v3.19.3
Long-Term Debt and Revolving Credit Arrangements - Narrative (Details) - USD ($)
1 Months Ended 3 Months Ended 9 Months Ended 12 Months Ended
Sep. 30, 2019
Oct. 31, 2018
Apr. 30, 2018
Jul. 31, 2016
Sep. 30, 2019
Jun. 30, 2019
Sep. 30, 2018
Sep. 30, 2019
Sep. 30, 2018
Dec. 31, 2015
Dec. 31, 2018
Jun. 13, 2018
Debt Instrument [Line Items]                        
Total debt $ 5,797,000,000       $ 5,797,000,000     $ 5,797,000,000     $ 7,491,000,000  
Embedded derivative liability (income) expense         $ 0 $ (117,000,000) $ 89,000,000 $ (58,000,000) $ 491,000,000      
Secured Loans | 2016 Senior Secured Term Loan                        
Debt Instrument [Line Items]                        
Proceeds from issuance of secured debt       $ 1,200,000,000                
Debt discount       23,000,000                
Debt issuance costs       $ 13,000,000                
Effective Interest Rate 6.10%       6.10%     6.10%       6.10%
Total debt $ 1,116,000,000       $ 1,116,000,000     $ 1,116,000,000     1,124,000,000  
Secured Loans | 2018 Senior Secured Term Loan                        
Debt Instrument [Line Items]                        
Proceeds from issuance of secured debt     $ 1,500,000,000                  
Debt discount     8,000,000                  
Debt issuance costs     $ 15,000,000                  
Effective Interest Rate 6.20%       6.20%     6.20%        
Total debt $ 1,481,000,000       $ 1,481,000,000     $ 1,481,000,000     1,493,000,000  
Convertible Notes | 2021 Convertible Notes                        
Debt Instrument [Line Items]                        
Debt discount                   $ 1,100,000,000    
Debt issuance costs                   $ 1,000,000    
Effective Interest Rate 23.50%       23.50%     23.50%   23.50%    
Total debt $ 0       $ 0     $ 0     1,844,000,000  
Proceeds from issuance of convertible debt                   $ 1,700,000,000    
Stated interest rate                   2.50%    
Duration for interest type payment election                   4 years    
Interest rate increase during final 2 year initial term                   12.50%    
Embedded derivative liability (income) expense         $ 0   80,000,000 $ (20,000,000) 419,000,000      
Convertible Notes | 2021 Convertible Notes | Minimum                        
Debt Instrument [Line Items]                        
Interest rate during maturity extension period                   3.50%    
Discount on conversion price rate                   18.00%    
Convertible Notes | 2021 Convertible Notes | Maximum                        
Debt Instrument [Line Items]                        
Interest rate during maturity extension period                   12.50%    
Discount on conversion price rate                   30.50%    
Convertible Notes | 2022 Convertible Notes                        
Debt Instrument [Line Items]                        
Proceeds from issuance of secured debt                   $ 949,000,000    
Debt discount                   312,000,000    
Debt issuance costs                   $ 100,000    
Effective Interest Rate 13.70%       13.70%     13.70%        
Total debt $ 0       $ 0     $ 0     1,030,000,000  
Extension period                   1 year    
Stated interest rate                   2.50%    
Convertible Notes, internal rate of return                   8.00%    
Redemption period                   3 years    
Embedded derivative liability (income) expense         $ 0   $ 9,000,000 $ (38,000,000) $ 72,000,000      
Convertible Notes | 2022 Convertible Notes | Minimum                        
Debt Instrument [Line Items]                        
Discount on conversion price rate                   8.10%    
Convertible Notes | 2022 Convertible Notes | Maximum                        
Debt Instrument [Line Items]                        
Discount on conversion price rate                   44.50%    
Senior Note                        
Debt Instrument [Line Items]                        
Aggregate principal amount   $ 2,000,000,000.0                    
Senior Note | 2023 Senior Note                        
Debt Instrument [Line Items]                        
Debt issuance costs   $ 9,000,000                    
Effective Interest Rate 7.70%       7.70%     7.70%        
Total debt $ 500,000,000       $ 500,000,000     $ 500,000,000     500,000,000  
Stated interest rate   7.50%                    
Debt instrument term   5 years                    
Aggregate principal amount   $ 500,000,000                    
Senior Note | 2023 Senior Note | Level 2                        
Debt Instrument [Line Items]                        
Debt instrument, fair value disclosure $ 503,000,000       $ 503,000,000     $ 503,000,000        
Senior Note | 2026 Senior Note                        
Debt Instrument [Line Items]                        
Effective Interest Rate 8.10%       8.10%     8.10%        
Total debt $ 1,500,000,000       $ 1,500,000,000     $ 1,500,000,000     1,500,000,000  
Stated interest rate   8.00%                    
Debt instrument term   8 years                    
Aggregate principal amount   $ 1,500,000,000                    
Senior Note | 2026 Senior Note | Level 2                        
Debt Instrument [Line Items]                        
Debt instrument, fair value disclosure 1,500,000,000       1,500,000,000     1,500,000,000        
Senior Note | 2027 Senior Note                        
Debt Instrument [Line Items]                        
Debt issuance costs $ 11,000,000       $ 11,000,000     $ 11,000,000        
Effective Interest Rate 7.70%       7.70%     7.70%        
Total debt $ 1,200,000,000       $ 1,200,000,000     $ 1,200,000,000     0  
Stated interest rate 7.50%       7.50%     7.50%        
Debt instrument term 8 years                      
Aggregate principal amount $ 1,200,000,000       $ 1,200,000,000     $ 1,200,000,000        
Senior Note | 2027 Senior Note | Level 2                        
Debt Instrument [Line Items]                        
Debt instrument, fair value disclosure 1,200,000,000       1,200,000,000     1,200,000,000        
Line of Credit | Revolving Credit Facility                        
Debt Instrument [Line Items]                        
Borrowing capacity 2,300,000,000       2,300,000,000     $ 2,300,000,000        
Credit facility, term               5 years        
Line of credit balance 0       0     $ 0        
Line of Credit | Letters of Credit                        
Debt Instrument [Line Items]                        
Letters of credit outstanding 561,000,000       561,000,000     561,000,000     470,000,000  
Letters of credit outstanding that will reduce the available credit under facilities $ 204,000,000       $ 204,000,000     $ 204,000,000     $ 166,000,000