriceWithNetProceedsFromEquityOfferingsAsPercentageOfOriginalPrincipal
/ us-gaap_DebtInstrumentAxis
= lvlt_FloatingRateSeniorNotesdue2018Member
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriortoMay2015MemberMember		                                                                                
Debt instrument, minimum percentage of original principal amount outstanding after redemption from equity offerings (as percent) 65.00%lvlt_DebtInstrumentMinimumPercentageOfOriginalPrincipalAmountOutstandingAfterRedemptionFromEquityOfferings
/ us-gaap_DebtInstrumentAxis
= lvlt_FloatingRateSeniorNotesdue2018Member
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriortoMay2015MemberMember		               65.00%lvlt_DebtInstrumentMinimumPercentageOfOriginalPrincipalAmountOutstandingAfterRedemptionFromEquityOfferings
/ us-gaap_DebtInstrumentAxis
= lvlt_FloatingRateSeniorNotesdue2018Member
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriortoMay2015MemberMember		                                                                                
Debt instrument, redemption period maximum following receipt of proceeds from equity offerings (number of days)                 90lvlt_DebtInstrumentRedemptionPeriodMaximumFollowingReceiptOfProceedsFromEquityOfferings
/ us-gaap_DebtInstrumentAxis
= lvlt_FloatingRateSeniorNotesdue2018Member
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriortoMay2015MemberMember		                                                                                
Debt instrument, redemption period notice minimum (number of days)                 30lvlt_DebtInstrumentRedemptionPeriodNoticeMinimumNumberOfDays
/ us-gaap_DebtInstrumentAxis
= lvlt_FloatingRateSeniorNotesdue2018Member
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriortoMay2015MemberMember		                                                                                
Debt instrument, redemption period notice maximum (number of days)                 60lvlt_DebtInstrumentRedemptionPeriodNoticeMaximumNumberOfDays
/ us-gaap_DebtInstrumentAxis
= lvlt_FloatingRateSeniorNotesdue2018Member
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriortoMay2015MemberMember		                                                                                
Floating Rate Senior Notes due 2018 [Member] | Guarantor Subsidiaries [Member] | November 2016 and Thereafter [Member]                                                                                                  
Long-term debt                                                                                                  
Debt instrument, redemption price of principal amount (as percent)                 100.00%lvlt_DebtInstrumentRedemptionPriceAsPercentageOfPrincipalAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_FloatingRateSeniorNotesdue2018Member
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_November2016andThereafterMember		                                                                                
Senior Notes due 2014 (9.25%)                                                                                                  
Long-term debt                                                                                                  
Debt instrument, stated interest rate (as a percent)                                   9.25%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes9Point25PercentDue2014Member		                                                              
Loss on extinguishment of debt                                                       (22,000,000)us-gaap_GainsLossesOnExtinguishmentOfDebt
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes9Point25PercentDue2014Member		                                          
Senior Notes due 2014 (9.25%) | Level 3 Financing [Member]                                                                                                  
Long-term debt                                                                                                  
Debt instrument, stated interest rate (as a percent)                                   9.25%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes9Point25PercentDue2014Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                   9.25%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes9Point25PercentDue2014Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                                          
Repayments of Long-term Debt                                                         807,000,000us-gaap_RepaymentsOfLongTermDebt
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes9Point25PercentDue2014Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                                        
Debt instrument, redemption price of principal amount (as percent)                                                       102.313%lvlt_DebtInstrumentRedemptionPriceAsPercentageOfPrincipalAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes9Point25PercentDue2014Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                                          
Floating Rate Senior Notes due 2015                                                                                                  
Long-term debt                                                                                                  
Debt instrument, stated interest rate (as a percent) 3.846%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_FloatingRateSeniorNotesDue2015Member		               3.846%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_FloatingRateSeniorNotesDue2015Member		                 4.202%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_FloatingRateSeniorNotesDue2015Member		                                                              
Loss on extinguishment of debt         1,000,000us-gaap_GainsLossesOnExtinguishmentOfDebt
/ us-gaap_DebtInstrumentAxis
= lvlt_FloatingRateSeniorNotesDue2015Member		                                                                                        
Senior Notes due 2017 (8.75%)                                                                                                  
Long-term debt                                                                                                  
Debt instrument, stated interest rate (as a percent)                                   8.75%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point75PercentDue2017Member		                                                              
Loss on extinguishment of debt   (40,000,000)us-gaap_GainsLossesOnExtinguishmentOfDebt
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point75PercentDue2017Member		                                                                                              
Senior Notes due 2017 (8.75%) | Level 3 Financing [Member]                                                                                                  
Long-term debt                                                                                                  
Debt instrument, stated interest rate (as a percent)   8.75%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point75PercentDue2017Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                                                                                              
Debt instrument, redemption price of principal amount (as percent)   104.375%lvlt_DebtInstrumentRedemptionPriceAsPercentageOfPrincipalAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point75PercentDue2017Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                                                                                              
Senior Notes due 2018 (10.0%)                                                                                                  
Long-term debt                                                                                                  
Debt instrument, stated interest rate (as a percent) 10.00%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes10Point0PercentDue2018Member		       10.00%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes10Point0PercentDue2018Member		       10.00%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes10Point0PercentDue2018Member		 10.00%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes10Point0PercentDue2018Member		               10.00%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes10Point0PercentDue2018Member		                                                              
Loss on extinguishment of debt         56,000,000us-gaap_GainsLossesOnExtinguishmentOfDebt
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes10Point0PercentDue2018Member		                                                                                        
Senior Notes 11 Point 875 Percent Due 2019 [Member]                                                                                                  
Long-term debt                                                                                                  
Debt instrument, stated interest rate (as a percent) 11.875%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes11Point875PercentDue2019Member		               11.875%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes11Point875PercentDue2019Member		                 11.875%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes11Point875PercentDue2019Member		                                                              
Future contractual maturities of long-term debt and capital leases (excluding issue discounts, premiums and fair value adjustments)                                                                                                  
Long-term Debt, Gross 0us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes11Point875PercentDue2019Member		       605,000,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes11Point875PercentDue2019Member		       0us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes11Point875PercentDue2019Member		 605,000,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes11Point875PercentDue2019Member		                                                                              
Senior Notes 11 Point 875 Percent Due 2019 [Member] | Level 3 Communications, Inc.                                                                                                  
Long-term debt                                                                                                  
Debt Instrument, Face Amount                                                           605,000,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes11Point875PercentDue2019Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember		                       0us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes11Point875PercentDue2019Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember		              
Debt instrument, stated interest rate (as a percent) 11.875%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes11Point875PercentDue2019Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember		               11.875%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes11Point875PercentDue2019Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember		                                                                                
