Stockholders' Deficit - Schedule of Accumulated Other Comprehensive Loss, Net of Taxes (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Apr. 30, 2020	Apr. 30, 2019	Apr. 30, 2020	Apr. 30, 2019
Components of accumulated other comprehensive income, net of taxes
Balance at beginning of period			$ (1,193)
Other comprehensive income (loss) before reclassifications			229
Reclassifications of (gains) losses into earnings			(55)
Balance at end of period	$ (743)		(743)
Accumulated other comprehensive loss
Components of accumulated other comprehensive income, net of taxes
Balance at beginning of period			(1,225)
Balance at end of period	(1,050)		(1,050)
Net unrealized gains on available-for-sale debt securities
Components of accumulated other comprehensive income, net of taxes
Balance at beginning of period			9
Other comprehensive income (loss) before reclassifications	(2)	$ 0	(1)	$ 0
Reclassifications of (gains) losses into earnings	0	3	0	3
Balance at end of period	8		8
Net unrealized gains (losses) on cash flow hedges
Components of accumulated other comprehensive income, net of taxes
Balance at beginning of period			172
Other comprehensive income (loss) before reclassifications		162		75
Reclassifications of (gains) losses into earnings		$ 4		$ (153)
Net unrealized gains (losses) on cash flow hedges
Components of accumulated other comprehensive income, net of taxes
Other comprehensive income (loss) before reclassifications	198		242
Reclassifications of (gains) losses into earnings	(37)		(86)
Balance at end of period	328		328
Unrealized components of defined benefit plans
Components of accumulated other comprehensive income, net of taxes
Balance at beginning of period			(1,410)
Other comprehensive income (loss) before reclassifications			(1)
Reclassifications of (gains) losses into earnings			31
Balance at end of period	(1,379)		(1,379)
Reclassifications of settlements into earnings
Components of accumulated other comprehensive income, net of taxes
Reclassifications of (gains) losses into earnings			1
Change in cumulative translation adjustment
Components of accumulated other comprehensive income, net of taxes
Balance at beginning of period			4
Other comprehensive income (loss) before reclassifications			(11)
Reclassifications of (gains) losses into earnings			0
Balance at end of period	$ (7)		$ (7)