Stockholders' Deficit - Schedule of Accumulated Other Comprehensive Loss, Net of Taxes (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Apr. 30, 2018	Apr. 30, 2017	Apr. 30, 2018	Apr. 30, 2017
Components of accumulated other comprehensive income, net of taxes
Balance at beginning of period			$ (3,408)
Other comprehensive loss before reclassifications			(225)
Reclassifications of (gains) losses into earnings			328
Reclassifications of curtailments, settlements and other into earnings			1
Balance at end of period	$ (1,863)		(1,863)
Accumulated other comprehensive loss
Components of accumulated other comprehensive income, net of taxes
Balance at beginning of period			(1,418)
Balance at end of period	(1,314)		(1,314)
Net unrealized gains on available-for-sale securities
Components of accumulated other comprehensive income, net of taxes
Balance at beginning of period			12
Other comprehensive loss before reclassifications			(4)
Reclassifications of (gains) losses into earnings			(5)
Reclassifications of curtailments, settlements and other into earnings			0
Balance at end of period	3		3
Net unrealized gains (losses) on cash flow hedges
Components of accumulated other comprehensive income, net of taxes
Balance at beginning of period			(240)
Other comprehensive loss before reclassifications	260	$ (60)	(221)	$ (232)
Reclassifications of (gains) losses into earnings	247	$ (9)	314	$ (76)
Reclassifications of curtailments, settlements and other into earnings			0
Balance at end of period	(147)		(147)
Unrealized components of defined benefit plans
Components of accumulated other comprehensive income, net of taxes
Balance at beginning of period			(1,190)
Other comprehensive loss before reclassifications			0
Reclassifications of (gains) losses into earnings			19
Reclassifications of curtailments, settlements and other into earnings			1
Balance at end of period	$ (1,170)		$ (1,170)