Condensed Consolidating Financial Information - Statements of Cash Flows (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended
Jun. 30, 2014	Jun. 30, 2013
Condensed Consolidating Financial Information
Net Cash Provided by (Used in) Operating Activities	$ 444	$ 223
Cash Flows from Investing Activities:
Capital expenditures	(404)	(377)
Decrease in restricted cash and securities, net	2	8
Net Cash Provided by (Used in) Investing Activities	(402)	(383)
Cash Flows from Financing Activities:
Payments on and repurchases of long-term debt, including current portions and refinancing costs	(6)	(199)
Increase (decrease) due from-to affiliates, net	0	0
Net Cash Provided by (Used in) Financing Activities	(6)	(199)
Effect of Exchange Rates on Cash and Cash Equivalents	(30)	(24)
Net Change in Cash and Cash Equivalents	6	(383)
Cash and Cash Equivalents at Beginning of Period	631	979
Cash and Cash Equivalents at End of Period	637	596
Payments for (Proceeds from) Other Investing Activities	0	14
Level 3 Communications, Inc.
Condensed Consolidating Financial Information
Net Cash Provided by (Used in) Operating Activities	(66)	(86)
Cash Flows from Investing Activities:
Capital expenditures	0	0
Decrease in restricted cash and securities, net	0	5
Net Cash Provided by (Used in) Investing Activities	0	5
Cash Flows from Financing Activities:
Payments on and repurchases of long-term debt, including current portions and refinancing costs	0	(172)
Increase (decrease) due from-to affiliates, net	66	9
Net Cash Provided by (Used in) Financing Activities	66	(163)
Effect of Exchange Rates on Cash and Cash Equivalents	0	0
Net Change in Cash and Cash Equivalents	0	(244)
Cash and Cash Equivalents at Beginning of Period	8	253
Cash and Cash Equivalents at End of Period	8	9
Payments for (Proceeds from) Other Investing Activities		0
Level 3 Financing, Inc.
Condensed Consolidating Financial Information
Net Cash Provided by (Used in) Operating Activities	(222)	(269)
Cash Flows from Investing Activities:
Capital expenditures	0	0
Decrease in restricted cash and securities, net	0	0
Net Cash Provided by (Used in) Investing Activities	0	0
Cash Flows from Financing Activities:
Payments on and repurchases of long-term debt, including current portions and refinancing costs	0	(3)
Increase (decrease) due from-to affiliates, net	222	272
Net Cash Provided by (Used in) Financing Activities	222	269
Effect of Exchange Rates on Cash and Cash Equivalents	0	0
Net Change in Cash and Cash Equivalents	0	0
Cash and Cash Equivalents at Beginning of Period	6	5
Cash and Cash Equivalents at End of Period	6	5
Payments for (Proceeds from) Other Investing Activities		0
Level 3 Communications, LLC
Condensed Consolidating Financial Information
Net Cash Provided by (Used in) Operating Activities	370	74
Cash Flows from Investing Activities:
Capital expenditures	(192)	(159)
Decrease in restricted cash and securities, net	0	0
Net Cash Provided by (Used in) Investing Activities	(192)	(159)
Cash Flows from Financing Activities:
Payments on and repurchases of long-term debt, including current portions and refinancing costs	0	(4)
Increase (decrease) due from-to affiliates, net	(111)	60
Net Cash Provided by (Used in) Financing Activities	(111)	56
Effect of Exchange Rates on Cash and Cash Equivalents	0	0
Net Change in Cash and Cash Equivalents	67	(29)
Cash and Cash Equivalents at Beginning of Period	347	386
Cash and Cash Equivalents at End of Period	414	357
Payments for (Proceeds from) Other Investing Activities		0
Other Non-Guarantor Subsidiaries
Condensed Consolidating Financial Information
Net Cash Provided by (Used in) Operating Activities	362	504
Cash Flows from Investing Activities:
Capital expenditures	(212)	(218)
Decrease in restricted cash and securities, net	2	3
Net Cash Provided by (Used in) Investing Activities	(210)	(229)
Cash Flows from Financing Activities:
Payments on and repurchases of long-term debt, including current portions and refinancing costs	(6)	(20)
Increase (decrease) due from-to affiliates, net	(177)	(341)
Net Cash Provided by (Used in) Financing Activities	(183)	(361)
Effect of Exchange Rates on Cash and Cash Equivalents	(30)	(24)
Net Change in Cash and Cash Equivalents	(61)	(110)
Cash and Cash Equivalents at Beginning of Period	270	335
Cash and Cash Equivalents at End of Period	209	225
Payments for (Proceeds from) Other Investing Activities		14
Eliminations
Condensed Consolidating Financial Information
Net Cash Provided by (Used in) Operating Activities	0	0
Cash Flows from Investing Activities:
Capital expenditures	0	0
Decrease in restricted cash and securities, net	0	0
Net Cash Provided by (Used in) Investing Activities	0	0
Cash Flows from Financing Activities:
Payments on and repurchases of long-term debt, including current portions and refinancing costs	0	0
Increase (decrease) due from-to affiliates, net	0	0
Net Cash Provided by (Used in) Financing Activities	0	0
Effect of Exchange Rates on Cash and Cash Equivalents	0	0
Net Change in Cash and Cash Equivalents	0	0
Cash and Cash Equivalents at Beginning of Period	0	0
Cash and Cash Equivalents at End of Period	0	0
Payments for (Proceeds from) Other Investing Activities		$ 0

