v3.7.0.1
Unearned Revenue and Performance Obligations (Details) - USD ($)
$ in Millions
3 Months Ended
Apr. 30, 2017
Apr. 30, 2016
Deferred Revenue Disclosure [Abstract]    
Subscription revenue recognized that was included in total unearned revenue balance at beginning of period $ 361 $ 251
Revenue is expected to be recognized from remaining performance obligations for subscription contracts $ 4,000  
Remaining performance obligations to be recognized in the next 2 years 66.67%  
Recognition period 24 months