Earnings/(Loss) per Share (Details) - USD ($)
$ / shares in Units, shares in Millions, $ in Millions
3 Months Ended 9 Months Ended
Oct. 31, 2015
Nov. 01, 2014
Oct. 31, 2015
Nov. 01, 2014
Earnings Per Share [Abstract]        
Net income/(loss) $ (137) $ (188) $ (442) $ (712)
Weighted average common shares outstanding (basic shares) 306.0 305.3 305.8 305.1
Weighted average shares assuming dilution (diluted shares) 306.0 305.3 305.8 305.1
Basic (in dollars per share) $ (0.45) $ (0.62) $ (1.45) $ (2.33)
Diluted (in dollars per share) $ (0.45) $ (0.62) $ (1.45) $ (2.33)
Stock options, restricted stock awards and warrant 32.0 26.9 31.8 26.1