Quarterly report pursuant to Section 13 or 15(d)

Borrowings (Credit Facility) (Details)

v3.20.1
Borrowings (Credit Facility) (Details) - USD ($)
May 07, 2020
Mar. 31, 2020
Dec. 31, 2019
Oct. 03, 2016
Line of Credit Facility [Line Items]        
Total principal outstanding   $ 3,250,000,000 $ 3,185,000,000  
6.25% Senior Notes due 2023        
Line of Credit Facility [Line Items]        
Total principal outstanding   $ 650,000,000 650,000,000  
Debt instrument, interest rate, stated (as a percent)   6.25%   6.25%
6.125% Senior Notes due 2024        
Line of Credit Facility [Line Items]        
Total principal outstanding   $ 600,000,000 $ 600,000,000  
Debt instrument, interest rate, stated (as a percent)   6.125%   6.125%
New Credit Facility        
Line of Credit Facility [Line Items]        
Credit facility borrowing base   $ 2,500,000,000    
Increase limit   2,000,000,000.0    
Total principal outstanding   $ 1,350,000,000    
Interest rate at period end (as a percent)   2.83%    
Letters of credit outstanding   $ 17,700,000    
New Credit Facility | Subsequent Event        
Line of Credit Facility [Line Items]        
Leverage ratio 300.00%      
New Credit Facility | Federal Funds Rate | Subsequent Event        
Line of Credit Facility [Line Items]        
Debt instrument interest rate (as a percent) 0.50%      
New Credit Facility | LIBOR | Subsequent Event        
Line of Credit Facility [Line Items]        
Debt instrument interest rate (as a percent) 1.00%      
New Credit Facility | Minimum | Subsequent Event        
Line of Credit Facility [Line Items]        
Leverage ratio 100.00%      
Unused capacity, commitment fee (as a percent) 0.375%      
New Credit Facility | Minimum | Base Rate | Subsequent Event        
Line of Credit Facility [Line Items]        
Debt instrument interest rate (as a percent) 0.25%      
New Credit Facility | Minimum | Eurodollar | Subsequent Event        
Line of Credit Facility [Line Items]        
Debt instrument interest rate (as a percent) 1.25%      
New Credit Facility | Maximum | Subsequent Event        
Line of Credit Facility [Line Items]        
Leverage ratio 400.00%      
Unused capacity, commitment fee (as a percent) 0.50%      
New Credit Facility | Maximum | Base Rate | Subsequent Event        
Line of Credit Facility [Line Items]        
Debt instrument interest rate (as a percent) 1.25%      
New Credit Facility | Maximum | Eurodollar | Subsequent Event        
Line of Credit Facility [Line Items]        
Debt instrument interest rate (as a percent) 2.25%