Increase Decrease Due From Affiliates, Financing

No definition available.

Name:	lvlt_IncreaseDecreaseDueFromAffiliatesFinancing
Namespace Prefix:	lvlt_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Cash

-URI http://asc.fasb.org/extlink&oid=6506951

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Cash Equivalents

-URI http://asc.fasb.org/extlink&oid=6507016

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 1

-Article 5

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.1)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section 45

-Paragraph 1

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=28358313&loc=d3e6676-107765

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3044-108585

+ Details

Name:	us-gaap_CashAndCashEquivalentsAtCarryingValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of increase (decrease) in cash and cash equivalents. Cash and cash equivalents are the amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Includes effect from exchange rate changes.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 24

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3521-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 830

-SubTopic 230

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6450594&loc=d3e33268-110906

+ Details

Name:	us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_CondensedFinancialStatementsCaptionsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of increase (decrease) from the effect of exchange rate changes on cash and cash equivalent balances held in foreign currencies.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 830

-SubTopic 230

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6450594&loc=d3e33268-110906

+ Details

Name:	us-gaap_EffectOfExchangeRateOnCashAndCashEquivalents
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The net cash inflow or outflow during the period for the aggregate increase (decrease) associated with funds and investments that are not available for withdrawal or use (such as assets held in escrow or contractually limited as to use or disposition) and are associated with underlying transactions that are classified as investing activities.

+ References

No definition available.

+ Details

Name:	us-gaap_IncreaseDecreaseInRestrictedCashAndInvestments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of cash inflow (outflow) from financing activities, including discontinued operations. Financing activity cash flows include obtaining resources from owners and providing them with a return on, and a return of, their investment; borrowing money and repaying amounts borrowed, or settling the obligation; and obtaining and paying for other resources obtained from creditors on long-term credit.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 24

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3521-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 26

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3574-108585

+ Details

Name:	us-gaap_NetCashProvidedByUsedInFinancingActivities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of cash inflow (outflow) from investing activities, including discontinued operations. Investing activity cash flows include making and collecting loans and acquiring and disposing of debt or equity instruments and property, plant, and equipment and other productive assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 24

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3521-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 26

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3574-108585

+ Details

Name:	us-gaap_NetCashProvidedByUsedInInvestingActivities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of cash inflow (outflow) from operating activities, including discontinued operations. Operating activity cash flows include transactions, adjustments, and changes in value not defined as investing or financing activities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 24

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3521-108585

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 25

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3536-108585

+ Details

Name:	us-gaap_NetCashProvidedByUsedInOperatingActivities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration

- Definition

The net cash outflow or inflow from other investing activities. This element is used when there is not a more specific and appropriate element in the taxonomy.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Investing Activities

-URI http://asc.fasb.org/extlink&oid=6516133

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 8

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3095-108585

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 9

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3098-108585

+ Details

Name:	us-gaap_PaymentsForProceedsFromOtherInvestingActivities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The cash outflow for purchases of and capital improvements on property, plant and equipment (capital expenditures), software, and other intangible assets.

+ References

+ Details

Name:	us-gaap_PaymentsToAcquireProductiveAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The cash outflow associated with security instruments that either represent a creditor or an ownership relationship with the holder of the investment security with a maturity of beyond one year or normal operating cycle, if longer. Includes repayments of (a) debt, (b) capital lease obligations, (c) mandatory redeemable capital securities, and (d) any combination of (a), (b), or (c).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Financing Activities

-URI http://asc.fasb.org/extlink&oid=6513228

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 15

-Subparagraph (a),(b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3291-108585

+ Details

Name:	us-gaap_RepaymentsOfLongTermDebtAndCapitalSecurities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration