Fair Value of Financial Instruments - Liabilities, Non Recurring (Details) (USD $) In Millions, unless otherwise specified		12 Months Ended												12 Months Ended
	Dec. 31, 2012 Term Loans	Dec. 31, 2012 Tranche B-II 2019 Term Loan	Dec. 31, 2012 Tranche B 2019 Term Loan	Dec. 31, 2012 Tranche B 2016 Term Loan	Dec. 31, 2011 Tranche B III Term Loan	Dec. 31, 2011 Tranche B II Term Loan	Dec. 31, 2011 Tranche A Term Loan	Dec. 31, 2012 Senior Notes	Dec. 31, 2012 Senior Notes due 2019 (11.875%)	Dec. 31, 2011 Senior Notes due 2019 (11.875%)	Dec. 31, 2012 Senior Notes due 2019 (8.875%)	Dec. 31, 2012 Convertible Senior Notes due 2016 (6.5%)	Dec. 31, 2011 Convertible Senior Notes due 2016 (6.5%)	Dec. 31, 2012 Not actively traded convertible notes	Dec. 31, 2012 Convertible Senior Notes due 2015 (7.0%)	Dec. 31, 2011 Convertible Senior Notes due 2015 (7.0%)	Dec. 31, 2012 Convertible Senior Notes due 2015 Series B (7.0%)	Dec. 31, 2011 Convertible Senior Notes due 2015 Series B (7.0%)	Dec. 31, 2012 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%)	Sep. 30, 2011 Convertible Senior Notes due 2013 (15.0%)	Dec. 31, 2011 Commercial Mortgages	Dec. 31, 2012 Estimate of Fair Value, Fair Value Disclosure Term Loans	Dec. 31, 2011 Estimate of Fair Value, Fair Value Disclosure Term Loans	Dec. 31, 2012 Estimate of Fair Value, Fair Value Disclosure Actively traded convertible notes	Dec. 31, 2011 Estimate of Fair Value, Fair Value Disclosure Actively traded convertible notes	Dec. 31, 2012 Estimate of Fair Value, Fair Value Disclosure Not actively traded convertible notes	Dec. 31, 2011 Estimate of Fair Value, Fair Value Disclosure Not actively traded convertible notes	Dec. 31, 2011 Estimate of Fair Value, Fair Value Disclosure Commercial Mortgages	Dec. 31, 2012 Fair Value, Measurements, Recurring Estimate of Fair Value, Fair Value Disclosure Senior Notes	Dec. 31, 2011 Fair Value, Measurements, Recurring Estimate of Fair Value, Fair Value Disclosure Senior Notes
Liabilities measured on a recurring basis
Term Loans																								$ 2,600	$ 2,500
Basis of interest rate on debt		LIBOR	LIBOR	LIBOR	LIBOR	LIBOR	LIBOR	LIBOR
Debt instrument, Interest spread on debt (as percent)		3.25%	3.75%	3.25%	4.25%	4.25%	2.25%	3.75%
Debt instrument, basis floor (as percent)		1.50%	1.50%	1.50%	1.50%	1.50%
Collateral for debt, Equity interest in Level 3 Financing, Inc's Canadian subsidiary (as a percent)	65.00%
Senior Notes																															5,700	4,800
Interest spread on debt, low end of range								3.75%
Interest spread on debt, high end of range								11.875%
Convertible Notes																										286	247	748	834
Debt instrument, stated interest rate (as a percent)									11.875%	11.875%	8.875%	6.50%	6.50%		7.00%	7.00%	7.00%	7.00%	15.00%	15.00%	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%
Fair value of commercial mortgage																														73
Carrying value of long term debt																							$ 65