Condensed Consolidating Financial Information - Statements of Cash Flows (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Condensed Consolidating Financial Information
Net Cash Provided by (Used in) Operating Activities of Continuing Operations	$ (75)	$ 1
Cash Flows from Investing Activities:
Capital expenditures	(138)	(115)
(Increase) Decrease in restricted cash and securities, net	1	(1)
Proceeds from the sale of property, plant and equipment and other assets	5	2
Net Cash Used in Investing Activities in Investing Activities of Continuing Operations	(132)	(114)
Cash Flows from Financing Activities:
Long-term debt borrowings, net of issuance costs	880	772
Payments on and repurchases of long-term debt, including current portions and refinancing costs	(847)	(198)
Proceeds from Stock Options Exercised	1	0
Increase (decrease) due from affiliates, net	0	0
Net Cash Provided by (Used in) Financing Activities of Continuing Operations	34	574
Net Cash Provided by (Used in) Discontinued Operations	0	(1)
Effect of Exchange Rates on Cash and Cash Equivalents	3	3
Net Change in Cash and Cash Equivalents	(170)	463
Cash and Cash Equivalents at Beginning of Year	918	616
Cash and Cash Equivalents at End of Year	748	1,079
Level 3 Communications, Inc.
Condensed Consolidating Financial Information
Net Cash Provided by (Used in) Operating Activities of Continuing Operations	(36)	(56)
Cash Flows from Investing Activities:
Capital expenditures	0	0
(Increase) Decrease in restricted cash and securities, net	0	0
Proceeds from the sale of property, plant and equipment and other assets	0	0
Net Cash Used in Investing Activities in Investing Activities of Continuing Operations	0	0
Cash Flows from Financing Activities:
Long-term debt borrowings, net of issuance costs	0	292
Payments on and repurchases of long-term debt, including current portions and refinancing costs	0	(197)
Proceeds from Stock Options Exercised	1
Increase (decrease) due from affiliates, net	34	3
Net Cash Provided by (Used in) Financing Activities of Continuing Operations	35	98
Net Cash Provided by (Used in) Discontinued Operations		0
Effect of Exchange Rates on Cash and Cash Equivalents	0	0
Net Change in Cash and Cash Equivalents	(1)	42
Cash and Cash Equivalents at Beginning of Year	2	173
Cash and Cash Equivalents at End of Year	1	215
Level 3 Financing, Inc.
Condensed Consolidating Financial Information
Net Cash Provided by (Used in) Operating Activities of Continuing Operations	(184)	(77)
Cash Flows from Investing Activities:
Capital expenditures	0	0
(Increase) Decrease in restricted cash and securities, net	0	0
Proceeds from the sale of property, plant and equipment and other assets	0	0
Net Cash Used in Investing Activities in Investing Activities of Continuing Operations	0	0
Cash Flows from Financing Activities:
Long-term debt borrowings, net of issuance costs	880	480
Payments on and repurchases of long-term debt, including current portions and refinancing costs	(825)	0
Proceeds from Stock Options Exercised	0
Increase (decrease) due from affiliates, net	129	(403)
Net Cash Provided by (Used in) Financing Activities of Continuing Operations	184	77
Net Cash Provided by (Used in) Discontinued Operations		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 Year	6	7
Cash and Cash Equivalents at End of Year	6	7
Level 3 Communications, LLC
Condensed Consolidating Financial Information
Net Cash Provided by (Used in) Operating Activities of Continuing Operations	(74)	0
Cash Flows from Investing Activities:
Capital expenditures	(61)	(44)
(Increase) Decrease in restricted cash and securities, net	1	0
Proceeds from the sale of property, plant and equipment and other assets	0	1
Net Cash Used in Investing Activities in Investing Activities of Continuing Operations	(60)	(43)
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
Proceeds from Stock Options Exercised	0
Increase (decrease) due from affiliates, net	(63)	472
Net Cash Provided by (Used in) Financing Activities of Continuing Operations	(63)	472
Net Cash Provided by (Used in) Discontinued Operations		0
Effect of Exchange Rates on Cash and Cash Equivalents	0	0
Net Change in Cash and Cash Equivalents	(197)	429
Cash and Cash Equivalents at Beginning of Year	618	350
Cash and Cash Equivalents at End of Year	421	779
Other Non-Guarantor Subsidiaries
Condensed Consolidating Financial Information
Net Cash Provided by (Used in) Operating Activities of Continuing Operations	219	134
Cash Flows from Investing Activities:
Capital expenditures	(77)	(71)
(Increase) Decrease in restricted cash and securities, net	0	(1)
Proceeds from the sale of property, plant and equipment and other assets	5	1
Net Cash Used in Investing Activities in Investing Activities of Continuing Operations	(72)	(71)
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	(22)	(1)
Proceeds from Stock Options Exercised	0
Increase (decrease) due from affiliates, net	(100)	(72)
Net Cash Provided by (Used in) Financing Activities of Continuing Operations	(122)	(73)
Net Cash Provided by (Used in) Discontinued Operations		(1)
Effect of Exchange Rates on Cash and Cash Equivalents	3	3
Net Change in Cash and Cash Equivalents	28	(8)
Cash and Cash Equivalents at Beginning of Year	292	86
Cash and Cash Equivalents at End of Year	320	78
Eliminations
Condensed Consolidating Financial Information
Net Cash Provided by (Used in) Operating Activities of Continuing Operations	0	0
Cash Flows from Investing Activities:
Capital expenditures	0	0
(Increase) Decrease in restricted cash and securities, net	0	0
Proceeds from the sale of property, plant and equipment and other assets	0	0
Net Cash Used in Investing Activities in Investing Activities of Continuing Operations	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
Proceeds from Stock Options Exercised	0
Increase (decrease) due from affiliates, net	0	0
Net Cash Provided by (Used in) Financing Activities of Continuing Operations	0	0
Net Cash Provided by (Used in) Discontinued Operations		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 Year	0	0
Cash and Cash Equivalents at End of Year	$ 0	$ 0