Stock-Based Compensation (Detail) - USD ($)				3 Months Ended								12 Months Ended
	Apr. 01, 2017	Jan. 25, 2017	Nov. 01, 2015	Oct. 31, 2018	Jul. 31, 2018	Apr. 30, 2018	Jan. 31, 2018	Oct. 31, 2017	Jul. 31, 2017	Apr. 30, 2017	Jan. 31, 2017	Oct. 31, 2018	Oct. 31, 2017	Oct. 31, 2016
Stock-Based Compensation
Stock-based compensation expense												$ 309,000,000	$ 454,000,000	$ 408,000,000
Income tax benefit												(56,000,000)	(159,000,000)	(131,000,000)
Stock-based compensation expense, net of tax												253,000,000	295,000,000	277,000,000
Separation costs				$ 12,000,000	$ (2,000,000)	$ 26,000,000	$ (24,000,000)	$ 202,000,000	$ 5,000,000	$ 30,000,000	$ 11,000,000	12,000,000	248,000,000	362,000,000
Restructuring charges				5,000,000	$ 2,000,000	$ 9,000,000	$ 3,000,000	$ 113,000,000	$ 152,000,000	$ 69,000,000	$ 83,000,000	$ 19,000,000	$ 417,000,000	417,000,000
Increased expense due to the acceleration														33,000,000
Shares
Outstanding at end of period (in shares)							49,274,000					49,274,000
Outstanding at end of period (in shares)								49,274,000					49,274,000
Weighted- Average Exercise Price
Outstanding at beginning of period (in dollars per share)							$ 10					$ 10
Outstanding at end of period (in dollars per share)								$ 10					$ 10
Aggregate Intrinsic Value
Number of options assumed (in shares)													8,000,000
Weighted-average exercise price of options assumed (in dollars per share)													$ 16
Employee Stock Purchase Plan
Stock-Based Compensation
Stock-based compensation expense, net of tax												$ 0
Corporate and unallocated assets | HP Inc.
Stock-Based Compensation
Stock-based compensation expense														$ 8,000,000
Restricted Stock Awards
Shares
Outstanding at beginning of period (in shares)							48,517,000				57,321,000	48,517,000	57,321,000
Converted from former Parent's plan (in shares)													0
Granted and assumed through acquisition (in shares)													23,980,000
Additional shares granted due to conversion (shares)													25,543,000
Vested (in shares)													(51,976,000)
Forfeited (in shares)													(6,351,000)
Outstanding at end of period (in shares)								48,517,000					48,517,000	57,321,000
Weighted- Average Grant Date Fair Value Per Share
Outstanding at beginning of period (in dollars per share)							$ 14				$ 15	$ 14	$ 15
Converted from former Parent's plan (in dollars per share)													0
Granted and assumed through acquisition (in dollars per share)													21
Additional shares granted due to conversion (in dollars per share)													9
Vested (in dollars per share)													16
Forfeited (in dollars per share)													16
Outstanding at end of period (in dollars per share)								$ 14					$ 14	$ 15
Total grant date fair value of restricted stock vested												$ 270,000,000	$ 472,000,000	$ 130,000,000
Unrecognized pre-tax stock-based compensation expense and recognition period
Unrecognized pre-tax stock-based compensation expense				259,000,000								$ 259,000,000
Remaining weighted-average vesting period over which pre-tax stock-based compensation expense is expected to be recognized												1 year 4 months 24 days
The Plan
Stock-Based Compensation
Number of shares authorized and available for issuance (shares)		210,000,000	260,000,000
Number of additional shares authorized	67,000,000
Vesting period		3 years
Stock Options
Unrecognized pre-tax stock-based compensation expense and recognition period
Unrecognized pre-tax stock-based compensation expense				$ 7,000,000								$ 7,000,000
Remaining weighted-average vesting period over which pre-tax stock-based compensation expense is expected to be recognized												1 year 3 months 18 days
Weighted-average fair value and the assumptions used to measure fair value
Weighted- average fair value of grants per option (in dollars per share)													$ 6	$ 4
Expected volatility (as a percent)													25.70%	31.10%
Risk-free interest rate (as a percent)													2.00%	1.70%
Expected dividend yield (as a percent)													1.00%	1.50%
