Subsequent Events (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2013 Convertible Senior Notes due 2013 (15.0%)	Mar. 31, 2012 Convertible Senior Notes due 2013 (15.0%)	Dec. 31, 2011 Convertible Senior Notes due 2013 (15.0%)	Dec. 31, 2013 Level 3 Communications, Inc.	Dec. 31, 2012 Level 3 Communications, Inc.	Dec. 31, 2011 Level 3 Communications, Inc.	Dec. 31, 2010 Level 3 Communications, Inc.	Dec. 31, 2013 Level 3 Communications, Inc. Convertible Senior Notes due 2013 (15.0%)
Subsequent Events
Debt instrument, stated interest rate (as a percent)					15.00%	15.00%	15.00%					15.00%
Cash and cash equivalents	$ 631	$ 979	$ 918	$ 616				$ 8	$ 253	$ 2	$ 173
Other, net	$ (4)	$ (58)	$ (23)