Condensed Consolidating Financial Information - Statements of Cash Flows (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Condensed Consolidating Financial Information
Net Cash Provided by (Used in) Operating Activities of Continuing Operations	$ 713	$ 578	$ 388
Cash Flows from Investing Activities:
Capital expenditures	(760)	(743)	(494)
(Increase) Decrease in restricted cash and securities, net	13	20	(54)
Proceeds from the sale of property, plant and equipment and other assets			4
Investment in Global Crossing, net of cash acquired	0	0	146
Payments for other investing activities	2	(2)	4
Net Cash Used in Investing Activities in Investing Activities of Continuing Operations	(745)	(725)	(398)
Cash Flows from Financing Activities:
Long-term debt borrowings, net of issuance costs	1,502.0	4,504.0	1,878.0
Payments on and repurchases of long-term debt, including current portions and refinancing costs	(1,796)	(4,302)	(1,617)
Proceeds from Stock Options Exercised	0	5	0
Increase (decrease) due from affiliates, net	0	0	0
Net Cash Provided by (Used in) Financing Activities of Continuing Operations	(294)	207	261
Net Cash Provided by (Used in) Discontinued Operations	0	0	51
Effect of Exchange Rates on Cash and Cash Equivalents	(22)	1	0
Net Change in Cash and Cash Equivalents	(348)	61	302
Cash and Cash Equivalents at Beginning of Year	979	918	616
Cash and Cash Equivalents at End of Year	631	979	918
Level 3 Communications, Inc.
Condensed Consolidating Financial Information
Net Cash Provided by (Used in) Operating Activities of Continuing Operations	(169)	(165)	(176)
Cash Flows from Investing Activities:
Capital expenditures	0	0	0
(Increase) Decrease in restricted cash and securities, net	9	6	0
Proceeds from the sale of property, plant and equipment and other assets			0
Investment in Global Crossing, net of cash acquired			0
Payments for other investing activities	0	0
Net Cash Used in Investing Activities in Investing Activities of Continuing Operations	9	6	0
Cash Flows from Financing Activities:
Long-term debt borrowings, net of issuance costs	0	293.0	292.0
Payments on and repurchases of long-term debt, including current portions and refinancing costs	(173)	0	(521)
Proceeds from Stock Options Exercised		5
Increase (decrease) due from affiliates, net	88	112	234
Net Cash Provided by (Used in) Financing Activities of Continuing Operations	(85)	410	5
Net Cash Provided by (Used in) Discontinued Operations			0
Effect of Exchange Rates on Cash and Cash Equivalents	0	0	0
Net Change in Cash and Cash Equivalents	(245)	251	(171)
Cash and Cash Equivalents at Beginning of Year	253	2	173
Cash and Cash Equivalents at End of Year	8	253	2
Level 3 Financing, Inc.
Condensed Consolidating Financial Information
Net Cash Provided by (Used in) Operating Activities of Continuing Operations	(557)	(520)	(428)
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
Investment in Global Crossing, net of cash acquired			0
Payments for other investing activities	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	1,502.0	4,211.0	1,586.0
Payments on and repurchases of long-term debt, including current portions and refinancing costs	(1,586)	(4,161)	(755)
Proceeds from Stock Options Exercised		0
Increase (decrease) due from affiliates, net	642	469	(404)
Net Cash Provided by (Used in) Financing Activities of Continuing Operations	558	519	427
Net Cash Provided by (Used in) Discontinued Operations			0
Effect of Exchange Rates on Cash and Cash Equivalents	0	0	0
Net Change in Cash and Cash Equivalents	1	(1)	(1)
Cash and Cash Equivalents at Beginning of Year	5	6	7
Cash and Cash Equivalents at End of Year	6	5	6
Level 3 Communications, LLC
Condensed Consolidating Financial Information
Net Cash Provided by (Used in) Operating Activities of Continuing Operations	710	140	293
Cash Flows from Investing Activities:
Capital expenditures	(312)	(276)	(197)
(Increase) Decrease in restricted cash and securities, net	(1)	2	3
Proceeds from the sale of property, plant and equipment and other assets			1
Investment in Global Crossing, net of cash acquired			0
Payments for other investing activities	1	0
Net Cash Used in Investing Activities in Investing Activities of Continuing Operations	(312)	(274)	(193)
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	(4)	0	0
Proceeds from Stock Options Exercised		0
Increase (decrease) due from affiliates, net	(433)	(98)	168
Net Cash Provided by (Used in) Financing Activities of Continuing Operations	(437)	(98)	168
Net Cash Provided by (Used in) Discontinued Operations			0
Effect of Exchange Rates on Cash and Cash Equivalents	0	0	0
Net Change in Cash and Cash Equivalents	(39)	(232)	268
Cash and Cash Equivalents at Beginning of Year	386	618	350
Cash and Cash Equivalents at End of Year	347	386	618
Other Non-Guarantor Subsidiaries
Condensed Consolidating Financial Information
Net Cash Provided by (Used in) Operating Activities of Continuing Operations	729	1,123	699
Cash Flows from Investing Activities:
Capital expenditures	(448)	(467)	(297)
(Increase) Decrease in restricted cash and securities, net	5	12	(57)
Proceeds from the sale of property, plant and equipment and other assets			3
Investment in Global Crossing, net of cash acquired			(146)
Payments for other investing activities	1	(2)
Net Cash Used in Investing Activities in Investing Activities of Continuing Operations	(442)	(457)	(205)
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	(33)	(141)	(341)
Proceeds from Stock Options Exercised		0
Increase (decrease) due from affiliates, net	(297)	(483)	2
Net Cash Provided by (Used in) Financing Activities of Continuing Operations	(330)	(624)	(339)
Net Cash Provided by (Used in) Discontinued Operations			51
Effect of Exchange Rates on Cash and Cash Equivalents	(22)	1	0
Net Change in Cash and Cash Equivalents	(65)	43	206
Cash and Cash Equivalents at Beginning of Year	335	292	86
Cash and Cash Equivalents at End of Year	270	335	292
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
Investment in Global Crossing, net of cash acquired			0
Payments for other investing activities	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
Proceeds from Stock Options Exercised		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
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