Expected term in years													6 years 1 month 6 days	5 years 4 months 12 days
Shares
Outstanding at end of period (in shares)							49,274,000				57,498,000	49,274,000	57,498,000
Converted from former Parent's plan (in shares)												0	0
Granted and assumed through acquisitions (in shares)												316,000	6,074,000
Additional shares granted due to post-spin adjustments (in shares)												0	24,523,000
Exercised (in shares)												(26,476,000)	(29,492,000)
Forfeited/cancelled/expired (in shares)												(4,851,000)	(9,329,000)
Outstanding at end of period (in shares)				18,263,000				49,274,000				18,263,000	49,274,000	57,498,000
Vested and expected to vest at end of period (in shares)				18,038,000				48,566,000				18,038,000	48,566,000
Exercisable at end of period (in shares)				14,896,000				24,736,000				14,896,000	24,736,000
Weighted- Average Exercise Price
Outstanding at beginning of period (in dollars per share)							$ 10				$ 15	$ 10	$ 15
Converted from former Parent's plan (in dollars per share)												0	0
Granted and assumed through acquisition (in dollars per share)												10	23
Additional shares granted due to post-spin adjustments (in dollars per share)												0	11
Exercised (in dollars per share)												9	12
Forfeited/cancelled/expired (in dollars per share)												13	16
Outstanding at end of period (in dollars per share)				$ 10				$ 10				10	10	$ 15
Vested and expected to vest at end of period (in dollars per share)				10				10				10	10
Exercisable at end of period (in dollars per share)				$ 10				$ 9				$ 10	$ 9
Weighted- Average Remaining Contractual Term
Outstanding at end of year(4)												4 years 2 months 12 days	4 years 7 months 6 days
Vested and expected to vest at end of year(4)												4 years 2 months 12 days	4 years 7 months 6 days
Exercisable at end of year(4)												3 years 8 months 12 days	3 years
Aggregate Intrinsic Value
Outstanding at end of year(4)				$ 92,000,000				$ 207,000,000				$ 92,000,000	$ 207,000,000
Vested and expected to vest at end of year(4)				91,000,000				205,000,000				91,000,000	205,000,000
Exercisable at end of year(4)				$ 85,000,000				$ 123,000,000				85,000,000	123,000,000
Options exercised												$ 200,000,000	$ 218,000,000	$ 62,000,000
The Plan | Restricted Stock Awards
Shares
Outstanding at beginning of period (in shares)							48,517,000					48,517,000
Converted from former Parent's plan (in shares)												0
Granted and assumed through acquisition (in shares)												22,131,000
Additional shares granted due to conversion (shares)												0
Vested (in shares)												(32,659,000)
Forfeited (in shares)												(5,572,000)
Outstanding at end of period (in shares)				32,417,000				48,517,000				32,417,000	48,517,000
Weighted- Average Grant Date Fair Value Per Share
Outstanding at beginning of period (in dollars per share)							$ 14					$ 14
Converted from former Parent's plan (in dollars per share)												0
Granted and assumed through acquisition (in dollars per share)												15
Additional shares granted due to conversion (in dollars per share)												0
Vested (in dollars per share)												14
Forfeited (in dollars per share)												14
Outstanding at end of period (in dollars per share)				$ 14				$ 14				$ 14	$ 14
One Time Retention Stock Awards | Restricted Stock Awards
Shares
Granted and assumed through acquisition (in shares)														5,000,000
One Time Retention Stock Awards | The Plan
Stock-Based Compensation
Vesting period			3 years
Total grant date fair value of options vested			$ 137,000,000
One Time Retention Stock Awards | Stock Options
Shares
Granted and assumed through acquisitions (in shares)														16,000,000
The Plan
Stock-Based Compensation
Separation costs												$ 10,000,000	$ 41,000,000
Restructuring charges												3,000,000	$ 33,000,000
Former Parent Company | Restricted Stock Awards
Shares
Outstanding at beginning of period (in shares)			0								57,321,000		57,321,000	0
