Stockholders' Equity - Changes and Reclassifications Related to Other Comprehensive Income (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
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other comprehensive income, net of taxes	$ 159	$ 1	$ 99	$ 476
Net unrealized gains (losses) on available-for-sale securities
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other comprehensive income (loss) before reclassifications			1
Gains reclassified into earnings			(9)
Change in net unrealized (losses) gains on cash flow hedges
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other comprehensive income (loss) before reclassifications			(85)
Gains reclassified into earnings			105
Change in unrealized components of defined benefit plans
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other comprehensive income (loss) before reclassifications			1
Gains reclassified into earnings			85
Change in cumulative translation adjustment
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other comprehensive income (loss) before reclassifications			1
Gains reclassified into earnings			0
Reclassifications of gains (losses) into earnings | Net unrealized gains (losses) on available-for-sale securities
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other comprehensive income (loss) before reclassifications	0	(4)	1	(18)
Gains reclassified into earnings	(17)	0	(9)	0
Other comprehensive income, net of taxes	(17)	(4)	(8)	(18)
Reclassifications of gains (losses) into earnings | Change in net unrealized (losses) gains on cash flow hedges
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other comprehensive income (loss) before reclassifications	71	8	(85)	113
Gains reclassified into earnings	79	(70)	105	(201)
Other comprehensive income, net of taxes	150	(62)	20	(88)
Reclassifications of gains (losses) into earnings | Change in unrealized components of defined benefit plans
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other comprehensive income, net of taxes	48	78	86	617
Reclassifications of gains (losses) into earnings | Gains arising during the period
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Gains reclassified into earnings	0	10	1	465
Reclassifications of gains (losses) into earnings | Amortization of actuarial loss and prior service benefit
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Gains reclassified into earnings	46	72	90	163
Reclassifications of gains (losses) into earnings | Curtailments, settlements and other
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other comprehensive income, net of taxes	2	(4)	(5)	(11)
Reclassifications of gains (losses) into earnings | Change in cumulative translation adjustment
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other comprehensive income, net of taxes	$ (22)	$ (11)	$ 1	$ (35)