Income Taxes - Deferred Tax Assets (Liabilities) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Oct. 31, 2014	Dec. 31, 2013
Deferred Tax Assets (Liabilities) [Line Items]
Deferred Tax Liabilities, Intangible Assets		$ 15
Deferred Tax Assets:
Accrued payroll and related benefits	113		132
Deferred revenue	322us-gaap_DeferredTaxAssetsDeferredIncome		336us-gaap_DeferredTaxAssetsDeferredIncome
Unutilized tax net operating loss carry forwards	5,218		4,791
Fixed assets and intangible assets	90		102
Intercompany loss	128lvlt_DeferredTaxAssetIntercompany		139lvlt_DeferredTaxAssetIntercompany
Other	174us-gaap_DeferredTaxAssetsOther		144us-gaap_DeferredTaxAssetsOther
Total Deferred Tax Assets	6,045us-gaap_DeferredTaxAssetsGross		5,644us-gaap_DeferredTaxAssetsGross
Deferred Tax Liabilities:
Fixed assets and intangible assets	(1,371)		(790)
Deferred revenue	(73)		(76)
Other	(59)us-gaap_DeferredTaxLiabilitiesOther		(33)us-gaap_DeferredTaxLiabilitiesOther
Foreign branch income	(130)		(163)
Total Deferred Tax Liabilities	(1,633)us-gaap_DeferredTaxLiabilities		(1,062)us-gaap_DeferredTaxLiabilities
Net Deferred Tax Assets before valuation allowance	4,412lvlt_DeferredTaxAssetsLiabilitiesGross		4,582lvlt_DeferredTaxAssetsLiabilitiesGross
Valuation Allowance	(4,437)		(4,698)
Net Deferred Tax (Liability) Asset after Valuation Allowance	25us-gaap_DeferredTaxAssetsLiabilitiesNet		116us-gaap_DeferredTaxAssetsLiabilitiesNet
Net current deferred income tax asset	8us-gaap_DeferredTaxAssetsNetCurrent		9us-gaap_DeferredTaxAssetsNetCurrent
Net current deferred income tax liability	0us-gaap_DeferredTaxLiabilitiesCurrent		(2)us-gaap_DeferredTaxLiabilitiesCurrent
Net non-current deferred income tax asset	292us-gaap_DeferredTaxAssetsNetNoncurrent		211us-gaap_DeferredTaxAssetsNetNoncurrent
Net non-current deferred income tax liability	(325)		(334)
Deferred Tax Assets, Net of Valuation Allowance		15us-gaap_DeferredTaxAssetsNet
U.S. Internal Revenue Service (IRS)
Deferred Tax Assets (Liabilities) [Line Items]
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount	100
Deferred Tax Liabilities:
Valuation Allowance	(4,400)		(4,700)
Operating Loss Carryforwards	$ 10,304

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Deferred Tax Assets, Goodwill and Intangible Assets, Intangible Assets and Fixed Assets

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Deferred Tax Assets (Liabilities), Gross

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Deferred Tax Liabilities, Goodwill and Intangible Assets, Intangible Assets and Fixed Assets

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from deferred income.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards.

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Amount after allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards, net of deferred tax liability attributable to taxable temporary differences.

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Amount after allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards.

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Amount after allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards expected to be realized or consumed within one year or operating cycle, if longer.

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Amount after allocation of valuation allowances of noncurrent deferred tax asset attributable to deductible temporary differences and carryforwards. Noncurrent assets are expected to be realized or consumed after one year (or the normal operating cycle, if longer).

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible operating loss carryforwards.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences not separately disclosed.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from employee compensation.

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Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized.

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Amount of deferred tax liability attributable to taxable temporary differences net of deferred tax asset attributable to deductible temporary differences and carryforwards after valuation allowances.

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Amount of deferred tax liability attributable to taxable temporary differences, net of deferred tax asset attributable to deductible temporary differences and carryforwards net of valuation allowances expected to be realized or consumed within one year or operating cycle, if longer.

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Amount of deferred tax liability attributable to taxable temporary differences from intangible assets other than goodwill.

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Amount of deferred tax liability attributable to taxable temporary differences not separately disclosed.

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Amount of deferred tax liability attributable to taxable temporary differences from tax deferred revenue or other income not separately disclosed.

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Amount of deferred tax liability attributable to taxable temporary differences from undistributed earnings of subsidiaries and other recognized entities not within the country of domicile of the entity.

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Amount of operating loss carryforward, before tax effects, available to reduce future taxable income under enacted tax laws.

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Amount of increase (decrease) in the valuation allowance for a specified deferred tax asset.

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