Debt Instrument, Redemption Price, Percentage 106.859%us-gaap_DebtInstrumentRedemptionPricePercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes11Point875PercentDue2019Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember		                                                                                                
Debt Instrument, Unamortized Discount                                                           11,000,000us-gaap_DebtInstrumentUnamortizedDiscount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes11Point875PercentDue2019Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember		                                      
Debt Instrument, Unamortized Debt Issuance Costs                                                           8,000,000us-gaap_UnamortizedDebtIssuanceExpense
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes11Point875PercentDue2019Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember		                                      
Loss on extinguishment of debt (53,000,000)us-gaap_GainsLossesOnExtinguishmentOfDebt
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes11Point875PercentDue2019Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember		                                                                                                
Debt instrument, redemption price of principal amount (as percent)                                                           98.173%lvlt_DebtInstrumentRedemptionPriceAsPercentageOfPrincipalAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes11Point875PercentDue2019Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember		                                      
Debt instrument, issuance transactions (number)                                                           2lvlt_DebtInstrumentIssuanceTransactionsNumber
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes11Point875PercentDue2019Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember		                                      
Senior Notes due 2019 (9.375%)                                                                                                  
Long-term debt                                                                                                  
Debt instrument, stated interest rate (as a percent) 9.375%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes9Point375PercentDue2019Member		               9.375%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes9Point375PercentDue2019Member		                 9.375%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes9Point375PercentDue2019Member		                                                              
Future contractual maturities of long-term debt and capital leases (excluding issue discounts, premiums and fair value adjustments)                                                                                                  
Long-term Debt, Gross 500,000,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes9Point375PercentDue2019Member		       500,000,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes9Point375PercentDue2019Member		       500,000,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes9Point375PercentDue2019Member		 500,000,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes9Point375PercentDue2019Member		                                                                              
Senior Notes due 2019 (9.375%) | Level 3 Financing [Member]                                                                                                  
Long-term debt                                                                                                  
Debt Instrument, Face Amount                                                                                     500,000,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes9Point375PercentDue2019Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		            
Debt instrument, stated interest rate (as a percent) 9.375%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes9Point375PercentDue2019Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		               9.375%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes9Point375PercentDue2019Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                                                                                
Debt Instrument, Unamortized Discount 6,000,000us-gaap_DebtInstrumentUnamortizedDiscount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes9Point375PercentDue2019Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		               6,000,000us-gaap_DebtInstrumentUnamortizedDiscount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes9Point375PercentDue2019Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                                                                   10,000,000us-gaap_DebtInstrumentUnamortizedDiscount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes9Point375PercentDue2019Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		            
Debt Instrument, Unamortized Debt Issuance Costs 7,000,000us-gaap_UnamortizedDebtIssuanceExpense
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes9Point375PercentDue2019Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		               7,000,000us-gaap_UnamortizedDebtIssuanceExpense
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes9Point375PercentDue2019Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                                                                   11,000,000us-gaap_UnamortizedDebtIssuanceExpense
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes9Point375PercentDue2019Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		            
Debt instrument issuance price as a percentage of the principal amount (as a percent)                 98.001%lvlt_DebtInstrumentIssuancePriceasPercentageofPrincipalAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes9Point375PercentDue2019Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                                                                                
Senior Notes due 2019 (9.375%) | Level 3 Financing [Member] | Twelve Months Beginning April 1, 2015                                                                                                  
Long-term debt                                                                                                  
Debt instrument, redemption price of principal amount (as percent)                 104.688%lvlt_DebtInstrumentRedemptionPriceAsPercentageOfPrincipalAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes9Point375PercentDue2019Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_TwelveMonthsBeginningApril12015Member		                                                                                
Senior Notes due 2019 (9.375%) | Level 3 Financing [Member] | Twelve Months Beginning April 1, 2016                                                                                                  
Long-term debt                                                                                                  
Debt instrument, redemption price of principal amount (as percent)                 102.344%lvlt_DebtInstrumentRedemptionPriceAsPercentageOfPrincipalAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes9Point375PercentDue2019Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_TwelveMonthsBeginningApril12016Member		                                                                                
Senior Notes due 2019 (9.375%) | Level 3 Financing [Member] | Twelve Months Beginning April 1, 2017                                                                                                  
Long-term debt                                                                                                  
Debt instrument, redemption price of principal amount (as percent)                 100.00%lvlt_DebtInstrumentRedemptionPriceAsPercentageOfPrincipalAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes9Point375PercentDue2019Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_TwelveMonthsBeginningApril12017Member		                                                                                
Senior Notes due 2019 (9.375%) | Level 3 Financing [Member] | Prior to April 2015                                                                                                  
Long-term debt                                                                                                  
Debt instrument, redemption price of principal amount (as percent)                 100.00%lvlt_DebtInstrumentRedemptionPriceAsPercentageOfPrincipalAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes9Point375PercentDue2019Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriorToApril2015Member		                                                                                
Senior Notes due 2019 (8.125%)                                                                                                  
Long-term debt                                                                                                  
Debt instrument, stated interest rate (as a percent) 8.125%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point125PercentDue2019Member		               8.125%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point125PercentDue2019Member		                 8.125%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point125PercentDue2019Member		                                                              
Future contractual maturities of long-term debt and capital leases (excluding issue discounts, premiums and fair value adjustments)                                                                                                  
Long-term Debt, Gross 1,200,000,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point125PercentDue2019Member		       1,200,000,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point125PercentDue2019Member		       1,200,000,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point125PercentDue2019Member		 1,200,000,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point125PercentDue2019Member		                                                                              
Senior Notes due 2019 (8.125%) | Level 3 Financing [Member]                                                                                                  
Long-term debt                                                                                                  
Debt Instrument, Face Amount                                                                                       1,200,000,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point125PercentDue2019Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		          
