Quarterly report pursuant to Section 13 or 15(d)

Debt and Secured Revolving Line of Credit (Narrative) (Details)

v3.8.0.1
Debt and Secured Revolving Line of Credit (Narrative) (Details)
3 Months Ended 9 Months Ended
Mar. 21, 2017
USD ($)
Dec. 30, 2017
USD ($)
Sep. 30, 2017
USD ($)
day
$ / shares
shares
Sep. 30, 2017
USD ($)
$ / shares
Sep. 24, 2016
USD ($)
Sep. 29, 2017
$ / shares
Sep. 19, 2017
USD ($)
Dec. 31, 2016
USD ($)
Sep. 28, 2016
USD ($)
Sep. 14, 2016
USD ($)
Apr. 14, 2015
USD ($)
Jun. 16, 2014
USD ($)
Feb. 26, 2014
USD ($)
Aug. 15, 2012
USD ($)
Debt Instrument [Line Items]                            
Repayments of Long-Term Debt       $ 70,000,000 $ 848,000,000                  
Stock Issued to partially settle long-term debt       38,000,000 $ 0                  
2.125% Convertible Senior Notes Due 2026 [Member]                            
Debt Instrument [Line Items]                            
Principal     $ 805,000,000 $ 805,000,000       $ 805,000,000 $ 105,000,000 $ 700,000,000        
Debt Conversion, Converted Instrument, Shares Issued | shares     125.0031                      
Debt Instrument, Convertible, Conversion Price | $ / shares     $ 8.00 $ 8.00                    
Debt Issuance Cost, Gross, Noncurrent               15,000,000            
Equity issuance costs               9,000,000            
Debt Instrument, Convertible, Remaining Life       108 months                    
Share price (in usd per share) | $ / shares           $ 12.75                
Debt Instrument, Interest Rate, Effective Percentage     8.00% 8.00%                    
Debt Instrument, Convertible, If-converted Value in Excess of Principal     $ 478,000,000                      
Debt Instrument, Interest Rate, Stated Percentage     2.125% 2.125%                    
2.125% Convertible Senior Notes Due 2026 [Member] | Debt Instrument, Redemption, Period One [Member]                            
Debt Instrument [Line Items]                            
Debt Instrument, Convertible, Threshold Trading Days | day     20                      
Debt Instrument, Convertible, Threshold Consecutive Trading Days | day     30                      
Debt Instrument, Convertible, Threshold Percentage of Stock Price Trigger     130.00%                      
2.125% Convertible Senior Notes Due 2026 [Member] | Debt Instrument, Redemption, Period Two [Member]                            
Debt Instrument [Line Items]                            
Debt Instrument, Convertible, Threshold Consecutive Trading Days | day     10                      
Debt Instrument, Convertible, Threshold Percentage of Stock Price Trigger     98.00%                      
Debt Instrument, Convertible, Conversion Period After Threshold Period Days | day     5                      
6.75% Senior Notes due 2019 [Member]                            
Debt Instrument [Line Items]                            
Principal                         $ 600,000,000  
Outstanding Aggregate Principal Amount     $ 191,000,000 $ 191,000,000                    
Debt Instrument, Interest Rate, Stated Percentage     6.75% 6.75%                    
Extinguishment of Debt, Amount       $ 5,000,000                    
7.50% Senior Notes due 2022 [Member]                            
Debt Instrument [Line Items]                            
Principal                           $ 500,000,000
Outstanding Aggregate Principal Amount     $ 347,000,000 $ 347,000,000                    
Debt Instrument, Interest Rate, Stated Percentage     7.50% 7.50%                    
Extinguishment of Debt, Amount       $ 3,000,000                    
7.00% Senior Notes due 2024 [Member]                            
Debt Instrument [Line Items]                            
Principal                       $ 500,000,000    
Outstanding Aggregate Principal Amount     $ 324,000,000 $ 324,000,000                    
Debt Instrument, Interest Rate, Stated Percentage     7.00% 7.00%                    
Repayments of Long-Term Debt     $ 28,000,000 $ 70,000,000                    
Stock Issued to partially settle long-term debt       26,000,000                    
Extinguishment of Debt, Amount     26,000,000 92,000,000                    
7.00% Senior Notes due 2024 [Member] | Subsequent Event [Member]                            
Debt Instrument [Line Items]                            
Extinguishment of Debt, Amount   $ 13,000,000                        
Revolving Credit Facility [Member]                            
Debt Instrument [Line Items]                            
Secured revolving line of credit, maximum borrowing capacity $ 500,000,000                          
Secured revolving line of credit, additional borrowing capacity 200,000,000                          
Secured revolving line of credit, outstanding balance     $ 70,000,000 $ 70,000,000       $ 0            
Secured revolving line of credit, interest rate     4.75% 4.75%                    
Letters of credit outstanding, amount     $ 19,000,000 $ 19,000,000                    
Secured revolving line of credit, remaining borrowing capacity     $ 327,000,000 $ 327,000,000                    
Debt Instrument, Repayment Period       90 days                    
Revolving Credit Facility [Member] | During first fiscal quarter [Member]                            
Debt Instrument [Line Items]                            
Secured revolving line of credit, maximum borrowing capacity             $ 220,000,000              
Revolving Credit Facility [Member] | During second and third fiscal quarter [Member]                            
Debt Instrument [Line Items]                            
Secured revolving line of credit, maximum borrowing capacity             300,000,000              
Revolving Credit Facility [Member] | During first day of fourth fiscal quarter through December 20 [Member]                            
Debt Instrument [Line Items]                            
Secured revolving line of credit, maximum borrowing capacity             300,000,000              
Revolving Credit Facility [Member] | From December 31 through the last day of fourth fiscal quarter [Member]                            
Debt Instrument [Line Items]                            
Secured revolving line of credit, maximum borrowing capacity             220,000,000              
Letter of Credit [Member]                            
Debt Instrument [Line Items]                            
Secured revolving line of credit, maximum borrowing capacity $ 45,000,000                   $ 75,000,000      
Maximum [Member] | Revolving Credit Facility [Member]                            
Debt Instrument [Line Items]                            
Debt Instrument, Percentage of Eligible Accounts Receivable 85.00%                          
Debt Instrument, Percentage of Certain Qualified Eligible Accounts Receivable 90.00%                          
Maximum [Member] | Revolving Credit Facility [Member] | During first day of fourth fiscal quarter through December 20 [Member]                            
Debt Instrument [Line Items]                            
Qualified Factor Account             $ 220,000,000