Long-Term Debt - Schedule of Long Term Debt (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013		Dec. 31, 2012
Long-term debt
Total Debt Obligations	$ 8,591		$ 8,780
Total Unamortized Discount	(45)		(48)
Carrying Value of Debt	8,546		8,732
Less current portion	(38)		(216)
Long-Term Debt, less current portion	8,508		8,516
Term Loans
Long-term debt
Total Debt Obligations	2,612	[1]	2,614	[1]
Total Unamortized Discount	(10)		(11)
Floating Rate Senior Notes due 2015
Long-term debt
Debt instrument, stated interest rate (as a percent)	4.215%		4.469%
Total Debt Obligations	300		300
Senior Notes due 2018 (10.0%)
Long-term debt
Debt instrument, stated interest rate (as a percent)	10.00%		10.00%
Total Debt Obligations	640		640
Total Unamortized Discount	(9)		(10)
Senior Notes due 2019 (11.875%)
Long-term debt
Debt instrument, stated interest rate (as a percent)	11.875%		11.875%
Total Debt Obligations	605		605
Total Unamortized Discount	(9)		(9)
Senior Notes due 2019 (9.375%)
Long-term debt
Debt instrument, stated interest rate (as a percent)	9.375%		9.375%
Total Debt Obligations	500		500
Total Unamortized Discount	(8)		(8)
Senior Notes due 2019 (8.125%)
Long-term debt
Debt instrument, stated interest rate (as a percent)	8.125%		8.125%
Total Debt Obligations	1,200		1,200
Total Unamortized Discount	(8)		(8)
Senior Notes due 2019 (8.875%)
Long-term debt
Debt instrument, stated interest rate (as a percent)	8.875%		8.875%
Total Debt Obligations	300		300
Senior Notes due 2020 (8.625%)
Long-term debt
Debt instrument, stated interest rate (as a percent)	8.625%		8.625%
Total Debt Obligations	900		900
Senior Notes due 2020 (7.0%)
Long-term debt
Debt instrument, stated interest rate (as a percent)	7.00%		7.00%
Total Debt Obligations	775		775
Convertible Senior Notes due 2013 (15.0%)
Long-term debt
Debt instrument, stated interest rate (as a percent)	15.00%		15.00%
Total Debt Obligations	0		172
Convertible Senior Notes due 2015 (7.0%)
Long-term debt
Debt instrument, stated interest rate (as a percent)	7.00%		7.00%
Total Debt Obligations	200		200
Total Unamortized Discount	(1)		(2)
Convertible Senior Notes due 2015 Series B (7.0%)
Long-term debt
Debt instrument, stated interest rate (as a percent)	7.00%		7.00%
Total Debt Obligations	275		275
Convertible Senior Notes due 2016 (6.5%)
Long-term debt
Debt instrument, stated interest rate (as a percent)	6.50%		6.50%
Total Debt Obligations	201		201
Capital Leases
Long-term debt
Total Debt Obligations	76		86
Other
Long-term debt
Total Debt Obligations	$ 7		$ 12

[1] * The $597 million Tranche B 2016 Term Loan due 2016, the $815 million Tranche B 2019 Term Loan due 2019 and the $1.2 billion Tranche B-II 2019 Term Loan due 2019 had interest rates of 4.75%, 5.25% and 4.75% as of March 31, 2013, respectively. The $599 million Tranche B 2016 Term Loan due 2016, the $815 million Tranche B 2019 Term Loan due 2019 and the $1.2 billion Tranche B-II 2019 Term Loan due 2019 had interest rates of 4.75%, 5.25% and 4.75% as of December 31, 2012, respectively. The Tranche B 2016 Term Loan requires repayment of 0.25% of the original $600 million aggregate principal amount on the last day of each March, June, September and December, beginning with December 31, 2012 and ending with such last day to occur prior to maturity.