Condensed Consolidating Financial Information - Statements of Cash Flows (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Condensed Consolidating Financial Information
Net Cash Provided by (Used in) Operating Activities of Continuing Operations	$ 388	$ 339	$ 346
Cash Flows from Investing Activities:
Capital expenditures	(494)	(435)	(308)
(Increase) Decrease in restricted cash and securities, net	(54)	3	5
Proceeds from the sale of property, plant and equipment and other assets	4	4	1
Net Cash Used in Investing Activities in Investing Activities of Continuing Operations	(398)	(428)	(302)
Cash Flows from Financing Activities:
Long-term debt borrowings, net of issuance costs	1,878.0	808.0	543.0
Payments on and repurchases of long-term debt, including current portions and refinancing costs	(1,617)	(930)	(527)
Increase (decrease) due from affiliates, net	0	0	0
Net Cash Provided by (Used in) Financing Activities of Continuing Operations	261	(122)	16
Net Cash Provided by (Used in) Discontinued Operations	51	(1)	6
Effect of Exchange Rates on Cash and Cash Equivalents	0	(8)	2
Net Change in Cash and Cash Equivalents	302	(220)	68
Cash and Cash Equivalents at Beginning of Year	616	836	768
Cash and Cash Equivalents at End of Year	918	616	836
Level 3 Communications, Inc.
Condensed Consolidating Financial Information
Net Cash Provided by (Used in) Operating Activities of Continuing Operations	(176)	(156)	(142)
Cash Flows from Investing Activities:
Capital expenditures	0	0	0
(Increase) Decrease in restricted cash and securities, net	0	0	0
Proceeds from the sale of property, plant and equipment and other assets	0	0	0
Net Cash Used in Investing Activities in Investing Activities of Continuing Operations	0	0	0
Cash Flows from Financing Activities:
Long-term debt borrowings, net of issuance costs	292.0	195.0	269.0
Payments on and repurchases of long-term debt, including current portions and refinancing costs	(521)	(328)	(518)
Increase (decrease) due from affiliates, net	234	226	560
Net Cash Provided by (Used in) Financing Activities of Continuing Operations	5	93	311
Net Cash Provided by (Used in) Discontinued Operations	0	0	0
Effect of Exchange Rates on Cash and Cash Equivalents	0	0	0
Net Change in Cash and Cash Equivalents	(171)	(63)	169
Cash and Cash Equivalents at Beginning of Year	173	236	67
Cash and Cash Equivalents at End of Year	2	173	236
Level 3 Financing, Inc.
Condensed Consolidating Financial Information
Net Cash Provided by (Used in) Operating Activities of Continuing Operations	(428)	(362)	(369)
Cash Flows from Investing Activities:
Capital expenditures	0	0	0
(Increase) Decrease in restricted cash and securities, net	0	0	0
Proceeds from the sale of property, plant and equipment and other assets	0	0	0
Net Cash Used in Investing Activities in Investing Activities of Continuing Operations	0	0	0
Cash Flows from Financing Activities:
Long-term debt borrowings, net of issuance costs	1,586.0	613.0	274.0
Payments on and repurchases of long-term debt, including current portions and refinancing costs	(755)	(599)	(6)
Increase (decrease) due from affiliates, net	(404)	347	99
Net Cash Provided by (Used in) Financing Activities of Continuing Operations	427	361	367
Net Cash Provided by (Used in) Discontinued Operations	0	0	0
Effect of Exchange Rates on Cash and Cash Equivalents	0	0	0
Net Change in Cash and Cash Equivalents	(1)	(1)	(2)
Cash and Cash Equivalents at Beginning of Year	7	8	10
Cash and Cash Equivalents at End of Year	6	7	8
Level 3 Communications, LLC
Condensed Consolidating Financial Information
Net Cash Provided by (Used in) Operating Activities of Continuing Operations	293	76	(154)
Cash Flows from Investing Activities:
Capital expenditures	(197)	(161)	(121)
(Increase) Decrease in restricted cash and securities, net	3	3	2
Proceeds from the sale of property, plant and equipment and other assets	1	2	0
