Acquisitions, Goodwill and Intangible Assets (Details) (USD $)	12 Months Ended			3 Months Ended
	Oct. 31, 2014 item	Oct. 31, 2013	Oct. 31, 2012	Jan. 31, 2014	Aug. 01, 2014	Aug. 01, 2012
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Goodwill	$ 31,139,000,000	$ 31,124,000,000	$ 31,069,000,000
Goodwill
Balance at the beginning of year	31,124,000,000	31,069,000,000		31,124,000,000
Goodwill acquired during the period	12,000,000	112,000,000
Goodwill adjustments	3,000,000	(57,000,000)
Balance at the end of year	31,139,000,000	31,124,000,000	31,069,000,000
Finite-lived Intangible Assets, Accumulated Impairment Losses			(4,300,000,000)
Impairment loss	0	0	5,700,000,000
Accumulated impairment loss	14,500,000,000
Impairment of goodwill and intangible assets			18,035,000,000
Number of new reportable units	2
Acquisitions
Goodwill
Number of acquisitions	2
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Total purchase price	55,000,000
Goodwill	12,000,000
Intangible assets	25,000,000
Goodwill
Balance at the end of year	12,000,000
Digital Risk LLC | MphasiS
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Total purchase price		174,000,000
Goodwill		112,000,000
Intangible assets		48,000,000
Goodwill
Balance at the end of year		112,000,000
Autonomy
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Goodwill			1,200,000,000
Goodwill
Balance at the end of year			1,200,000,000
Finite-lived Intangible Assets, Accumulated Impairment Losses			(3,100,000,000)
Impairment of goodwill and intangible assets			8,800,000,000
Personal Systems
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Goodwill	2,588,000,000	2,588,000,000	2,588,000,000
Goodwill
Balance at the end of year	2,588,000,000	2,588,000,000	2,588,000,000
Printing
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Goodwill	2,591,000,000	2,591,000,000	2,591,000,000
Goodwill
Balance at the end of year	2,591,000,000	2,591,000,000	2,591,000,000
Enterprise Group
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Goodwill	16,867,000,000	16,864,000,000
Goodwill
Balance at the beginning of year	16,864,000,000	16,825,000,000		16,864,000,000
Goodwill adjustments	3,000,000	39,000,000
Balance at the end of year	16,867,000,000	16,864,000,000
Enterprise Services segment
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Goodwill	97,000,000	97,000,000
Goodwill
Goodwill acquired during the period		112,000,000
Goodwill adjustments		(15,000,000)
Balance at the end of year	97,000,000	97,000,000
Accumulated impairment loss	8,000,000,000		0
Software
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Goodwill	8,852,000,000	8,840,000,000	8,921,000,000
Goodwill
Balance at the beginning of year	8,840,000,000	8,921,000,000		8,840,000,000
Goodwill acquired during the period	12,000,000
Goodwill adjustments		(81,000,000)
Balance at the end of year	8,852,000,000	8,840,000,000	8,921,000,000
Accumulated impairment loss	5,700,000,000
Goodwill transferred				22,000,000
Number of reporting units within Software segment			2
Software | Autonomy Goodwill and Intangibles
Goodwill
Impairment of goodwill and intangible assets			8,800,000,000
HP Financial Services
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Goodwill	144,000,000	144,000,000	144,000,000
Goodwill
Balance at the end of year	144,000,000	144,000,000	144,000,000
Corporate Investments | Autonomy
Goodwill
Accumulated impairment loss			800,000,000
Other reporting units
Goodwill
Accumulated impairment loss					0	0
Printing Spare And Replacement Parts [Member] | Printing
Goodwill
Goodwill transferred				126,000,000
Personal Systems Spare And Replacement Parts [Member] | Personal Systems
Goodwill
Goodwill transferred				48,000,000
Personal Systems Trade And Warranty Support [Member] | Personal Systems
Goodwill
Goodwill transferred				$ 42,000,000