Debt instrument, stated interest rate (as a percent) 8.125%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point125PercentDue2019Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		               8.125%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point125PercentDue2019Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                                                                                
Debt Instrument, Unamortized Discount 6,000,000us-gaap_DebtInstrumentUnamortizedDiscount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point125PercentDue2019Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		               6,000,000us-gaap_DebtInstrumentUnamortizedDiscount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point125PercentDue2019Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                                                                                
Debt Instrument, Unamortized Debt Issuance Costs 22,000,000us-gaap_UnamortizedDebtIssuanceExpense
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point125PercentDue2019Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		               22,000,000us-gaap_UnamortizedDebtIssuanceExpense
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point125PercentDue2019Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                                                             32,000,000us-gaap_UnamortizedDebtIssuanceExpense
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point125PercentDue2019Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                  
Senior Notes due 2019 (8.125%) | Level 3 Financing [Member] | Twelve Months Beginning July 1, 2015                                                                                                  
Long-term debt                                                                                                  
Debt instrument, redemption price of principal amount (as percent)                 104.063%lvlt_DebtInstrumentRedemptionPriceAsPercentageOfPrincipalAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point125PercentDue2019Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_TwelveMonthsBeginningJuly12015Member		                                                                                
Senior Notes due 2019 (8.125%) | Level 3 Financing [Member] | Twelve Months Beginning July 1, 2016                                                                                                  
Long-term debt                                                                                                  
Debt instrument, redemption price of principal amount (as percent)                 102.031%lvlt_DebtInstrumentRedemptionPriceAsPercentageOfPrincipalAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point125PercentDue2019Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_TwelveMonthsBeginningJuly12016Member		                                                                                
Senior Notes due 2019 (8.125%) | Level 3 Financing [Member] | Twelve Months Beginning July 1, 2017                                                                                                  
Long-term debt                                                                                                  
Debt instrument, redemption price of principal amount (as percent)                 100.00%lvlt_DebtInstrumentRedemptionPriceAsPercentageOfPrincipalAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point125PercentDue2019Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_TwelveMonthsBeginningJuly12017Member		                                                                                
Senior Notes due 2019 (8.125%) | Level 3 Financing [Member] | Prior to July 2015                                                                                                  
Long-term debt                                                                                                  
Debt instrument, redemption price of principal amount (as percent)                 100.00%lvlt_DebtInstrumentRedemptionPriceAsPercentageOfPrincipalAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point125PercentDue2019Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriorToJuly2015Member		                                                                                
Debt instrument, redemption period notice minimum (number of days)                 30lvlt_DebtInstrumentRedemptionPeriodNoticeMinimumNumberOfDays
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point125PercentDue2019Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriorToJuly2015Member		                                                                                
Debt instrument, redemption period notice maximum (number of days)                 60lvlt_DebtInstrumentRedemptionPeriodNoticeMaximumNumberOfDays
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point125PercentDue2019Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriorToJuly2015Member		                                                                                
Senior Notes due 2019 (8.125%) | Level 3 Escrow Inc [Member]                                                                                                  
Long-term debt                                                                                                  
Debt Instrument, Face Amount                                                                                         600,000,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point125PercentDue2019Member
/ dei_LegalEntityAxis
= lvlt_Level3EscrowIncMember		        
Debt Instrument, Additional Borrowings                                                             600,000,000us-gaap_ProceedsFromIssuanceOfDebt
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point125PercentDue2019Member
/ dei_LegalEntityAxis
= lvlt_Level3EscrowIncMember		                                    
Debt instrument, stated interest rate (as a percent)                                                                                         8.125%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point125PercentDue2019Member
/ dei_LegalEntityAxis
= lvlt_Level3EscrowIncMember		        
Debt Instrument, Unamortized Discount                                                             9,000,000us-gaap_DebtInstrumentUnamortizedDiscount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point125PercentDue2019Member
/ dei_LegalEntityAxis
= lvlt_Level3EscrowIncMember		                           4,000,000us-gaap_DebtInstrumentUnamortizedDiscount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point125PercentDue2019Member
/ dei_LegalEntityAxis
= lvlt_Level3EscrowIncMember		        
Debt instrument, redemption price of principal amount (as percent)                                                             98.545%lvlt_DebtInstrumentRedemptionPriceAsPercentageOfPrincipalAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point125PercentDue2019Member
/ dei_LegalEntityAxis
= lvlt_Level3EscrowIncMember		 99.264%lvlt_DebtInstrumentRedemptionPriceAsPercentageOfPrincipalAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point125PercentDue2019Member
/ dei_LegalEntityAxis
= lvlt_Level3EscrowIncMember		                                  
Senior Notes due 2019 (8.875%)                                                                                                  
Long-term debt                                                                                                  
Debt instrument, stated interest rate (as a percent) 8.875%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point875PercentDue2019Member		               8.875%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point875PercentDue2019Member		                                                                                
Future contractual maturities of long-term debt and capital leases (excluding issue discounts, premiums and fair value adjustments)                                                                                                  
Long-term Debt, Gross 300,000,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point875PercentDue2019Member		       300,000,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point875PercentDue2019Member		       300,000,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point875PercentDue2019Member		 300,000,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point875PercentDue2019Member		                                                                              
Senior Notes due 2019 (8.875%) | Level 3 Communications, Inc.                                                                                                  
Long-term debt                                                                                                  
Debt Instrument, Face Amount                                 300,000,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point875PercentDue2019Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember		                                                                
Debt instrument, stated interest rate (as a percent) 8.875%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point875PercentDue2019Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember		               8.875%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point875PercentDue2019Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember		                                                                                
Debt Instrument, Unamortized Debt Issuance Costs 5,000,000us-gaap_UnamortizedDebtIssuanceExpense
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point875PercentDue2019Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember		               5,000,000us-gaap_UnamortizedDebtIssuanceExpense
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point875PercentDue2019Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember		               7,000,000us-gaap_UnamortizedDebtIssuanceExpense
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point875PercentDue2019Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember		                                                                
Debt instrument, redemption price of principal amount (as percent)                             100.00%lvlt_DebtInstrumentRedemptionPriceAsPercentageOfPrincipalAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point875PercentDue2019Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember		                                                                    
Senior Notes due 2019 (8.875%) | Level 3 Communications, Inc. | Twelve Months Beginning June 1, 2016 [Member]                                                                                                  
Long-term debt                                                                                                  
Debt instrument, redemption price of principal amount (as percent)                 102.219%lvlt_DebtInstrumentRedemptionPriceAsPercentageOfPrincipalAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point875PercentDue2019Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_TwelveMonthsBeginningJune12016Member		                                                                                
