Condensed Consolidating Financial Information - Statements of Operations (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Condensed Consolidating Financial Information
Revenue	$ 1,586	$ 914
Costs and Expenses:
Cost of Revenue	657	357
Depreciation and Amortization	187	203
Selling, General and Administrative	622	357
Restructuring Charges	4	0
Total Costs and Expenses	1,470	917
Operating Income (Loss)	116	(3)
Other Income (Expense):
Interest Income	1	0
Interest expense	(189)	(157)
Interest income (expense) affiliates, net	0	0
Equity in net earnings (losses) of subsidiaries	0	0
Other income (expense), net	(52)	(17)
Nonoperating Income (Expense)	(240)	(174)
Loss Before Income Taxes	(124)	(177)
Income Tax Expense	(14)	(27)
Loss from Continuing Operations	(138)	(204)
Income (Loss) from Discontinued Operations, Net	0	(1)
Net Loss	(138)	(205)
Other Comprehensive Income (Loss), Net of Income Taxes	42	51
Comprehensive Loss	(96)	(154)
Level 3 Communications, Inc.
Condensed Consolidating Financial Information
Revenue	0	0
Costs and Expenses:
Cost of Revenue	0	0
Depreciation and Amortization	0	0
Selling, General and Administrative	1	0
Restructuring Charges	0	0
Total Costs and Expenses	1	0
Operating Income (Loss)	(1)	0
Other Income (Expense):
Interest Income	0	0
Interest expense	(42)	(57)
Interest income (expense) affiliates, net	245	210
Equity in net earnings (losses) of subsidiaries	(301)	(337)
Other income (expense), net	(39)	(21)
Nonoperating Income (Expense)	(137)	(205)
Loss Before Income Taxes	(138)	(205)
Income Tax Expense	0	0
Loss from Continuing Operations		(205)
Income (Loss) from Discontinued Operations, Net		0
Net Loss	(138)	(205)
Other Comprehensive Income (Loss), Net of Income Taxes	42	51
Comprehensive Loss	(96)	(154)
Level 3 Financing, Inc.
Condensed Consolidating Financial Information
Revenue	0	0
Costs and Expenses:
Cost of Revenue	0	0
Depreciation and Amortization	0	0
Selling, General and Administrative	0	0
Restructuring Charges	0	0
Total Costs and Expenses	0	0
Operating Income (Loss)	0	0
Other Income (Expense):
Interest Income	0	0
Interest expense	(139)	(98)
Interest income (expense) affiliates, net	399	361
Equity in net earnings (losses) of subsidiaries	(539)	(600)
Other income (expense), net	(22)	0
Nonoperating Income (Expense)	(301)	(337)
Loss Before Income Taxes	(301)	(337)
Income Tax Expense	0	0
Loss from Continuing Operations		(337)
Income (Loss) from Discontinued Operations, Net		0
Net Loss	(301)	(337)
Other Comprehensive Income (Loss), Net of Income Taxes	42	51
Comprehensive Loss	(259)	(286)
Level 3 Communications, LLC
Condensed Consolidating Financial Information
Revenue	626	560
Costs and Expenses:
Cost of Revenue	236	212
Depreciation and Amortization	67	103
Selling, General and Administrative	401	307
Restructuring Charges	0	0
Total Costs and Expenses	704	622
Operating Income (Loss)	(78)	(62)
Other Income (Expense):
Interest Income	1	0
Interest expense	0	(1)
Interest income (expense) affiliates, net	(559)	(516)
Equity in net earnings (losses) of subsidiaries	36	42
Other income (expense), net	1	3
Nonoperating Income (Expense)	(521)	(472)
Loss Before Income Taxes	(599)	(534)
Income Tax Expense	(1)	0
Loss from Continuing Operations		(534)
Income (Loss) from Discontinued Operations, Net		0
Net Loss	(600)	(534)
Other Comprehensive Income (Loss), Net of Income Taxes	0	0
Comprehensive Loss	(600)	(534)
Other Non-Guarantor Subsidiaries
Condensed Consolidating Financial Information
Revenue	1,023	406
Costs and Expenses:
Cost of Revenue	481	194
Depreciation and Amortization	120	100
Selling, General and Administrative	223	53
Restructuring Charges	4	0
Total Costs and Expenses	828	347
Operating Income (Loss)	195	59
Other Income (Expense):
Interest Income	0	0
Interest expense	(8)	(1)
Interest income (expense) affiliates, net	(85)	(55)
Equity in net earnings (losses) of subsidiaries	0	0
Other income (expense), net	8	1
Nonoperating Income (Expense)	(85)	(55)
Loss Before Income Taxes	110	4
Income Tax Expense	(13)	(27)
Loss from Continuing Operations		(23)
Income (Loss) from Discontinued Operations, Net		(1)
Net Loss	97	(24)
Other Comprehensive Income (Loss), Net of Income Taxes	35	41
Comprehensive Loss	132	17
Eliminations
Condensed Consolidating Financial Information
Revenue	(63)	(52)
Costs and Expenses:
Cost of Revenue	(60)	(49)
Depreciation and Amortization	0	0
Selling, General and Administrative	(3)	(3)
Restructuring Charges	0	0
Total Costs and Expenses	(63)	(52)
Operating Income (Loss)	0	0
Other Income (Expense):
Interest Income	0	0
Interest expense	0	0
Interest income (expense) affiliates, net	0	0
Equity in net earnings (losses) of subsidiaries	804	895
Other income (expense), net	0	0
Nonoperating Income (Expense)	804	895
Loss Before Income Taxes	804	895
Income Tax Expense	0	0
Loss from Continuing Operations		895
Income (Loss) from Discontinued Operations, Net		0
Net Loss	804	895
Other Comprehensive Income (Loss), Net of Income Taxes	(77)	(92)
Comprehensive Loss	$ 727	$ 803