Fair Value of Financial Instruments - Liabilities, Additional Information (Details) (USD $) In Millions, unless otherwise specified								9 Months Ended
	Sep. 30, 2013 Term Loans	Sep. 30, 2013 11.875% Senior Notes due 2019	Dec. 31, 2012 11.875% Senior Notes due 2019	Sep. 30, 2013 8.875% Senior Notes due 2019	Dec. 31, 2012 8.875% Senior Notes due 2019	Sep. 30, 2013 6.5% Convertible Senior Notes due 2016	Dec. 31, 2012 6.5% Convertible Senior Notes due 2016	Sep. 30, 2013 Not actively traded convertible notes	Sep. 30, 2013 7.0% Convertible Senior Notes due 2015	Dec. 31, 2012 7.0% Convertible Senior Notes due 2015	Sep. 30, 2013 7.0% Convertible Senior Notes due 2015 Series B	Dec. 31, 2012 7.0% Convertible Senior Notes due 2015 Series B	Sep. 30, 2013 15.0% Convertible Senior Notes due 2013	Dec. 31, 2012 15.0% Convertible Senior Notes due 2013	Sep. 30, 2013 Estimate of Fair Value, Fair Value Disclosure Term Loans	Dec. 31, 2012 Estimate of Fair Value, Fair Value Disclosure Term Loans	Sep. 30, 2013 Estimate of Fair Value, Fair Value Disclosure Actively traded convertible notes	Dec. 31, 2012 Estimate of Fair Value, Fair Value Disclosure Actively traded convertible notes	Sep. 30, 2013 Estimate of Fair Value, Fair Value Disclosure Not actively traded convertible notes	Dec. 31, 2012 Estimate of Fair Value, Fair Value Disclosure Not actively traded convertible notes	Sep. 30, 2013 Fair Value, Measurements, Recurring Estimate of Fair Value, Fair Value Disclosure Senior Notes	Dec. 31, 2012 Fair Value, Measurements, Recurring Estimate of Fair Value, Fair Value Disclosure Senior Notes
Liabilities measured on a recurring basis
Term Loans															$ 2,600	$ 2,600
Collateral for debt, Equity interest in Level 3 Financing, Inc's Canadian subsidiary (as a percent)	65.00%
Senior Notes																					5,600	5,700
Convertible Notes																	$ 304	$ 286	$ 581	$ 748
Stated interest rate (as a percent)		11.875%	11.875%	8.875%	8.875%	6.50%	6.50%		7.00%	7.00%	7.00%	7.00%	15.00%	15.00%
Security coupon rates used for valuation, lowest interest rate								7.00%
Security coupon rates used for valuation, highest interest rate								15.00%