Derivative Financial Instruments (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended		1 Months Ended
	Jun. 30, 2011	Mar. 31, 2007 Level 3 Financing, Inc.	Mar. 31, 2007 Level 3 Financing, Inc. Interest rate swap, agreement one	Mar. 31, 2007 Level 3 Financing, Inc. Interest rate swap, agreement two	Dec. 31, 2010 6.5% Convertible Senior Notes due in 2016	Sep. 30, 2010 6.5% Convertible Senior Notes due in 2016
Derivative Financial Instruments
Interest rate swaps, Number of Instruments		2
Notional amount of each interest rate swap agreements	$ 1,000	$ 1,000	$ 500	$ 500
Basis of interest payment	LIBOR		three month LIBOR	three month LIBOR
Fixed interest rate paid under agreement (as a percent)			4.93%	4.92%
Debt Instrument, Face Amount					$ 26	$ 175