v3.20.2
Debt 144A due 2028 and Credit Agreement (Details) - USD ($)
9 Months Ended
May 13, 2020
Apr. 02, 2020
Apr. 01, 2020
Mar. 25, 2020
Feb. 07, 2020
Feb. 05, 2020
Sep. 30, 2020
Sep. 30, 2019
Mar. 31, 2020
Aug. 01, 2012
Debt Instrument [Line Items]                    
Debt instrument, face amount           $ 1,200,000,000        
Proceeds from debt issuance           $ 1,168,000,000 $ 2,400,000,000 $ 0    
Cash     $ 500,000,000           $ 60,000,000  
Separation payment to former parent company (A)     $ 728,000,000       728,000,000      
Senior Secured Notes | Second-Lien Notes due 2028, 6.125%                    
Debt Instrument [Line Items]                    
Debt instrument, face amount         $ 600,000,000          
Fixed interest rate         6.125%          
Proceeds from debt issuance         $ 593,000,000          
Debt, carrying value             1,277,000,000      
Senior Secured Notes | First-Lien Notes due 2025, 6.000%                    
Debt Instrument [Line Items]                    
Debt instrument, face amount $ 700,000,000                  
Fixed interest rate 6.00%                  
Proceeds from debt issuance $ 691,000,000                  
Debt Issuance Costs, Net             15,000,000      
Unamortized Debt Issuance Expense             12,000,000      
Interest Expense, Other Long-term Debt             19,000,000      
Write off of Deferred Debt Issuance Cost             3,000,000      
Debt, carrying value             1,365,000,000      
Senior Secured Loans | First-Lien Term B Loan Facility                    
Debt Instrument [Line Items]                    
Debt instrument, face amount 600,000,000     $ 600,000,000            
Debt instrument, term       7 years            
Proceeds from debt issuance       $ 575,000,000            
Debt Issuance Costs, Net             30,000,000      
Unamortized Debt Issuance Expense             14,000,000      
Interest Expense, Other Long-term Debt             19,000,000      
Write off of Deferred Debt Issuance Cost             16,000,000      
Senior Secured Credit Facility | First-Lien Revolving Credit Facility | Revolving Credit Facility                    
Debt Instrument [Line Items]                    
Debt instrument, face amount       $ 1,000            
Debt instrument, term       5 years            
Basis spread on variable rate   2.00%                
Proceeds from revolving credit facility $ 500,000,000 $ 500,000,000                
Debt Issuance Costs, Net             30,000,000      
Unamortized Debt Issuance Expense             14,000,000      
Interest Expense, Other Long-term Debt             19,000,000      
Write off of Deferred Debt Issuance Cost             16,000,000      
Senior Secured Credit Facility | ABL Credit Agreement | Revolving Credit Facility | Deutsche Bank AG New York Branch                    
Debt Instrument [Line Items]                    
Debt Issuance Costs, Net             15,000,000      
Unamortized Debt Issuance Expense             12,000,000      
Interest Expense, Other Long-term Debt             19,000,000      
Write off of Deferred Debt Issuance Cost             3,000,000      
Revolving credit facility, current borrowing capacity             681,000,000      
Required fixed charge coverage ratio 1.00                  
Senior Secured Credit Facility | ABL Credit Agreement | Revolving Credit Facility | LIBOR | Deutsche Bank AG New York Branch                    
Debt Instrument [Line Items]                    
Basis spread on variable rate 1.00%                  
Bonds [Member] | Midwestern Disaster Area Revenue Bonds Series 2012 [Member]                    
Debt Instrument [Line Items]                    
Debt instrument, face amount                   $ 250,000,000
Secured Debt and Line of Credit [Member] | First-Lien Revolving Credit Facility and Second-Lien Notes due 2028, 6.125% [Member]                    
Debt Instrument [Line Items]                    
Debt Issuance Costs, Net             $ 42,000,000      
Minimum | Senior Secured Notes | Second-Lien Notes due 2028, 6.125%                    
Debt Instrument [Line Items]                    
Required prior notice for debt redemption, term         10 days          
Minimum | Senior Secured Notes | First-Lien Notes due 2025, 6.000%                    
Debt Instrument [Line Items]                    
Required prior notice for debt redemption, term 10 days                  
Minimum | Senior Secured Credit Facility | ABL Credit Agreement | Revolving Credit Facility | LIBOR | Deutsche Bank AG New York Branch                    
Debt Instrument [Line Items]                    
Fixed interest rate 0.75%                  
Maximum | Senior Secured Notes | Second-Lien Notes due 2028, 6.125%                    
Debt Instrument [Line Items]                    
Required prior notice for debt redemption, term         60 days          
Maximum | Senior Secured Notes | First-Lien Notes due 2025, 6.000%                    
Debt Instrument [Line Items]                    
Required prior notice for debt redemption, term 60 days                  
Redemption prior to February 15, 2023 | Senior Secured Notes | Second-Lien Notes due 2028, 6.125%                    
Debt Instrument [Line Items]                    
Debt redemption percentage         100.00%          
Debt redemption, basis spread on discount rate 5000.00%                  
Debt redemption, additional make-whole charge         1.00%          
Redemption prior to February 15, 2023 | Senior Secured Notes | First-Lien Notes due 2025, 6.000%                    
Debt Instrument [Line Items]                    
Debt redemption percentage 100.00%                  
Debt redemption, basis spread on discount rate         5000.00%          
Debt redemption, additional make-whole charge 1.00%                  
Redemption prior to February 15, 2023; limited to 40% of aggregate principal | Senior Secured Notes | Second-Lien Notes due 2028, 6.125%                    
Debt Instrument [Line Items]                    
Debt redemption percentage         106.125%          
Redemption limitation based on aggregate principal         40.00%          
Minimum aggregate principal following redemption         60.00%          
Maximum term allowed for redemption following offering         120 days          
Redemption prior to February 15, 2023; limited to 40% of aggregate principal | Senior Secured Notes | First-Lien Notes due 2025, 6.000%                    
Debt Instrument [Line Items]                    
Debt redemption percentage 106.00%                  
Redemption limitation based on aggregate principal 40.00%                  
Minimum aggregate principal following redemption 60.00%                  
Maximum term allowed for redemption following offering 120 days                  
Redemption after February 14, 2023 | Senior Secured Notes | Second-Lien Notes due 2028, 6.125%                    
Debt Instrument [Line Items]                    
Debt redemption percentage         103.063%          
Redemption after February 14, 2023 | Senior Secured Notes | First-Lien Notes due 2025, 6.000%                    
Debt Instrument [Line Items]                    
Debt redemption percentage 103.00%                  
Redemption upon change in control | Senior Secured Notes | Second-Lien Notes due 2028, 6.125%                    
Debt Instrument [Line Items]                    
Debt redemption percentage         101.00%          
Redemption upon change in control | Senior Secured Notes | First-Lien Notes due 2025, 6.000%                    
Debt Instrument [Line Items]                    
Debt redemption percentage 101.00%