Contingencies Schedule of FCPA Expenses (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Oct. 31, 2016	Oct. 31, 2015	Oct. 31, 2016	Oct. 31, 2015
Foreign Corrupt Practices Act Expenses [Line Items]
Foreign corrupt practices act related expenses	$ 29	$ 30	$ 82	$ 93
Compliance programs and organizational enhancements
Foreign Corrupt Practices Act Expenses [Line Items]
Foreign corrupt practices act related expenses	5	8	14	23
Inquiry and investigation expense
Foreign Corrupt Practices Act Expenses [Line Items]
Foreign corrupt practices act related expenses	$ 24	$ 22	$ 68	$ 70