v3.3.1.900
Debt Credit Agreement (Details) - USD ($)
$ in Millions
3 Months Ended 12 Months Ended
May. 17, 2011
Mar. 31, 2014
Mar. 31, 2013
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Mar. 31, 2011
Line of Credit Facility [Line Items]                
Proceeds from Issuance of Long-term Debt $ 1,000              
Loss on extinguishment of debt   $ (34)   $ (58) $ (34) $ (39)    
Unamortized debt issuance costs       12 17      
Amended and Restated Credit Agreement                
Line of Credit Facility [Line Items]                
Payments of debt issuance costs     $ 14          
Loss on extinguishment of debt         (1) $ (39)    
Unamortized debt issuance costs       $ 13        
Amended and Restated Credit Agreement | Minimum                
Line of Credit Facility [Line Items]                
Contingent change in applicable rate       0.00%        
Amended and Restated Credit Agreement | Maximum                
Line of Credit Facility [Line Items]                
Contingent change in applicable rate       2.25%        
Amended and Restated Credit Agreement | Secured Debt                
Line of Credit Facility [Line Items]                
Letters of Credit Issued       $ 8        
Tranche A Term Loan, Due 2018 | Loans Payable                
Line of Credit Facility [Line Items]                
Unamortized debt issuance costs       1 2      
Borrowings       399 $ 398      
Tranche A Term Loan, Due 2018 | JPMorgan Chase Bank, N.A.                
Line of Credit Facility [Line Items]                
Line of Credit Facility, Increase, Additional Borrowings             $ 574  
Tranche A Term Loan, Due 2018 | JPMorgan Chase Bank, N.A. | Loans Payable                
Line of Credit Facility [Line Items]                
Borrowings       $ 400        
Tranche A Term Loan, Due 2018 | JPMorgan Chase Bank, N.A. | Loans Payable | LIBOR                
Line of Credit Facility [Line Items]                
Basis spread of variable rate       1.00% 1.00%      
Rates effective       1.3125%        
Tranche A Term Loan, Due 2018 | JPMorgan Chase Bank, N.A. | Loans Payable | Administrative Agents Alternate Base Rate                
Line of Credit Facility [Line Items]                
Basis spread of variable rate       0.00% 0.00%      
Tranche A Term Loan, Due 2018 | Loans Payable | JPMorgan Chase Bank, N.A.                
Line of Credit Facility [Line Items]                
Credit Agreement on Senior Secured Facilities     $ 575          
Revolver, Due 2018 | JPMorgan Chase Bank, N.A.                
Line of Credit Facility [Line Items]                
Line of Credit Facility, Increase, Additional Borrowings $ 2,400           $ 1,300  
Revolver, Due 2018 | Revolving Credit Facility | JPMorgan Chase Bank, N.A.                
Line of Credit Facility [Line Items]                
Credit Agreement on Senior Secured Facilities       $ 1,500        
Unamortized debt issuance costs       $ 12 $ 17      
Revolver, Due 2018 | Revolving Credit Facility | JPMorgan Chase Bank, N.A. | LIBOR                
Line of Credit Facility [Line Items]                
Basis spread of variable rate       1.00% 1.00%      
Revolver, Due 2018 | Revolving Credit Facility | JPMorgan Chase Bank, N.A. | Administrative Agents Alternate Base Rate                
Line of Credit Facility [Line Items]                
Basis spread of variable rate       0.00% 0.00%      
Revolver, Due 2018 | Revolving Credit Facility | JPMorgan Chase Bank, N.A. | Line of Credit | Administrative Agents Alternate Base Rate                
Line of Credit Facility [Line Items]                
Borrowings       $ 0        
Rates effective       0.00%        
Credit Agreement | Secured Debt | JPMorgan Chase Bank, N.A.                
Line of Credit Facility [Line Items]                
Credit Agreement on Senior Secured Facilities               $ 3,000
Covenant Compliance, Maximum Ratio of Indebtedness to EBITDA       275.00%