Long-Term Debt (Details) (USD $)
In Millions, unless otherwise specified
1 Months Ended 3 Months Ended 9 Months Ended 1 Months Ended 1 Months Ended 1 Months Ended 9 Months Ended 1 Months Ended 0 Months Ended 9 Months Ended 1 Months Ended 9 Months Ended 1 Months Ended 9 Months Ended
Oct. 31, 2014
Nov. 01, 2014
Nov. 02, 2013
Nov. 01, 2014
Nov. 02, 2013
Aug. 02, 2014
Sep. 30, 2014
Senior Notes 8.125% due 2019 [Member]
Oct. 31, 2014
Medium-Term Notes 6.875% due 2015 [Member]
Nov. 01, 2014
Medium-Term Notes 6.875% due 2015 [Member]
Aug. 02, 2014
Medium-Term Notes 6.875% due 2015 [Member]
Oct. 31, 2014
Debentures 7.65% due 2016 [Member]
Nov. 01, 2014
Debentures 7.65% due 2016 [Member]
Aug. 02, 2014
Debentures 7.65% due 2016 [Member]
Oct. 31, 2014
Debentures 7.95% due 2017 [Member]
Nov. 01, 2014
Debentures 7.95% due 2017 [Member]
Aug. 02, 2014
Debentures 7.95% due 2017 [Member]
Nov. 02, 2013
Unamortized Debt Issue Costs [Member]
Oct. 31, 2014
2014 Debt Defeasance [Member]
Jun. 05, 2013
2013 Tender Offer [Member]
May 22, 2013
2013 Tender Offer [Member]
Nov. 01, 2014
2013 Tender Offer [Member]
Nov. 02, 2013
2013 Tender Offer [Member]
Oct. 31, 2014
Premium Paid [Member]
Nov. 02, 2013
Premium Paid [Member]
Oct. 31, 2014
Reacquisition Costs [Member]
Nov. 02, 2013
Reacquisition Costs [Member]
Debt Instrument, Interest Rate, Stated Percentage             8.125%                     6.875%       7.125%        
Net proceeds from issuance of long-term debt   $ 393 $ 0 $ 893 $ 2,180   $ 393                                      
Tender Premium               67.50 [1]     105.00 [1]     97.50 [1]                        
Principal Amount Tendered ($ in millions) 456             140     122     194                        
Extinguishment of debt 327             140     122     65       64 2 243            
Unsecured long-term debt   358   358   685 400   60 200   78 200   220 285                    
Early repayments of unsecured debt 362                                   3 352            
Accrued interest expense on debt accepted for purchase 6                                                  
Loss on extinguishment of debt $ 30 $ 34 $ 0 $ 34 $ 114                       $ 2 $ 4       $ 114 $ 29 $ 110 $ 1 $ 2
Commencement of Tender Offer                                         Apr. 30, 2013          
Percentage of Principal Amount Redeemed in Tender Offer                                       95.41%            
[1] Per $1,000 principal amount of Securities