Condensed Consolidating Financial Information - Statements of Cash Flows (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Condensed Consolidating Financial Information
Net Cash Provided by (Used in) Operating Activities	$ 141	$ 7
Cash Flows from Investing Activities:
Capital expenditures	(163)	(169)
Decrease in restricted cash and securities, net	1	3
Net Cash Provided by (Used in) Investing Activities	(162)	(166)
Cash Flows from Financing Activities:
Long-term debt borrowings, net of issuance costs	0	0
Payments on and repurchases of long-term debt, including current portions and refinancing costs	(3)	(186)
Increase (decrease) due from-to affiliates, net	0	0
Net Cash Provided by (Used in) Financing Activities	(3)	(186)
Effect of Exchange Rates on Cash and Cash Equivalents	0	(24)
Net Change in Cash and Cash Equivalents	(24)	(369)
Cash and Cash Equivalents at Beginning of Period	631	979
Cash and Cash Equivalents at End of Period	607	610
Level 3 Communications, Inc.
Condensed Consolidating Financial Information
Net Cash Provided by (Used in) Operating Activities	(16)	(30)
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:
Long-term debt borrowings, net of issuance costs	0	0
Payments on and repurchases of long-term debt, including current portions and refinancing costs	0	(172)
Increase (decrease) due from-to affiliates, net	16	1
Net Cash Provided by (Used in) Financing Activities	16	(171)
Effect of Exchange Rates on Cash and Cash Equivalents	0	0
Net Change in Cash and Cash Equivalents	0	(201)
Cash and Cash Equivalents at Beginning of Period	8	253
Cash and Cash Equivalents at End of Period	8	52
Level 3 Financing, Inc.
Condensed Consolidating Financial Information
Net Cash Provided by (Used in) Operating Activities	(125)	(169)
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:
Long-term debt borrowings, net of issuance costs	0	0
Payments on and repurchases of long-term debt, including current portions and refinancing costs	0	(2)
Increase (decrease) due from-to affiliates, net	125	171
Net Cash Provided by (Used in) Financing Activities	125	169
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
Level 3 Communications, LLC
Condensed Consolidating Financial Information
Net Cash Provided by (Used in) Operating Activities	183	(15)
Cash Flows from Investing Activities:
Capital expenditures	(74)	(74)
Decrease in restricted cash and securities, net	0	0
Net Cash Provided by (Used in) Investing Activities	(74)	(74)
Cash Flows from Financing Activities:
Long-term debt borrowings, net of issuance costs	0	0
Payments on and repurchases of long-term debt, including current portions and refinancing costs	0	(4)
Increase (decrease) due from-to affiliates, net	(100)	35
Net Cash Provided by (Used in) Financing Activities	(100)	31
Effect of Exchange Rates on Cash and Cash Equivalents	0	0
Net Change in Cash and Cash Equivalents	9	(58)
Cash and Cash Equivalents at Beginning of Period	347	386
Cash and Cash Equivalents at End of Period	356	328
Other Non-Guarantor Subsidiaries
Condensed Consolidating Financial Information
Net Cash Provided by (Used in) Operating Activities	99	221
Cash Flows from Investing Activities:
Capital expenditures	(89)	(95)
Decrease in restricted cash and securities, net	1	3
Net Cash Provided by (Used in) Investing Activities	(88)	(92)
Cash Flows from Financing Activities:
Long-term debt borrowings, net of issuance costs	0	0
Payments on and repurchases of long-term debt, including current portions and refinancing costs	(3)	(8)
Increase (decrease) due from-to affiliates, net	(41)	(207)
Net Cash Provided by (Used in) Financing Activities	(44)	(215)
Effect of Exchange Rates on Cash and Cash Equivalents	0	(24)
Net Change in Cash and Cash Equivalents	(33)	(110)
Cash and Cash Equivalents at Beginning of Period	270	335
Cash and Cash Equivalents at End of Period	237	225
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:
Long-term debt borrowings, net of issuance costs	0	0
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