Senior Notes due 2019 (8.875%) | Level 3 Communications, Inc. | Twelve Months Beginning June 1, 2015                                                                                                  
Long-term debt                                                                                                  
Debt instrument, redemption price of principal amount (as percent)                 104.438%lvlt_DebtInstrumentRedemptionPriceAsPercentageOfPrincipalAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point875PercentDue2019Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_TwelveMonthsBeginningJune12015Member		                                                                                
Senior Notes due 2019 (8.875%) | Level 3 Communications, Inc. | Twelve Months Beginning June 1, 2017                                                                                                  
Long-term debt                                                                                                  
Debt instrument, redemption price of principal amount (as percent)                 100.00%lvlt_DebtInstrumentRedemptionPriceAsPercentageOfPrincipalAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point875PercentDue2019Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_TwelveMonthsBeginningJune12017Member		                                                                                
Senior Notes due 2019 (8.875%) | Level 3 Communications, Inc. | Prior to June 2015                                                                                                  
Long-term debt                                                                                                  
Debt instrument, redemption price of principal amount (as percent)                 100.00%lvlt_DebtInstrumentRedemptionPriceAsPercentageOfPrincipalAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point875PercentDue2019Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriorToJune2015Member		                                                                                
Debt instrument, redemption minimum gross proceeds from equity offering ($100 million)                 100,000,000lvlt_DebtInstrumentRedemptionMinimumGrossProceedsFromEquityOffering
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point875PercentDue2019Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriorToJune2015Member		                                                                                
Debt instrument, redemption with net proceeds from equity offerings of original principal (as percent)                 35.00%lvlt_DebtInstrumentRedemptionWithNetProceedsFromEquityOfferingsAsPercentageOfOriginalPrincipal
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point875PercentDue2019Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriorToJune2015Member		                                                                                
Debt instrument, redemption price with net proceeds from equity offerings of original principal (as percent)                 108.875%lvlt_DebtInstrumentRedemptionPriceWithNetProceedsFromEquityOfferingsAsPercentageOfOriginalPrincipal
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point875PercentDue2019Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriorToJune2015Member		                                                                                
Debt instrument, minimum percentage of original principal amount outstanding after redemption from equity offerings (as percent) 65.00%lvlt_DebtInstrumentMinimumPercentageOfOriginalPrincipalAmountOutstandingAfterRedemptionFromEquityOfferings
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point875PercentDue2019Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriorToJune2015Member		               65.00%lvlt_DebtInstrumentMinimumPercentageOfOriginalPrincipalAmountOutstandingAfterRedemptionFromEquityOfferings
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point875PercentDue2019Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriorToJune2015Member		                                                                                
Debt instrument, redemption period maximum following receipt of proceeds from equity offerings (number of days)                 90lvlt_DebtInstrumentRedemptionPeriodMaximumFollowingReceiptOfProceedsFromEquityOfferings
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point875PercentDue2019Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriorToJune2015Member		                                                                                
Debt instrument, redemption period notice minimum (number of days)                 30lvlt_DebtInstrumentRedemptionPeriodNoticeMinimumNumberOfDays
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point875PercentDue2019Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriorToJune2015Member		                                                                                
Debt instrument, redemption period notice maximum (number of days)                 60lvlt_DebtInstrumentRedemptionPeriodNoticeMaximumNumberOfDays
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point875PercentDue2019Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriorToJune2015Member		                                                                                
Senior Notes due 2020 (8.625%)                                                                                                  
Long-term debt                                                                                                  
Debt instrument, stated interest rate (as a percent) 8.625%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point625PercentDue2020Member		               8.625%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point625PercentDue2020Member		                                                                                
Future contractual maturities of long-term debt and capital leases (excluding issue discounts, premiums and fair value adjustments)                                                                                                  
Long-term Debt, Gross 900,000,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point625PercentDue2020Member		       900,000,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point625PercentDue2020Member		       900,000,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point625PercentDue2020Member		 900,000,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point625PercentDue2020Member		                                                                              
Senior Notes due 2020 (8.625%) | Level 3 Financing [Member]                                                                                                  
Long-term debt                                                                                                  
Debt Instrument, Face Amount                                                                                           900,000,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point625PercentDue2020Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		      
Debt instrument, stated interest rate (as a percent) 8.625%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point625PercentDue2020Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		               8.625%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point625PercentDue2020Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                                                                                
Debt Instrument, Unamortized Debt Issuance Costs 14,000,000us-gaap_UnamortizedDebtIssuanceExpense
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point625PercentDue2020Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		               14,000,000us-gaap_UnamortizedDebtIssuanceExpense
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point625PercentDue2020Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                                                                         20,000,000us-gaap_UnamortizedDebtIssuanceExpense
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point625PercentDue2020Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		      
Senior Notes due 2020 (8.625%) | Level 3 Financing [Member] | Twelve Months Beginning January 15, 2016                                                                                                  
Long-term debt                                                                                                  
Debt instrument, redemption price of principal amount (as percent)                 104.313%lvlt_DebtInstrumentRedemptionPriceAsPercentageOfPrincipalAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point625PercentDue2020Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_TwelveMonthsBeginningJanuary152016Member		                                                                                
Senior Notes due 2020 (8.625%) | Level 3 Financing [Member] | Twelve Months Beginning January 15, 2017                                                                                                  
Long-term debt                                                                                                  
Debt instrument, redemption price of principal amount (as percent)                 102.156%lvlt_DebtInstrumentRedemptionPriceAsPercentageOfPrincipalAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point625PercentDue2020Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_TwelveMonthsBeginningJanuary152017Member		                                                                                
Senior Notes due 2020 (8.625%) | Level 3 Financing [Member] | Twelve Months Beginning January 15, 2018                                                                                                  
Long-term debt                                                                                                  
Debt instrument, redemption price of principal amount (as percent)                 100.00%lvlt_DebtInstrumentRedemptionPriceAsPercentageOfPrincipalAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point625PercentDue2020Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_TwelveMonthsBeginningJanuary152018Member		                                                                                
Senior Notes due 2020 (8.625%) | Level 3 Financing [Member] | Prior to January 2016                                                                                                  
Long-term debt                                                                                                  
Debt instrument, redemption price of principal amount (as percent)                 100.00%lvlt_DebtInstrumentRedemptionPriceAsPercentageOfPrincipalAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point625PercentDue2020Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriorToJanuary2016Member		                                                                                
Debt instrument, redemption period notice minimum (number of days)                 30lvlt_DebtInstrumentRedemptionPeriodNoticeMinimumNumberOfDays
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point625PercentDue2020Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriorToJanuary2016Member		                                                                                
Debt instrument, redemption period notice maximum (number of days)                 60lvlt_DebtInstrumentRedemptionPeriodNoticeMaximumNumberOfDays
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes8Point625PercentDue2020Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriorToJanuary2016Member		                                                                                
Senior Notes 5.375percent Due 2022 [Member]                                                                                                  
Long-term debt                                                                                                  
Debt Instrument, Face Amount 1,000,000,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes5.375percentDue2022Member		               1,000,000,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes5.375percentDue2022Member		                                                                           1,000,000,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes5.375percentDue2022Member		    
Debt instrument, stated interest rate (as a percent) 5.375%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes5.375percentDue2022Member		               5.375%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes5.375percentDue2022Member		                                                                                
Senior Notes 5.375percent Due 2022 [Member] | Level 3 Financing [Member]                                                                                                  
Long-term debt                                                                                                  
Debt instrument, stated interest rate (as a percent) 5.375%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes5.375percentDue2022Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		               5.375%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes5.375percentDue2022Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                                                                                
Debt Instrument, Unamortized Debt Issuance Costs 12,000,000us-gaap_UnamortizedDebtIssuanceExpense
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes5.375percentDue2022Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		               12,000,000us-gaap_UnamortizedDebtIssuanceExpense
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes5.375percentDue2022Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                                                                           17,000,000us-gaap_UnamortizedDebtIssuanceExpense
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes5.375percentDue2022Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		    
Senior Notes 5.375percent Due 2022 [Member] | Level 3 Financing [Member] | Twelve Months Beginning August 15, 2017 [Member]                                                                                                  
Long-term debt                                                                                                  
Debt instrument, redemption price of principal amount (as percent)                 102.688%lvlt_DebtInstrumentRedemptionPriceAsPercentageOfPrincipalAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes5.375percentDue2022Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_TwelveMonthsBeginningAugust152017Member		                                                                                
Senior Notes 5.375percent Due 2022 [Member] | Level 3 Financing [Member] | Twelve Months Beginning August 15, 2018 [Member]                                                                                                  
Long-term debt                                                                                                  
Debt instrument, redemption price of principal amount (as percent)                 101.344%lvlt_DebtInstrumentRedemptionPriceAsPercentageOfPrincipalAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes5.375percentDue2022Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_TwelveMonthsBeginningAugust152018Member		                                                                                
Senior Notes 5.375percent Due 2022 [Member] | Level 3 Financing [Member] | Twelve Months Beginning August 15, 2019 [Member]                                                                                                  
Long-term debt                                                                                                  
Debt instrument, redemption price of principal amount (as percent)                 100.00%lvlt_DebtInstrumentRedemptionPriceAsPercentageOfPrincipalAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes5.375percentDue2022Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_TwelveMonthsBeginningAugust152019Member		                                                                                
Senior Notes 5.375percent Due 2022 [Member] | Level 3 Financing [Member] | Prior To August 15, 2017 [Member]                                                                                                  
Long-term debt                                                                                                  
Debt Instrument Redemption Minimum Gross Proceeds from Private or Public Offering                 100,000,000lvlt_DebtInstrumentRedemptionMinimumGrossProceedsfromPrivateorPublicOffering
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes5.375percentDue2022Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriorToAugust152017Member		                                                                                
Debt instrument, redemption price of principal amount (as percent)                 100.00%lvlt_DebtInstrumentRedemptionPriceAsPercentageOfPrincipalAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes5.375percentDue2022Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriorToAugust152017Member		                                                                                
Debt instrument, minimum percentage of original principal amount outstanding after redemption from equity offerings (as percent) 60.00%lvlt_DebtInstrumentMinimumPercentageOfOriginalPrincipalAmountOutstandingAfterRedemptionFromEquityOfferings
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes5.375percentDue2022Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriorToAugust152017Member		               60.00%lvlt_DebtInstrumentMinimumPercentageOfOriginalPrincipalAmountOutstandingAfterRedemptionFromEquityOfferings
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes5.375percentDue2022Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriorToAugust152017Member		                                                                                
Debt instrument, redemption period maximum following receipt of proceeds from equity offerings (number of days)                 90lvlt_DebtInstrumentRedemptionPeriodMaximumFollowingReceiptOfProceedsFromEquityOfferings
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes5.375percentDue2022Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriorToAugust152017Member		                                                                                
Debt instrument, redemption period notice minimum (number of days)                 30lvlt_DebtInstrumentRedemptionPeriodNoticeMinimumNumberOfDays
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes5.375percentDue2022Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriorToAugust152017Member		                                                                                
Debt instrument, redemption period notice maximum (number of days)                 60lvlt_DebtInstrumentRedemptionPeriodNoticeMaximumNumberOfDays
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes5.375percentDue2022Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriorToAugust152017Member		                                                                                
Senior Notes 5.375percent Due 2022 [Member] | Level 3 Escrow II, Inc. [Member]                                                                                                  
Long-term debt                                                                                                  
Debt Instrument, Face Amount                                                                                             1,000,000,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes5.375percentDue2022Member
/ dei_LegalEntityAxis
= lvlt_Level3EscrowIIInc.Member		    
Senior Notes 5.375percent Due 2022 [Member] | Level 3 Escrow II, Inc. [Member] | Prior To August 15, 2017 [Member]                                                                                                  
Long-term debt                                                                                                  
Debt instrument, redemption with net proceeds from equity offerings of original principal (as percent)                 40.00%lvlt_DebtInstrumentRedemptionWithNetProceedsFromEquityOfferingsAsPercentageOfOriginalPrincipal
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes5.375percentDue2022Member
/ dei_LegalEntityAxis
= lvlt_Level3EscrowIIInc.Member
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriorToAugust152017Member		                                                                                
Debt instrument, redemption price with net proceeds from equity offerings of original principal (as percent)                 105.375%lvlt_DebtInstrumentRedemptionPriceWithNetProceedsFromEquityOfferingsAsPercentageOfOriginalPrincipal
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes5.375percentDue2022Member
/ dei_LegalEntityAxis
= lvlt_Level3EscrowIIInc.Member
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriorToAugust152017Member		                                                                                
Senior Notes 5point75Percent Due 2022 [Member] | Level 3 Communications, Inc.                                                                                                  
Long-term debt                                                                                                  
Debt Instrument, Face Amount                                                                                   600,000,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes5point75PercentDue2022Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember		              
Debt instrument, stated interest rate (as a percent) 5.75%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes5point75PercentDue2022Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember		               5.75%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes5point75PercentDue2022Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember		                                                                                
Debt Instrument, Unamortized Debt Issuance Costs                                                                                             10,000,000us-gaap_UnamortizedDebtIssuanceExpense
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes5point75PercentDue2022Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember		    
Senior Notes 5point75Percent Due 2022 [Member] | Level 3 Communications, Inc. | Twelve Months Beginning June 1, 2016                                                                                                  
Long-term debt                                                                                                  
Debt instrument, redemption price of principal amount (as percent)                 102.875%lvlt_DebtInstrumentRedemptionPriceAsPercentageOfPrincipalAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes5point75PercentDue2022Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_TwelveMonthsBeginningDecember12017Member		                                                                                
Senior Notes 5point75Percent Due 2022 [Member] | Level 3 Communications, Inc. | Twelve Months Beginning December 1, 2018 [Member]                                                                                                  
Long-term debt                                                                                                  
Debt instrument, redemption price of principal amount (as percent)                 101.4375%lvlt_DebtInstrumentRedemptionPriceAsPercentageOfPrincipalAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes5point75PercentDue2022Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_TwelveMonthsBeginningDecember12018Member		                                                                                
Senior Notes 5point75Percent Due 2022 [Member] | Level 3 Communications, Inc. | Prior To December 1, 2017 [Member]                                                                                                  
Long-term debt                                                                                                  
Debt Instrument Redemption Minimum Gross Proceeds from Private or Public Offering                 100,000,000lvlt_DebtInstrumentRedemptionMinimumGrossProceedsfromPrivateorPublicOffering
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes5point75PercentDue2022Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriorToDecember12017Member		                                                                                
Debt instrument, redemption price of principal amount (as percent)                 100.00%lvlt_DebtInstrumentRedemptionPriceAsPercentageOfPrincipalAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes5point75PercentDue2022Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriorToDecember12017Member		                                                                                
Debt instrument, redemption with net proceeds from equity offerings of original principal (as percent)                 40.00%lvlt_DebtInstrumentRedemptionWithNetProceedsFromEquityOfferingsAsPercentageOfOriginalPrincipal
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes5point75PercentDue2022Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriorToDecember12017Member		                                                                                
Debt instrument, redemption price with net proceeds from equity offerings of original principal (as percent)                 105.75%lvlt_DebtInstrumentRedemptionPriceWithNetProceedsFromEquityOfferingsAsPercentageOfOriginalPrincipal
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes5point75PercentDue2022Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriorToDecember12017Member		                                                                                
Debt instrument, minimum percentage of original principal amount outstanding after redemption from equity offerings (as percent) 60.00%lvlt_DebtInstrumentMinimumPercentageOfOriginalPrincipalAmountOutstandingAfterRedemptionFromEquityOfferings
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes5point75PercentDue2022Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriorToDecember12017Member		               60.00%lvlt_DebtInstrumentMinimumPercentageOfOriginalPrincipalAmountOutstandingAfterRedemptionFromEquityOfferings
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes5point75PercentDue2022Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriorToDecember12017Member		                                                                                
Debt instrument, redemption period maximum following receipt of proceeds from equity offerings (number of days)                 90lvlt_DebtInstrumentRedemptionPeriodMaximumFollowingReceiptOfProceedsFromEquityOfferings
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes5point75PercentDue2022Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriorToDecember12017Member		                                                                                
Debt instrument, redemption period notice minimum (number of days)                 30lvlt_DebtInstrumentRedemptionPeriodNoticeMinimumNumberOfDays
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes5point75PercentDue2022Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriorToDecember12017Member		                                                                                
Debt instrument, redemption period notice maximum (number of days)                 60lvlt_DebtInstrumentRedemptionPeriodNoticeMaximumNumberOfDays
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes5point75PercentDue2022Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_PriorToDecember12017Member		                                                                                
Senior Notes 5point75Percent Due 2022 [Member] | Level 3 Communications, Inc. | Twelve Months Beginning December 1, 2019 [Member]                                                                                                  
Long-term debt                                                                                                  
Debt instrument, redemption price of principal amount (as percent)                 100.00%lvlt_DebtInstrumentRedemptionPriceAsPercentageOfPrincipalAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes5point75PercentDue2022Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
/ lvlt_RedemptionOptionByEffectivePeriodAxis
= lvlt_TwelveMonthsBeginningDecember12019Member		                                                                                
Convertible Senior Notes due 2013 (15.0%)                                                                                                  
Long-term debt                                                                                                  
Debt instrument, stated interest rate (as a percent) 15.00%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_ConvertibleSeniorNotes15PercentDue2013Member		               15.00%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_ConvertibleSeniorNotes15PercentDue2013Member		                 15.00%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_ConvertibleSeniorNotes15PercentDue2013Member		                                                              
Convertible Senior Notes 7 Percent Due 2015 [Member]                                                                                                  
Long-term debt                                                                                                  
Debt instrument, stated interest rate (as a percent) 7.00%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_ConvertibleSeniorNotes7PercentDue2015Member		               7.00%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_ConvertibleSeniorNotes7PercentDue2015Member		                 7.00%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_ConvertibleSeniorNotes7PercentDue2015Member		                                                              
Debt Conversion, Original Debt, Amount 142,000,000us-gaap_DebtConversionOriginalDebtAmount1
/ us-gaap_DebtInstrumentAxis
= lvlt_ConvertibleSeniorNotes7PercentDue2015Member		                                                                                                
Debt Conversion, Converted Instrument, Amount 1,000us-gaap_DebtConversionConvertedInstrumentAmount1
/ us-gaap_DebtInstrumentAxis
= lvlt_ConvertibleSeniorNotes7PercentDue2015Member		                                                                                                
Debt conversion, shares issued upon conversion (in shares) 5,000,000us-gaap_DebtConversionConvertedInstrumentSharesIssued1
/ us-gaap_DebtInstrumentAxis
= lvlt_ConvertibleSeniorNotes7PercentDue2015Member		                                                                                                
Conversion of Stock, Shares Converted 37us-gaap_ConversionOfStockSharesConverted1
/ us-gaap_DebtInstrumentAxis
= lvlt_ConvertibleSeniorNotes7PercentDue2015Member		                                                                                                
Future contractual maturities of long-term debt and capital leases (excluding issue discounts, premiums and fair value adjustments)                                                                                                  
Long-term Debt, Gross 58,000,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_ConvertibleSeniorNotes7PercentDue2015Member		       200,000,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_ConvertibleSeniorNotes7PercentDue2015Member		       58,000,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_ConvertibleSeniorNotes7PercentDue2015Member		 200,000,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_ConvertibleSeniorNotes7PercentDue2015Member		                                                                              
Convertible Senior Notes 7 Percent Due 2015 [Member] | Level 3 Communications, Inc.                                                                                                  
Long-term debt                                                                                                  
Debt Instrument, Face Amount                       200,000,000us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_ConvertibleSeniorNotes7PercentDue2015Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember		                                                                          
Debt Instrument, Additional Borrowings                                                                 275,000,000us-gaap_ProceedsFromIssuanceOfDebt
/ us-gaap_DebtInstrumentAxis
= lvlt_ConvertibleSeniorNotes7PercentDue2015Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember		                                
Debt instrument, stated interest rate (as a percent) 7.00%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_ConvertibleSeniorNotes7PercentDue2015Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember		               7.00%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_ConvertibleSeniorNotes7PercentDue2015Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember		                                                                                
