Subsequent Event (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended	9 Months Ended
	Feb. 28, 2017	Apr. 30, 2017	Jul. 31, 2018	Jul. 31, 2017
Subsequent Event [Line Items]
Issuance of common stock			$ 0	$ 256
Volkswagen Truck and Bus GmbH [Member]
Subsequent Event [Line Items]
Stock Purchase Agreement, Ownership Percentage Transferred to Acquirer	19.90%
Stock Issued During Period, Shares, New Issues	16.2
Issuance of common stock		$ 256
Share Price		$ 15.76
Stock Purchase Agreement, Ownership Percentage Transferred to Acquirer, Pro Forma	16.60%