Converted from former Parent's plan (in shares)														42,012,000
Granted and assumed through acquisition (in shares)														32,752,000
Additional shares granted due to conversion (shares)														0
Vested (in shares)														(12,747,000)
Forfeited (in shares)														(4,696,000)
Outstanding at end of period (in shares)														57,321,000
Weighted- Average Grant Date Fair Value Per Share
Outstanding at beginning of period (in dollars per share)			$ 0								$ 15		$ 15	$ 0
Converted from former Parent's plan (in dollars per share)														15
Granted and assumed through acquisition (in dollars per share)														15
Additional shares granted due to conversion (in dollars per share)														0
Vested (in dollars per share)														15
Forfeited (in dollars per share)														15
Outstanding at end of period (in dollars per share)														$ 15
Former Parent Company | Stock Options
Shares
Outstanding at end of period (in shares)			0								57,498,000		57,498,000	0
Converted from former Parent's plan (in shares)														42,579,000
Granted and assumed through acquisitions (in shares)														25,390,000
Additional shares granted due to post-spin adjustments (in shares)														0
Exercised (in shares)														(7,845,000)
Forfeited/cancelled/expired (in shares)														(2,626,000)
Outstanding at end of period (in shares)														57,498,000
Vested and expected to vest at end of period (in shares)														55,716,000
Exercisable at end of period (in shares)														26,204,000
Weighted- Average Exercise Price
Outstanding at beginning of period (in dollars per share)			$ 0								$ 15		$ 15	$ 0
Converted from former Parent's plan (in dollars per share)														15
Granted and assumed through acquisition (in dollars per share)														15
Additional shares granted due to post-spin adjustments (in dollars per share)														0
Exercised (in dollars per share)														11
Forfeited/cancelled/expired (in dollars per share)														20
Outstanding at end of period (in dollars per share)														15
Vested and expected to vest at end of period (in dollars per share)														15
Exercisable at end of period (in dollars per share)														$ 13
Weighted- Average Remaining Contractual Term
Outstanding at end of year(4)														5 years 4 months 24 days
Vested and expected to vest at end of year(4)														5 years 3 months 18 days
Exercisable at end of year(4)														3 years 9 months 18 days
Aggregate Intrinsic Value
Outstanding at end of year(4)														$ 437,000,000
Vested and expected to vest at end of year(4)														425,000,000
Exercisable at end of year(4)														241,000,000
Discontinued Operations
Stock-Based Compensation
Stock-based compensation expense												0	$ 166,000,000	189,000,000
Restructuring charges													251,000,000	$ 819,000,000
SGI And Nimble Storage | The Plan
Stock-Based Compensation
Restructuring charges												$ 10,000,000	$ 23,000,000
2017 Acquisitions | Restricted Stock Awards
Weighted- Average Grant Date Fair Value Per Share
Shares assumed in period (in shares)													11,000,000
Granted (in dollars per share)													$ 18
Everett and Seattle Transactions | Restricted Stock Awards
Shares
Vested (in shares)													(14,000,000)
Forfeited (in shares)													(300,000)
Weighted- Average Grant Date Fair Value Per Share
Vested (in dollars per share)													$ 17
Forfeited (in dollars per share)													$ 18
Everett Transaction | Restricted Stock Awards
Shares
Vested (in shares)												(6,000,000)
Weighted- Average Grant Date Fair Value Per Share
Vested (in dollars per share)												$ 14
Everett Transaction | The Plan
Stock-Based Compensation
Separation costs													$ 126,000,000
Restructuring charges													34,000,000
Everett Transaction | Net Income (Loss) | Discontinued Operations
Stock-Based Compensation
Stock-based compensation expense													$ 92,000,000