Debt Instrument, Unamortized Debt Issuance Costs 0us-gaap_UnamortizedDebtIssuanceExpense
/ us-gaap_DebtInstrumentAxis
= lvlt_ConvertibleSeniorNotes7PercentDue2015Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember		               0us-gaap_UnamortizedDebtIssuanceExpense
/ us-gaap_DebtInstrumentAxis
= lvlt_ConvertibleSeniorNotes7PercentDue2015Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember		     4,000,000us-gaap_UnamortizedDebtIssuanceExpense
/ us-gaap_DebtInstrumentAxis
= lvlt_ConvertibleSeniorNotes7PercentDue2015Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember		                                                                          
Debt Instrument, Principal amount used for conversion 1,000lvlt_DebtInstrumentConvertiblePerPrincipalAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_ConvertibleSeniorNotes7PercentDue2015Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember		               1,000lvlt_DebtInstrumentConvertiblePerPrincipalAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_ConvertibleSeniorNotes7PercentDue2015Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember		                                                                                
Debt instrument, redemption price of principal amount (as percent)                 100.00%lvlt_DebtInstrumentRedemptionPriceAsPercentageOfPrincipalAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_ConvertibleSeniorNotes7PercentDue2015Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember		                                                                                
Debt instrument, convertible, conversion (price per share) $ 27us-gaap_DebtInstrumentConvertibleConversionPrice1
/ us-gaap_DebtInstrumentAxis
= lvlt_ConvertibleSeniorNotes7PercentDue2015Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember		               $ 27us-gaap_DebtInstrumentConvertibleConversionPrice1
/ us-gaap_DebtInstrumentAxis
= lvlt_ConvertibleSeniorNotes7PercentDue2015Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember		                                                                                
Debt instrument, number of shares converted for each $1000 principal amount (in shares) 37lvlt_DebtInstrumentConvertibleNumberOfSharesPerPrincipalAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_ConvertibleSeniorNotes7PercentDue2015Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember		               37lvlt_DebtInstrumentConvertibleNumberOfSharesPerPrincipalAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_ConvertibleSeniorNotes7PercentDue2015Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember		                                                                                
Convertible Senior Notes due 2015 Series B (7.0%)                                                                                                  
Long-term debt                                                                                                  
Debt instrument, stated interest rate (as a percent) 7.00%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_ConvertibleSeniorNotes7PercentDue2015SeriesBMember		               7.00%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_ConvertibleSeniorNotes7PercentDue2015SeriesBMember		                 7.00%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_ConvertibleSeniorNotes7PercentDue2015SeriesBMember		                                                              
Future contractual maturities of long-term debt and capital leases (excluding issue discounts, premiums and fair value adjustments)                                                                                                  
Long-term Debt, Gross 275,000,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_ConvertibleSeniorNotes7PercentDue2015SeriesBMember		       275,000,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_ConvertibleSeniorNotes7PercentDue2015SeriesBMember		       275,000,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_ConvertibleSeniorNotes7PercentDue2015SeriesBMember		 275,000,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_ConvertibleSeniorNotes7PercentDue2015SeriesBMember		                                                                              
Convertible Senior Notes due 2015 Series B (7.0%) | Level 3 Communications, Inc.                                                                                                  
Long-term debt                                                                                                  
Debt instrument, stated interest rate (as a percent) 7.00%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_ConvertibleSeniorNotes7PercentDue2015SeriesBMember
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember		               7.00%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_ConvertibleSeniorNotes7PercentDue2015SeriesBMember
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember		                                                                                
Convertible Senior Notes due 2016 (6.5%)                                                                                                  
Long-term debt                                                                                                  
Debt instrument, stated interest rate (as a percent) 6.50%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_ConvertibleSeniorNotes6Point5PercentDue2016Member		               6.50%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_ConvertibleSeniorNotes6Point5PercentDue2016Member		                 6.50%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_ConvertibleSeniorNotes6Point5PercentDue2016Member		                                                              
Convertible Subordinated Notes due 2010 (6.0%) | Level 3 Communications, Inc.                                                                                                  
Long-term debt                                                                                                  
Debt instrument, stated interest rate (as a percent)                       6.00%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_ConvertibleSubordinatedNotes6PercentDue2010Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember		                                                                          
Debt Instrument, Principal amount exchanged                       142,000,000us-gaap_DebtInstrumentIncreaseDecreaseOtherNet
/ us-gaap_DebtInstrumentAxis
= lvlt_ConvertibleSubordinatedNotes6PercentDue2010Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember		                                                                          
Convertible Senior Notes due 2010 (2.875%) | Level 3 Communications, Inc.                                                                                                  
Long-term debt                                                                                                  
Debt instrument, stated interest rate (as a percent)                       2.875%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_ConvertibleSeniorNotes2Point875PercentDue2010Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember		                                                                          
Debt Instrument, Principal amount exchanged                       140,000,000us-gaap_DebtInstrumentIncreaseDecreaseOtherNet
/ us-gaap_DebtInstrumentAxis
= lvlt_ConvertibleSeniorNotes2Point875PercentDue2010Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember		                                                                          
Convertible Senior Notes due 2011 (5.25%) | Level 3 Communications, Inc.                                                                                                  
Long-term debt                                                                                                  
Debt instrument, stated interest rate (as a percent)                                                                                               5.25%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_ConvertibleSeniorNotes5Point25PercentDue2011Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember		  
Convertible Senior Notes due 2012 (3.5%) | Level 3 Communications, Inc.                                                                                                  
Long-term debt                                                                                                  
Debt instrument, stated interest rate (as a percent) 3.50%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_ConvertibleSeniorNotes3Point5PercentDue2012Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember		               3.50%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_ConvertibleSeniorNotes3Point5PercentDue2012Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember		                                                                                
Repayments of Long-term Debt                                   274,000,000us-gaap_RepaymentsOfLongTermDebt
/ us-gaap_DebtInstrumentAxis
= lvlt_ConvertibleSeniorNotes3Point5PercentDue2012Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember		                                                              
Convertible Senior Discount Notes due 2013 (9.0%) | Level 3 Communications, Inc.                                                                                                  
Long-term debt                                                                                                  
Debt instrument, stated interest rate (as a percent) 9.00%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_ConvertibleSeniorDiscountNotes9PercentDue2013Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember		               9.00%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_ConvertibleSeniorDiscountNotes9PercentDue2013Member
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember		                                                                                
Commercial Mortgage due 2015 (9.86%)                                                                                                  
Long-term debt                                                                                                  
Debt instrument, stated interest rate (as a percent)                                   9.86%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_CommercialMortgage9Point86PercentDue2015Member		                                                              
Capital Leases                                                                                                  
Long-term debt                                                                                                  
Debt instrument, weighted average interest rate (as percent) 6.20%us-gaap_DebtWeightedAverageInterestRate
/ us-gaap_DebtInstrumentAxis
