Income Taxes (Narrative) (Details) - USD ($)
3 Months Ended 9 Months Ended
Oct. 31, 2020
Nov. 02, 2019
Oct. 31, 2020
Nov. 02, 2019
Income Tax Contingency [Line Items]        
Income tax expense/(benefit) $ 1,000,000 $ (1,000,000) $ (66,000,000) $ 5,000,000
Income tax benefit due to release of valuation allowance     65,000,000  
Deferred State and Local Income Tax Expense (Benefit)     3,000,000  
Net operating loss carryforwards 2,700,000,000   2,700,000,000  
Federal unused interest deductions that do not expire subject to interest limitation 615,000,000   615,000,000  
Deferred Tax Asset, Interest Carryforward 473,000,000   473,000,000  
Tax credit carryforwards 76,000,000   $ 76,000,000  
Valuation allowance, methodologies and assumptions     In assessing the need for the valuation allowance, we considered both positive and negative evidence related to the likelihood of realization of the deferred tax assets. As a result of our periodic assessment, our estimate of the realization of deferred tax assets is solely based on the future reversals of existing taxable temporary differences and tax credit carryforwards.  
Increase to tax valuation allowance for deferred tax assets 86,000,000      
Federal, State And Foreign        
Income Tax Contingency [Line Items]        
State and foreign tax expenses     $ (1,000,000)  
Amortization of certain indefinite lived intangible assets        
Income Tax Contingency [Line Items]        
State and foreign tax expenses (1,000,000)   (3,000,000)  
Federal tax authority        
Income Tax Contingency [Line Items]        
Valuation allowance 866,000,000   866,000,000  
State Tax Authority        
Income Tax Contingency [Line Items]        
Valuation allowance $ 274,000,000   $ 274,000,000