Long-Term Debt - Schedule of Long Term Debt (Details) - USD ($) $ in Millions		Jun. 30, 2015	Dec. 31, 2014
Long-term debt
Total Debt Obligations		$ 11,035	$ 11,366
Total Unamortized Discount		(17)	(33)
Carrying Value of Debt		11,018	11,333
Current portion of long-term debt		(17)	(349)
Long-Term Debt, less current portion		11,001	10,984
Senior Secured Term Loan
Long-term debt
Total Debt Obligations	[1]	4,611	4,611
Total Unamortized Discount		(17)	$ (21)
Tranche B-III 2019 Term Loan
Long-term debt
Debt Instrument, Face Amount		$ 815
Tranche B 2020 Term Loan
Long-term debt
Stated interest rate (as a percent)		4.00%
Total Debt Obligations		$ 1,796
Floating Rate Senior Notes due 2018 [Member]
Long-term debt
Stated interest rate (as a percent)		3.914%	3.826%
Total Debt Obligations		$ 300	$ 300
9.375% Senior Notes due 2019
Long-term debt
Total Debt Obligations		0	500
Total Unamortized Discount		0	(6)
8.125% Senior Notes due 2019
Long-term debt
Total Debt Obligations		0	1,200
Total Unamortized Discount		0	(6)
8.875% Senior Notes due 2019
Long-term debt
Total Debt Obligations		0	300
8.625% Senior Notes due 2020
Long-term debt
Total Debt Obligations		900	900
7.0% Senior Notes due 2020
Long-term debt
Total Debt Obligations		775	775
SeniorNotes6Point125PercentDue2021 [Member]
Long-term debt
Total Debt Obligations		640	640
5.37percent Senior Notes Due 2022 [Member]
Long-term debt
Total Debt Obligations		1,000	1,000
Senior Notes 5point75Percent Due 2022 [Member]
Long-term debt
Total Debt Obligations		600	600
Senior Notes 5point 625Percent Due 2023 [Member]
Long-term debt
Total Debt Obligations		500	0
Senior Notes 5point 125Percent Due 2023 [Member]
Long-term debt
Total Debt Obligations		700	0
Senior Notes 5point 375Percent Due 2025 [Member]
Long-term debt
Total Debt Obligations		800	0
7.0% Convertible Senior Notes due 2015
Long-term debt
Total Debt Obligations		0	58
7.0% Convertible Senior Notes due 2015 Series B
Long-term debt
Total Debt Obligations		0	275
Capital Leases
Long-term debt
Total Debt Obligations		209	207
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Long-term debt
Convertible Debt, Fair Value Disclosures		$ 0	$ 868

[1] * The $2 billion Tranche B Term Loan due 2022 had an interest rate of 4.5% as of December 31, 2014 and the $2 billion Tranche B-II Term Loan due 2022, which refinanced the Tranche B Term Loan due 2022 in full, had an interest rate of 3.5% as of June 30, 2015. The $815 million Tranche B-III Term Loan due 2019 and the $1.796 billion Tranche B Term Loan due 2020 each had an interest rate of 4.0% as of June 30, 2015 and December 31, 2014.