Stock-Based Compensation (Details) (USD $)	12 Months Ended			1 Months Ended						12 Months Ended
	Oct. 31, 2011	Oct. 31, 2010	Oct. 31, 2009	Nov. 30, 2010 HP plans	Nov. 30, 2009 HP plans	Oct. 31, 2011 HP plans	Oct. 31, 2010 HP plans	Oct. 31, 2009 HP plans	Oct. 31, 2009 Assumed Compaq and EDS plans	Oct. 31, 2011 Cash-settled awards and restricted stock awards	Oct. 31, 2011 Performance-based Restricted Units (PRUs) M Year	Oct. 31, 2010 Performance-based Restricted Units (PRUs) M Year	Oct. 31, 2009 Performance-based Restricted Units (PRUs) Year M	Oct. 31, 2011 Stock Options Year M EmployeePopulations	Oct. 31, 2010 Stock Options Year M	Oct. 31, 2009 Stock Options M	Oct. 31, 2011 Restricted Stock Awards Year	Oct. 31, 2010 Restricted Stock Awards Year	Oct. 31, 2011 Restricted stock	Oct. 31, 2010 Restricted stock	Oct. 31, 2011 Restricted stock units	Oct. 31, 2010 Restricted stock units
Stock Based Compensation Expense
Stock-based compensation expense	$ 685,000,000	$ 668,000,000	$ 635,000,000
Income tax benefit from stock-based compensation	219,000,000	216,000,000	199,000,000
Cash received from option exercises and purchases under the ESPP	896,000,000	2,617,000,000	1,837,000,000
Actual tax benefit realized for the tax deduction from option exercises of the share-based payment awards	220,000,000	414,000,000	252,000,000
Share-based compensation arrangements by share-based payment award
Unrecognized pre-tax stock-based compensation expense											82,000,000	222,000,000		264,000,000	280,000,000		526,000,000	152,000,000
Remaining weighted-average vesting period (in years)											1.4	1.2		2.3	1.6		1.4	1.5
Performance-based Restricted Units
Performance period to determine share based awards (in years)											3	3	3
Percentage of performance target, low end of range (as a percent)											0.00%
Percentage of performance target, high end of range (as a percent)											200.00%
Shares credited if cash flow performance is below the minimum level (as a percent)											0.00%
Shares credited if cash flow performance is at or above the maximum level (as a percent)											150.00%
Shares credited for cash flow performance between the minimum level and the maximum level, low end of range (as a percent)											30.00%
TSR modifier, if the minimum level is not met (as a percent)											0.00%
TSR modifier, if performance is at or above the maximum level (as a percent)											133.00%
TSR modifier, for performance between the minimum level and the maximum level, low end of range (as a percent)											66.00%
Stock Options
Contractual term of options granted since 2003 (in years)														8
Contractual term of options granted prior to 2003 (in years)														10
Discount to fair market value which may be applied to exercise price (as a percent)														75.00%
Number of employee populations used to apply Black-Scholes model														3
Vesting Period
Vesting period, low end of range (in years)										1Y				3Y
Vesting period, high end of range (in years)										3Y				4Y
Weighted average assumptions used to determine fair values
Weighted average fair value of grants per share (in dollars per share)														$ 7.85	$ 13.33	$ 13.04
Expected or implied volatility (as a percent)											30.00%	38.00%	35.00%	41.00%	30.00%	43.00%
Risk-free interest rate (as a percent)											0.38%	0.73%	1.34%	1.20%	2.06%	2.07%
Dividend yield (as a percent)											0.75%	0.64%	0.88%	1.97%	0.68%	0.92%
Expected life (in months)											19	22	30	63	61	61
Activity
Outstanding at the beginning of the period (in shares)											18,508,000	21,093,000					5,848,000	6,864,000	1,936,000		3,912,000
Granted and assumed through acquisition (in shares)																	17,569,000	4,821,000	335,000	1,543,000	17,234,000	3,278,000
Granted (in shares)											5,950,000	7,388,000
Vested (in shares)											0	(7,186,000)					(5,660,000)	(5,202,000)
Change in units due to performance and market conditions achievement for PRUs vested in the year (in shares)											(10,862,000)	(108,000)
