Taxes on Earnings - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Apr. 30, 2018	Apr. 30, 2017	Apr. 30, 2018	Apr. 30, 2017	Oct. 31, 2017
Income Tax Disclosure [Abstract]
Effective tax rate (as a percent)	832.80%	523.00%	401.70%	150.70%
Net income tax charges (benefits)	$ (1,000)	$ (556)	$ (3,200)	$ 525
Pre-Separation tax matters	1,100		2,000
Net excess tax benefits related to stock compensation	28		42
Income tax benefit on restructuring charges, separation costs, transformation costs and acquisition and other related charges	18	36	62	67
Income tax benefits from U.S. tax reform	125		681
Benefit from liquidation of business			203
Foreign tax credit			239
Accrued divestiture tax		110		110
Valuation allowance		473		473
Tax indemnification		$ 13		$ 31
Transition tax	100		1,100
Provisional tax benefit from Tax Cut and Jobs Act			1,800
Unrecognized tax benefits	8,800		8,800		$ 11,300
Unrecognized tax benefits that would affect effective tax rate if realized	1,000		1,000		3,000
Decrease from settlements with IRS			2,500
Accrued income tax for interest and penalties	165		$ 165		$ 304
Likelihood of no resolution period			12 months
Reasonably possible reduction in existing unrecognized tax benefits within the next 12 months	$ 85		$ 85
Likelihood of conclusion period for certain federal, foreign and state tax issues			12 months