Fair Value of Financial Instruments - Liabilities, Non Recurring (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended		11 Months Ended	24 Months Ended	65 Months Ended	12 Months Ended
	Oct. 04, 2013	Aug. 01, 2013	Sep. 30, 2012	Oct. 04, 2013	Jul. 31, 2012	Dec. 31, 2014	Dec. 31, 2011	Dec. 31, 2013
Tranche B-II 2019 Term Loan
Liabilities measured on a recurring basis
Debt instrument, Interest spread on debt (as percent)	3.25%
Debt instrument, basis floor (as percent)						1.50%
Tranche B 2019 Term Loan
Liabilities measured on a recurring basis
Debt instrument, Interest spread on debt (as percent)		3.75%
Debt instrument, basis floor (as percent)						1.50%
Tranche B 2016 Term Loan
Liabilities measured on a recurring basis
Debt instrument, Interest spread on debt (as percent)		3.25%
Debt instrument, basis floor (as percent)						1.50%
Tranche B III Term Loan
Liabilities measured on a recurring basis
Debt instrument, Interest spread on debt (as percent)			4.25%
Debt instrument, basis floor (as percent)							1.50%
Tranche B II Term Loan
Liabilities measured on a recurring basis
Debt instrument, Interest spread on debt (as percent)				4.25%
Debt instrument, basis floor (as percent)							1.50%
Tranche A Term Loan
Liabilities measured on a recurring basis
Debt instrument, Interest spread on debt (as percent)					2.25%
Senior Notes 11 Point 875 Percent Due 2019 [Member]
Liabilities measured on a recurring basis
Debt instrument, stated interest rate (as a percent)						11.875%	11.875%
Senior Notes due 2019 (8.875%)
Liabilities measured on a recurring basis
Debt instrument, stated interest rate (as a percent)						8.875%
Convertible Senior Notes due 2016 (6.5%)
Liabilities measured on a recurring basis
Debt instrument, stated interest rate (as a percent)						6.50%	6.50%
Not actively traded convertible notes
Liabilities measured on a recurring basis
Security coupon rates used for valuation, lowest interest rate						7.00%
Convertible Senior Notes 7 Percent Due 2015 [Member]
Liabilities measured on a recurring basis
Debt instrument, stated interest rate (as a percent)						7.00%	7.00%
Convertible Senior Notes due 2015 Series B (7.0%)
Liabilities measured on a recurring basis
Debt instrument, stated interest rate (as a percent)						7.00%	7.00%
Convertible Senior Notes due 2013 (15.0%)
Liabilities measured on a recurring basis
Debt instrument, stated interest rate (as a percent)						15.00%	15.00%
Estimate of Fair Value, Fair Value Disclosure | Term Loans
Liabilities measured on a recurring basis
Term Loans						4,600		$ 2,600
Estimate of Fair Value, Fair Value Disclosure | Not actively traded convertible notes
Liabilities measured on a recurring basis
Convertible Notes						868		647
Fair Value, Measurements, Recurring | Estimate of Fair Value, Fair Value Disclosure | Senior Notes
Liabilities measured on a recurring basis
Senior Notes						6,500		$ 5,700