Forfeited (in shares)											(2,214,000)	(2,679,000)					(944,000)	(635,000)
Outstanding at the end of the period (in shares)											11,382,000	18,508,000	21,093,000				16,813,000	5,848,000	984,000	1,936,000	15,829,000	3,912,000
Outstanding Target shares assigned a fair value (in shares)											5,867,000	10,201,000
Weighted-average grant date fair value, beginning of period (in dollars per share)																	$ 45	$ 44
Weighted-average grant date fair value of shares granted (in dollars per share)											$ 27.59	$ 57.13	$ 40.56
Weighted-average grant date fair value of shares granted and assumed through acquisition (in dollars per share)																	$ 38	$ 48	$ 42	$ 48	$ 38	$ 48
Weighted-average grant date fair value of shares vested (in dollars per share)																	$ 41	$ 46
Weighted-average grant date fair value of shares forfeited (in dollars per share)																	$ 43	$ 46
Weighted-average grant date fair value, end of period (in dollars per share)																	$ 39	$ 45
Restricted stock units assumed through acquisitions (in shares)																					0	3,000,000
Weighted-average grant date fair value of restricted stock units assumed through acquisitions (in dollars per share)																					$ 0	$ 48
Option activity:
Outstanding at the beginning of the period (in shares)														142,916,000	233,214,000
Granted and assumed through acquisition (in shares)														18,804,000	11,939,000
Exercised (in shares)														(37,121,000)	(75,002,000)
Forfeited/cancelled/expired (in shares)														(4,356,000)	(27,235,000)
Outstanding at the end of the period (in shares)														120,243,000	142,916,000	233,214,000
Weighted-average exercise price of shares outstanding, at the beginning of the period (in dollars per share)														$ 28	$ 33
Weighted-average exercise price of shares granted or assumed through acquisition (in dollars per share)														$ 21	$ 22
Weighted-average exercise price of shares exercised (in dollars per share)														$ 23	$ 34
Weighted-average exercise price of shares forfeited, cancelled or expired (in dollars per share)														$ 39	$ 55
Weighted-average exercise price of shares outstanding, at the end of the period (in dollars per share)														$ 28	$ 28	$ 33
Weighted-average remaining contractual term of shares outstanding (in years)														3.0	2.7
Aggregate intrinsic value of shares outstanding														460,000,000	2,140,000,000
Shares vested and expected to vest (in shares)														117,066,000	141,082,000
Weighted-average exercise price of shares vested and expected to vest (in dollars per share)														$ 28	$ 28
Weighted-average remaining contractual term of shares vested and expected to vest (in years)														2.9	2.7
Aggregate intrinsic value of shares vested and expected to vest														442,000,000	2,114,000,000
Shares exercisable (in shares)														97,967,000	125,232,000
Weighted-average exercise price of exercisable options (in dollars per share)														$ 29	$ 28
Weighted-average remaining contractual term of exercisable options (in years)														2.0	2.1
Aggregate intrinsic value of exercisable options														332,000,000	1,895,000,000
Shares assumed through acquisitions (in shares)														6,000,000	10,000,000
Weighted-average exercise price of options assumed through acquisitions (in dollars per share)														$ 14	$ 19
Aggregate intrinsic value of options exercised														700,000,000	1,300,000,000	800,000,000
Total grant date fair value of options vested and expensed														$ 95,000,000	$ 93,000,000	$ 172,000,000
Shares reserved
Shares available for future grant at October 31 (in shares)	172,259,000	124,553,000	177,760,000			172,259,000	124,533,000	95,311,000	82,449,000
Shares reserved for future issuance under all stock related benefit plans at October 31 (in shares)	319,602,000	296,973,000	410,977,000
Number of shares available for future grant that expired (in shares)				30,000,000	24,000,000