Contingencies Schedule of FCPA Expenses (Details) - USD ($) $ in Millions	3 Months Ended
	Apr. 30, 2017	Apr. 30, 2016
Foreign Corrupt Practices Act Expenses [Line Items]
Foreign corrupt practices act related expenses	$ 16	$ 25
Compliance programs and organizational enhancements
Foreign Corrupt Practices Act Expenses [Line Items]
Foreign corrupt practices act related expenses	3	4
Inquiry and investigation expense
Foreign Corrupt Practices Act Expenses [Line Items]
Foreign corrupt practices act related expenses	$ 13	$ 21