Leases (Future Minimum Lease Payments) (Details) (USD $)
In Millions, unless otherwise specified
Jan. 31, 2015
Leases [Abstract]  
2013, Operating $ 237
2014, Operating 216
2015, Operating 185
2016, Operating 153
2017, Operating 132
Thereafter, Operating 1,896
Less: sublease payments, Operating (39)
Total minimum lease payments, Operating 2,780
2013, Capital 33
2014, Capital 27
2015, Capital 10
2016, Capital 0
2017, Capital 0
Thereafter, Capital 0
Total minimum lease payments, Capital 70
Less: amounts representing interest (4)
Present value of net minimum lease obligations $ 66