Fair Value of Financial Instruments - Liabilities, Recurring (Details) (Fair Value, Measurements, Recurring, USD $) In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Total Carrying Value in Consolidated Balance Sheet
Liabilities Recorded at Fair Value in the Financial Statements:
Interest Rate Swap Liabilities (included in other current and non-current liabilities)	$ 0	$ 12
Total Derivative Liabilities Recorded at Fair Value in the Financial Statements	0	12
Long-term Debt, including the current portion:
Term Loans	2,605	2,604
Senior Notes	6,200	5,198
Convertible Notes	475	474
Capital Leases and Other	78	86
Total Long-term Debt, including the current portion:	9,358	8,362
Unadjusted Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1)
Liabilities Recorded at Fair Value in the Financial Statements:
Interest Rate Swap Liabilities (included in other current and non-current liabilities)	0	0
Total Derivative Liabilities Recorded at Fair Value in the Financial Statements	0	0
Long-term Debt, including the current portion:
Term Loans	2,563	2,633
Senior Notes	5,531	5,673
Convertible Notes	0	0
Capital Leases and Other	0	0
Total Long-term Debt, including the current portion:	8,094	8,306
Significant Other Observable Inputs (Level 2)
Liabilities Recorded at Fair Value in the Financial Statements:
Interest Rate Swap Liabilities (included in other current and non-current liabilities)	0	12
Total Derivative Liabilities Recorded at Fair Value in the Financial Statements	0	12
Long-term Debt, including the current portion:
Term Loans	0	0
Senior Notes	0	0
Convertible Notes	818	647
Capital Leases and Other	78	86
Total Long-term Debt, including the current portion:	$ 896	$ 733