Balance Sheet Detail (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended			9 Months Ended
	Jul. 31, 2011		Jan. 30, 2011	Jul. 31, 2011		Oct. 31, 2010
Inventories
Customer service spares	$ 328			$ 328		$ 324
Raw materials	408			408		260
Work-in-process	457			457		500
Finished goods	656			656		463
Total Inventories	1,849	[1]		1,849	[1]	1,547	[1]
Property, Plant and Equipment, Net
Land and improvements	169			169		227
Buildings and improvements	1,170			1,170		1,234
Demonstration and manufacturing equipment	679			679		670
Furniture, fixtures and other equipment	715			715		719
Construction in progress	24			24		19
Gross property, plant and equipment	2,757			2,757		2,869
Accumulated depreciation	(1,903)			(1,903)		(1,906)
Net property, plant and equipment	854	[1]		854	[1]	963	[1]
Accounts Payable and Accrued Expenses
Accounts payable	656			656		658
Compensation and employee benefits	405			405		435
Warranty	188			188		155
Dividends payable	105			105		93
Other accrued taxes	76			76		99
Restructuring reserve	16			16		104
Interest Payable	15			15		1
Other	192			192		221
Total Accounts Payable and Accrued Expenses	1,653	[1]		1,653	[1]	1,766	[1]
Customer Deposits and Deferred Revenue
Customer deposits	442			442		407
Deferred revenue	905			905		440
Total Customer Deposits and Deferred Revenue	1,347	[1]		1,347	[1]	847	[1]
Balance Sheet Detail (Textuals) [Abstract]
Inventory at customer locations included in finished goods	281			281		148
Evaluation inventory	145			145		117
Proceeds from sale of property	60		39	126
Loss on proceeds from sale of property	28		(1)
Proceeds of certain assets held for sale, net of cash sold	27			27
Contractual termination obligation charges	$ 10			$ 10		$ 40
Furniture, fixtures and other equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life, Minimum	3			3
Property, Plant and Equipment, Useful Life, Maximum	15			15
Demonstration and manufacturing equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life, Minimum	3			3
Property, Plant and Equipment, Useful Life, Maximum	5			5
Building improvements [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life, Minimum	3			3
Property, Plant and Equipment, Useful Life, Maximum	30			30

[1] Amounts as of July 31, 2011 are unaudited. Amounts as of October 31, 2010 are derived from the October 31, 2010 audited consolidated financial statements.