Condensed Consolidating Financial Information - Statement of Operations (Details) (USD $) In Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Condensed Consolidating Financial Information
Revenue	$ 947	$ 912	$ 2,808	$ 2,730
Costs and Expenses:
Cost of Revenue	360	368	1,098	1,125
Depreciation and Amortization	204	215	615	663
Selling, General and Administrative	375	345	1,089	1,026
Restructuring Charges	0	1	0	2
Total Costs and Expenses	939	929	2,802	2,816
Operating (Loss) Income	8	(17)	6	(86)
Other Income (Expense):
Interest expense	(178)	(144)	(495)	(438)
Interest income (expense) affiliates, net	0	0	0	0
Equity in net earnings (losses) of subsidiaries	0	0	0	0
Other, net	(31)	(1)	(68)	(44)
Total Other (Expense) Income	(209)	(145)	(563)	(482)
(Loss) Income Before Income Taxes	(201)	(162)	(557)	(568)
Income Tax Expense	(6)	(1)	(36)	(2)
Net (Loss) Income	(207)	(163)	(593)	(570)
Level 3 Communications, Inc.
Condensed Consolidating Financial Information
Revenue	0	0	0	0
Costs and Expenses:
Cost of Revenue	0	0	0	0
Depreciation and Amortization	0	0	0	0
Selling, General and Administrative	0	1	1	2
Restructuring Charges		0		0
Total Costs and Expenses	0	1	1	2
Operating (Loss) Income	0	(1)	(1)	(2)
Other Income (Expense):
Interest expense	(51)	(47)	(163)	(148)
Interest income (expense) affiliates, net	212	199	633	597
Equity in net earnings (losses) of subsidiaries	(338)	(314)	(1,011)	(1,023)
Other, net	(30)	0	(51)	6
Total Other (Expense) Income	(207)	(162)	(592)	(568)
(Loss) Income Before Income Taxes	(207)	(163)	(593)	(570)
Income Tax Expense	0	0	0	0
Net (Loss) Income	(207)	(163)	(593)	(570)
Level 3 Financing, Inc.
Condensed Consolidating Financial Information
Revenue	0	0	0	0
Costs and Expenses:
Cost of Revenue	0	0	0	0
Depreciation and Amortization	0	0	0	0
Selling, General and Administrative	0	0	0	0
Restructuring Charges		0		0
Total Costs and Expenses	0	0	0	0
Operating (Loss) Income	0	0	0	0
Other Income (Expense):
Interest expense	(99)	(94)	(296)	(282)
Interest income (expense) affiliates, net	350	325	1,069	974
Equity in net earnings (losses) of subsidiaries	(589)	(545)	(1,761)	(1,660)
Other, net	0	0	(23)	(55)
Total Other (Expense) Income	(338)	(314)	(1,011)	(1,023)
(Loss) Income Before Income Taxes	(338)	(314)	(1,011)	(1,023)
Income Tax Expense	0	0	0	0
Net (Loss) Income	(338)	(314)	(1,011)	(1,023)
Level 3 Communications, LLC
Condensed Consolidating Financial Information
Revenue	605	518	1,741	1,508
Costs and Expenses:
Cost of Revenue	222	207	658	603
Depreciation and Amortization	102	107	309	325
Selling, General and Administrative	328	298	941	886
Restructuring Charges		1		1
Total Costs and Expenses	652	613	1,908	1,815
Operating (Loss) Income	(47)	(95)	(167)	(307)
Other Income (Expense):
Interest expense	0	(1)	(2)	(1)
Interest income (expense) affiliates, net	(514)	(479)	(1,545)	(1,414)
Equity in net earnings (losses) of subsidiaries	29	42	107	129
Other, net	2	2	8	(4)
Total Other (Expense) Income	(483)	(436)	(1,432)	(1,290)
(Loss) Income Before Income Taxes	(530)	(531)	(1,599)	(1,597)
Income Tax Expense	(1)	(1)	(21)	(2)
Net (Loss) Income	(531)	(532)	(1,620)	(1,599)
Other Non-Guarantor Subsidiaries
Condensed Consolidating Financial Information
Revenue	399	454	1,236	1,394
Costs and Expenses:
Cost of Revenue	192	218	600	685
Depreciation and Amortization	102	108	306	338
Selling, General and Administrative	50	49	156	147
Restructuring Charges		0		1
Total Costs and Expenses	344	375	1,062	1,171
Operating (Loss) Income	55	79	174	223
Other Income (Expense):
Interest expense	(28)	(2)	(34)	(7)
Interest income (expense) affiliates, net	(48)	(45)	(157)	(157)
Equity in net earnings (losses) of subsidiaries	0	0	0	0
Other, net	(3)	(3)	(2)	9
Total Other (Expense) Income	(79)	(50)	(193)	(155)
(Loss) Income Before Income Taxes	(24)	29	(19)	68
Income Tax Expense	(5)	0	(15)	0
Net (Loss) Income	(29)	29	(34)	68
Eliminations
Condensed Consolidating Financial Information
Revenue	(57)	(60)	(169)	(172)
Costs and Expenses:
Cost of Revenue	(54)	(57)	(160)	(163)
Depreciation and Amortization	0	0	0	0
Selling, General and Administrative	(3)	(3)	(9)	(9)
Restructuring Charges		0		0
Total Costs and Expenses	(57)	(60)	(169)	(172)
Operating (Loss) Income	0	0	0	0
Other Income (Expense):
Interest expense	0	0	0	0
Interest income (expense) affiliates, net	0	0	0	0
Equity in net earnings (losses) of subsidiaries	898	817	2,665	2,554
Other, net	0	0	0	0
Total Other (Expense) Income	898	817	2,665	2,554
(Loss) Income Before Income Taxes	898	817	2,665	2,554
Income Tax Expense	0	0	0	0
Net (Loss) Income	$ 898	$ 817	$ 2,665	$ 2,554