Income Taxes (Details) (USD $)	3 Months Ended			9 Months Ended
	Jul. 31, 2013	Jan. 31, 2013	Jul. 31, 2012	Jul. 31, 2013	Jul. 31, 2012	Oct. 31, 2012
Income Taxes
Effective tax rate (as a percent)	18.70%		2.20%	21.10%	(10.30%)
U.S. federal statutory income tax rate (as a percent)				35.00%
Net tax charge (benefit)	$ 63,000,000		$ (670,000,000)	$ (40,000,000)	$ (744,000,000)
Tax benefits from restructuring and acquisition charges	13,000,000		564,000,000	76,000,000	614,000,000
Tax charges (benefits) for various adjustments to estimated tax provisions, uncertain tax benefits and valuation allowances of U.S. and foreign jurisdictions	76,000,000			(64,000,000)
Tax benefits from miscellaneous discrete items			102,000,000		126,000,000
Tax benefit arising from the retroactive research and development credit		50,000,000
Tax charges related to a past uncertain tax position		150,000,000
Discrete income tax charge to record valuation allowances on certain deferred tax assets related to the enterprise services business			823,000,000		823,000,000
Tax benefits from reversals of deferred income tax liabilities on foreign earnings			827,000,000		827,000,000
Unrecognized tax benefits	3,000,000,000			3,000,000,000
Unrecognized tax benefits that would affect effective tax rate if realized	1,600,000,000			1,600,000,000
Accrued income tax payable for interest and penalties	169,000,000			169,000,000
Income tax examination, likelihood of no resolution period				12 months
Income tax examination, likelihood of conclusion period				12 months
Reasonably possible, reduction in existing unrecognized tax benefits within the next 12 months	129,000,000			129,000,000
Schedule of current and long-term deferred tax assets and deferred tax liabilities
Current deferred tax assets	3,841,000,000			3,841,000,000		3,783,000,000
Current deferred tax liabilities	(324,000,000)			(324,000,000)		(230,000,000)
Long-term deferred tax assets	1,541,000,000			1,541,000,000		1,581,000,000
Long-term deferred tax liabilities	(3,582,000,000)			(3,582,000,000)		(2,948,000,000)
Net deferred tax position	$ 1,476,000,000			$ 1,476,000,000		$ 2,186,000,000