= us-gaap_CapitalLeaseObligationsMember		       9.20%us-gaap_DebtWeightedAverageInterestRate
/ us-gaap_DebtInstrumentAxis
= us-gaap_CapitalLeaseObligationsMember		       6.20%us-gaap_DebtWeightedAverageInterestRate
/ us-gaap_DebtInstrumentAxis
= us-gaap_CapitalLeaseObligationsMember		 9.20%us-gaap_DebtWeightedAverageInterestRate
/ us-gaap_DebtInstrumentAxis
= us-gaap_CapitalLeaseObligationsMember		                                                                              
Future contractual maturities of long-term debt and capital leases (excluding issue discounts, premiums and fair value adjustments)                                                                                                  
Total Debt Obligations 207,000,000lvlt_DebtInstrumentAndCapitalLeaseObligationsCarryingAmount
/ us-gaap_DebtInstrumentAxis
= us-gaap_CapitalLeaseObligationsMember		               207,000,000lvlt_DebtInstrumentAndCapitalLeaseObligationsCarryingAmount
/ us-gaap_DebtInstrumentAxis
= us-gaap_CapitalLeaseObligationsMember		                                                                                
Long-term Debt, Gross 207,000,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= us-gaap_CapitalLeaseObligationsMember		       73,000,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= us-gaap_CapitalLeaseObligationsMember		       207,000,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= us-gaap_CapitalLeaseObligationsMember		 73,000,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= us-gaap_CapitalLeaseObligationsMember		                                                                              
Other                                                                                                  
Long-term debt                                                                                                  
Debt instrument, weighted average interest rate (as percent) 5.00%us-gaap_DebtWeightedAverageInterestRate
/ us-gaap_DebtInstrumentAxis
= lvlt_DebtInstrumentOtherMember		       4.00%us-gaap_DebtWeightedAverageInterestRate
/ us-gaap_DebtInstrumentAxis
= lvlt_DebtInstrumentOtherMember		       5.00%us-gaap_DebtWeightedAverageInterestRate
/ us-gaap_DebtInstrumentAxis
= lvlt_DebtInstrumentOtherMember		 4.00%us-gaap_DebtWeightedAverageInterestRate
/ us-gaap_DebtInstrumentAxis
= lvlt_DebtInstrumentOtherMember		                                                                              
Future contractual maturities of long-term debt and capital leases (excluding issue discounts, premiums and fair value adjustments)                                                                                                  
Total Debt Obligations 1,000,000lvlt_DebtInstrumentAndCapitalLeaseObligationsCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_DebtInstrumentOtherMember		               1,000,000lvlt_DebtInstrumentAndCapitalLeaseObligationsCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_DebtInstrumentOtherMember		                                                                                
Long-term Debt, Gross 0us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_DebtInstrumentOtherMember		       13,000,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_DebtInstrumentOtherMember		       0us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_DebtInstrumentOtherMember		 13,000,000us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= lvlt_DebtInstrumentOtherMember		                                                                              
Other | Level 3 Financing [Member]                                                                                                  
Long-term debt                                                                                                  
Repayments of Long-term Debt                             15,000,000us-gaap_RepaymentsOfLongTermDebt
/ us-gaap_DebtInstrumentAxis
= lvlt_DebtInstrumentOtherMember
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember		                                                                    
London Interbank Offered Rate (LIBOR) [Member] | Tranche B 2022 Term Loans [Member] | Guarantor Subsidiaries [Member]                                                                                                  
Long-term debt                                                                                                  
Debt instrument, Interest spread on debt (as percent) 3.50%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheB2022TermLoansMember
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember
/ us-gaap_VariableRateAxis
= us-gaap_LondonInterbankOfferedRateLIBORMember		                                                                                                
London Interbank Offered Rate (LIBOR) [Member] | Tranche B 2022 Term Loans [Member] | Guarantor Subsidiaries [Member] | Minimum [Member]                                                                                                  
Long-term debt                                                                                                  
Debt instrument, stated interest rate (as a percent)                                                                       1.00%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheB2022TermLoansMember
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
/ us-gaap_VariableRateAxis
= us-gaap_LondonInterbankOfferedRateLIBORMember		                          
London Interbank Offered Rate (LIBOR) [Member] | TrancheB2020TermLoan [Member] | Guarantor Subsidiaries [Member]                                                                                                  
Long-term debt                                                                                                  
Debt instrument, Interest spread on debt (as percent)                                                   3.00%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheB2020TermLoanMember
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember
/ us-gaap_VariableRateAxis
= us-gaap_LondonInterbankOfferedRateLIBORMember		                                              
London Interbank Offered Rate (LIBOR) [Member] | TrancheB2020TermLoan [Member] | Guarantor Subsidiaries [Member] | Minimum [Member]                                                                                                  
Long-term debt                                                                                                  
Debt instrument, stated interest rate (as a percent)                                       1.00%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheB2020TermLoanMember
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
/ us-gaap_VariableRateAxis
= us-gaap_LondonInterbankOfferedRateLIBORMember		         1.00%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheB2020TermLoanMember
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
/ us-gaap_VariableRateAxis
= us-gaap_LondonInterbankOfferedRateLIBORMember		 1.00%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheB2020TermLoanMember
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
/ us-gaap_VariableRateAxis
= us-gaap_LondonInterbankOfferedRateLIBORMember		                                              
London Interbank Offered Rate (LIBOR) [Member] | TrancheBIII2019TermLoan [Member] | Guarantor Subsidiaries [Member]                                                                                                  
Long-term debt                                                                                                  
Debt instrument, Interest spread on debt (as percent)                                               3.00%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheBIII2019TermLoanMember
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember
/ us-gaap_VariableRateAxis
= us-gaap_LondonInterbankOfferedRateLIBORMember		                                                  
London Interbank Offered Rate (LIBOR) [Member] | TrancheBIII2019TermLoan [Member] | Guarantor Subsidiaries [Member] | Minimum [Member]                                                                                                  
Long-term debt                                                                                                  
Debt instrument, stated interest rate (as a percent)                                               1.00%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= lvlt_TrancheBIII2019TermLoanMember
/ dei_LegalEntityAxis
= us-gaap_GuarantorSubsidiariesMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
/ us-gaap_VariableRateAxis
= us-gaap_LondonInterbankOfferedRateLIBORMember		                                                  
Subsequent Event [Member] | Senior Notes due 2019 (9.375%) | Level 3 Financing [Member]                                                                                                  
Long-term debt                                                                                                  
Debt Instrument, Face Amount                                                                                                 500,000,000us-gaap_DebtInstrumentFaceAmount
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Debt instrument, stated interest rate (as a percent)                                                                                                 9.375%us-gaap_DebtInstrumentInterestRateStatedPercentage
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/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember
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= us-gaap_SubsequentEventMember
Loss on extinguishment of debt                                                                   40,000,000us-gaap_GainsLossesOnExtinguishmentOfDebt
/ us-gaap_DebtInstrumentAxis
= lvlt_SeniorNotes9Point375PercentDue2019Member
/ dei_LegalEntityAxis
= lvlt_Level3FinancingMember
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember		                              
Subsequent Event [Member] | Senior Notes 5point 625Percent Due 2023 [Member] | Level 3 Financing [Member]                                                                                                  
Long-term debt                                                                                                  
Debt Instrument, Face Amount                                                                                                 $ 500,000,000us-gaap_DebtInstrumentFaceAmount
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/ dei_LegalEntityAxis
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Debt instrument, stated interest rate (as a percent)                                                                                                 5.625%us-gaap_DebtInstrumentInterestRateStatedPercentage
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[1] *The $2 billion Tranche B Term Loan due 2022 had an interest rate of 4.5% as of December 31, 2014. The $815 million Tranche B-III 2019 Term Loan due 2019 and the $1.796 billion Tranche B 2020 Term Loan due 2020 each had an interest rate of 4.00% as of December 31, 2014.