Condensed Consolidating Financial Information - Balance Sheets (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011	Mar. 31, 2011	Dec. 31, 2010
Current Assets:
Cash and cash equivalents	$ 748	$ 918	$ 1,079	$ 616
Restricted cash and securities	8	10
Receivables, less allowances for doubtful accounts	683	648
Due from (to) affiliates	0	0
Other	164	131
Total Current Assets	1,603	1,707
Property, Plant and Equipment, net of accumulated depreciation	8,164	8,136
Restricted Cash and Securities	52	51
Goodwill and Other Intangibles Assets, net	2,830	2,899
Investment in Subsidiaries	0	0
Other Assets, net	425	395
Total Assets	13,074	13,188
Current Liabilities:
Accounts payable	724	747
Current portion of long-term debt	227	65
Accrued payroll and employee benefits	115	209
Accrued interest	165	216
Current portion of deferred revenue	259	264
Other	145	157
Total Current Liabilities	1,635	1,658
Long-Term Debt, less current portion	8,199	8,385
Deferred Revenue, less current portion	884	885
Other Liabilities	1,047	1,067
Stockholders' Equity (Deficit)	1,309	1,193
Total Liabilities and Stockholders' Equity (Deficit)	13,074	13,188
Level 3 Communications, Inc.
Current Assets:
Cash and cash equivalents	1	2	215	173
Restricted cash and securities	0	0
Receivables, less allowances for doubtful accounts	0	0
Due from (to) affiliates	13,748	13,472
Other	3	3
Total Current Assets	13,752	13,477
Property, Plant and Equipment, net of accumulated depreciation	0	0
Restricted Cash and Securities	18	18
Goodwill and Other Intangibles Assets, net	0	0
Investment in Subsidiaries	(10,972)	(10,718)
Other Assets, net	12	13
Total Assets	2,810	2,790
Current Liabilities:
Accounts payable	1	0
Current portion of long-term debt	168	0
Accrued payroll and employee benefits	0	0
Accrued interest	49	50
Current portion of deferred revenue	0	0
Other	0	0
Total Current Liabilities	218	50
Long-Term Debt, less current portion	1,269	1,533
Deferred Revenue, less current portion	0	0
Other Liabilities	14	14
Stockholders' Equity (Deficit)	1,309	1,193
Total Liabilities and Stockholders' Equity (Deficit)	2,810	2,790
Level 3 Financing, Inc.
Current Assets:
Cash and cash equivalents	6	6	7	7
Restricted cash and securities	0	0
Receivables, less allowances for doubtful accounts	0	0
Due from (to) affiliates	14,850	14,584
Other	16	16
Total Current Assets	14,872	14,606
Property, Plant and Equipment, net of accumulated depreciation	0	0
Restricted Cash and Securities	0	0
Goodwill and Other Intangibles Assets, net	0	0
Investment in Subsidiaries	(18,962)	(18,467)
Other Assets, net	119	109
Total Assets	(3,971)	(3,752)
Current Liabilities:
Accounts payable	0	0
Current portion of long-term debt	0	0
Accrued payroll and employee benefits	0	0
Accrued interest	114	165
Current portion of deferred revenue	0	0
Other	1	1
Total Current Liabilities	115	166
Long-Term Debt, less current portion	6,780	6,688
Deferred Revenue, less current portion	0	0
Other Liabilities	110	116
Stockholders' Equity (Deficit)	(10,976)	(10,722)
Total Liabilities and Stockholders' Equity (Deficit)	(3,971)	(3,752)
Level 3 Communications, LLC
Current Assets:
Cash and cash equivalents	421	618	779	350
Restricted cash and securities	1	1
Receivables, less allowances for doubtful accounts	63	59
Due from (to) affiliates	(28,382)	(28,092)
Other	66	48
Total Current Assets	(27,831)	(27,366)
Property, Plant and Equipment, net of accumulated depreciation	2,833	2,823
Restricted Cash and Securities	19	19
Goodwill and Other Intangibles Assets, net	465	481
Investment in Subsidiaries	3,300	3,412
Other Assets, net	8	6
Total Assets	(21,206)	(20,625)
Current Liabilities:
Accounts payable	22	37
Current portion of long-term debt	2	2
Accrued payroll and employee benefits	64	116
Accrued interest	0	0
Current portion of deferred revenue	109	107
Other	42	52
Total Current Liabilities	239	314
Long-Term Debt, less current portion	21	22
Deferred Revenue, less current portion	616	612
Other Liabilities	146	146
Stockholders' Equity (Deficit)	(22,228)	(21,719)
Total Liabilities and Stockholders' Equity (Deficit)	(21,206)	(20,625)
Other Non-Guarantor Subsidiaries
Current Assets:
Cash and cash equivalents	320	292	78	86
Restricted cash and securities	7	9
Receivables, less allowances for doubtful accounts	620	589
Due from (to) affiliates	(216)	36
Other	79	64
Total Current Assets	810	990
Property, Plant and Equipment, net of accumulated depreciation	5,331	5,313
Restricted Cash and Securities	15	14
Goodwill and Other Intangibles Assets, net	2,365	2,418
Investment in Subsidiaries	0	0
Other Assets, net	286	267
Total Assets	8,807	9,002
Current Liabilities:
Accounts payable	701	710
Current portion of long-term debt	57	63
Accrued payroll and employee benefits	51	93
Accrued interest	2	1
Current portion of deferred revenue	150	157
Other	102	104
Total Current Liabilities	1,063	1,128
Long-Term Debt, less current portion	129	142
Deferred Revenue, less current portion	268	273
Other Liabilities	777	791
Stockholders' Equity (Deficit)	6,570	6,668
Total Liabilities and Stockholders' Equity (Deficit)	8,807	9,002
Eliminations
Current Assets:
Cash and cash equivalents	0	0	0	0
Restricted cash and securities	0	0
Receivables, less allowances for doubtful accounts	0	0
Due from (to) affiliates	0	0
Other	0	0
Total Current Assets	0	0
Property, Plant and Equipment, net of accumulated depreciation	0	0
Restricted Cash and Securities	0	0
Goodwill and Other Intangibles Assets, net	0	0
Investment in Subsidiaries	26,634	25,773
Other Assets, net	0	0
Total Assets	26,634	25,773
Current Liabilities:
Accounts payable	0	0
Current portion of long-term debt	0	0
Accrued payroll and employee benefits	0	0
Accrued interest	0	0
Current portion of deferred revenue	0	0
Other	0	0
Total Current Liabilities	0	0
Long-Term Debt, less current portion	0	0
Deferred Revenue, less current portion	0	0
Other Liabilities	0	0
Stockholders' Equity (Deficit)	26,634	25,773
Total Liabilities and Stockholders' Equity (Deficit)	$ 26,634	$ 25,773