Retirement and Post-Retirement Benefit Plans (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended		12 Months Ended
		Apr. 30, 2017	Apr. 30, 2016	Apr. 30, 2017	Apr. 30, 2016	Oct. 31, 2016
Defined benefit plans
Pension expense adjustment		$ 46	$ 41	$ 111	$ 70
Defined benefit plan settlement charges and remeasurement benefit	[1]	16	0	21	0
Non-U.S. Defined Benefit Plans
Net benefit (credit) cost
Service cost		30	50	70	100
Interest cost		52	78	102	158
Expected return on plan assets		(131)	(161)	(264)	(331)
Amortization and deferrals:
Actuarial loss (gain)		64	54	140	109
Prior service benefit		(4)	(4)	(8)	(9)
Net periodic benefit cost		11	17	40	27
Settlement loss		3	1	3	1
Special termination benefits		1	1	2	3
Plan expense allocation		(5)	(2)	(15)	(4)
Net benefit cost from continuing operations		10	17	30	27
Discontinued operations		35	22	79	40
Net benefit cost		45	39	109	67
Employer Contributions and Funding Policy
Contributions to benefit plans				2,100
Expected contribution to defined benefit plans				299		$ 348
Expected additional contribution to benefit plans as a result of impact of foreign currency				79
United States Pension Plans Of U S Entity Nonqualified Plan Participants
Employer Contributions and Funding Policy
Expected contribution to defined benefit plans						2
Expected additional contribution to benefit plans as a result of impact of foreign currency				1
Post-Retirement Benefit Plans
Net benefit (credit) cost
Service cost		1	1	2	2
Interest cost		1	2	2	4
Expected return on plan assets		0	0	0	(1)
Amortization and deferrals:
Actuarial loss (gain)		(1)	(1)	(2)	(2)
Prior service benefit		0	0	0	0
Net periodic benefit cost		1	2	2	3
Settlement loss		0	0	0	0
Special termination benefits		0	0	0	0
Plan expense allocation		0	0	(1)	0
Net benefit cost from continuing operations		1	2	1	3
Discontinued operations		0	0	1	0
Net benefit cost		1	$ 2	2	$ 3
Employer Contributions and Funding Policy
Expected contribution to defined benefit plans				1		$ 3
Expected additional contribution to benefit plans as a result of impact of foreign currency				2
Disposal Group, Disposed of by Means Other than Sale, Not Discontinued Operations, Spinoff
Defined benefit plans
Pension expense adjustment		23
Disposal Group, Disposed of by Means Other than Sale, Not Discontinued Operations, Spinoff | Non-U.S. Defined Benefit Plans
Employer Contributions and Funding Policy
Contributions to benefit plans				$ 1,900
Net earnings (loss) from continuing operations
Defined benefit plans
Defined benefit plan settlement charges and remeasurement benefit	[1]	16
Income From Continuing Operations
Defined benefit plans
Defined benefit plan settlement charges and remeasurement benefit	[1]	$ 17

[1] Represents adjustments to the net periodic pension cost resulting from remeasurements of certain Hewlett Packard Enterprise pension plans due to plan separations in connection with the spin-off and merger of Everett SpinCo, Inc. with Computer Sciences Corporation.