Net Cash Used in Investing Activities in Investing Activities of Continuing Operations	(193)	(156)	(119)
Cash Flows from Financing Activities:
Long-term debt borrowings, net of issuance costs	0	0	0
Payments on and repurchases of long-term debt, including current portions and refinancing costs	0	(1)	(1)
Increase (decrease) due from affiliates, net	168	0	150
Net Cash Provided by (Used in) Financing Activities of Continuing Operations	168	(1)	149
Net Cash Provided by (Used in) Discontinued Operations	0	0	0
Effect of Exchange Rates on Cash and Cash Equivalents	0	0	0
Net Change in Cash and Cash Equivalents	268	(81)	(124)
Cash and Cash Equivalents at Beginning of Year	350	431	555
Cash and Cash Equivalents at End of Year	618	350	431
Broadwing
Condensed Consolidating Financial Information
Net Cash Provided by (Used in) Operating Activities of Continuing Operations			0
Cash Flows from Investing Activities:
Capital expenditures			0
(Increase) Decrease in restricted cash and securities, net			0
Proceeds from the sale of property, plant and equipment and other assets			0
Net Cash Used in Investing Activities in Investing Activities of Continuing Operations			0
Cash Flows from Financing Activities:
Long-term debt borrowings, net of issuance costs			0
Payments on and repurchases of long-term debt, including current portions and refinancing costs			0
Increase (decrease) due from affiliates, net			0
Net Cash Provided by (Used in) Financing Activities of Continuing Operations			0
Net Cash Provided by (Used in) Discontinued Operations			0
Effect of Exchange Rates on Cash and Cash Equivalents			0
Net Change in Cash and Cash Equivalents			0
Cash and Cash Equivalents at Beginning of Year			0
Cash and Cash Equivalents at End of Year			0
Other Non-Guarantor Subsidiaries
Condensed Consolidating Financial Information
Net Cash Provided by (Used in) Operating Activities of Continuing Operations	699	781	1,011
Cash Flows from Investing Activities:
Capital expenditures	(297)	(274)	(187)
(Increase) Decrease in restricted cash and securities, net	(57)	0	3
Proceeds from the sale of property, plant and equipment and other assets	3	2	1
Net Cash Used in Investing Activities in Investing Activities of Continuing Operations	(205)	(272)	(183)
Cash Flows from Financing Activities:
Long-term debt borrowings, net of issuance costs	0	0	0
Payments on and repurchases of long-term debt, including current portions and refinancing costs	(341)	(2)	(2)
Increase (decrease) due from affiliates, net	2	(573)	(809)
Net Cash Provided by (Used in) Financing Activities of Continuing Operations	(339)	(575)	(811)
Net Cash Provided by (Used in) Discontinued Operations	51	(1)	6
Effect of Exchange Rates on Cash and Cash Equivalents	0	(8)	2
Net Change in Cash and Cash Equivalents	206	(75)	25
Cash and Cash Equivalents at Beginning of Year	86	161	136
Cash and Cash Equivalents at End of Year	292	86	161
Eliminations
Condensed Consolidating Financial Information
Net Cash Provided by (Used in) Operating Activities of Continuing Operations	0	0	0
Cash Flows from Investing Activities:
Capital expenditures	0	0	0
(Increase) Decrease in restricted cash and securities, net	0	0	0
Proceeds from the sale of property, plant and equipment and other assets	0	0	0
Net Cash Used in Investing Activities in Investing Activities of Continuing Operations	0	0	0
Cash Flows from Financing Activities:
Long-term debt borrowings, net of issuance costs	0	0	0
Payments on and repurchases of long-term debt, including current portions and refinancing costs	0	0	0
Increase (decrease) due from affiliates, net	0	0	0
Net Cash Provided by (Used in) Financing Activities of Continuing Operations	0	0	0
Net Cash Provided by (Used in) Discontinued Operations	0	0	0
Effect of Exchange Rates on Cash and Cash Equivalents	0	0	0
Net Change in Cash and Cash Equivalents	0	0	0
Cash and Cash Equivalents at Beginning of Year	0	0	0
Cash and Cash Equivalents at End of Year	$ 0	$ 0	$ 0