Financing Receivables and Operating Leases - Aging and Allowance (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Jul. 31, 2016	Oct. 31, 2015	Jul. 31, 2016	Oct. 31, 2015
Gross financing receivables
Period past due, after which a write-off or specific reserve is created	180 days
Allowance for doubtful accounts
Balance at beginning of period	$ 95	$ 111
Provision for doubtful accounts	3	25
Write-offs	(9)	(41)
Balance at end of period	89	95
Gross financing receivables collectively evaluated for loss			$ 6,668	$ 6,399
Gross financing receivables individually evaluated for loss			237	256
Financing receivables, gross			6,905	6,655
Allowance for financing receivables collectively evaluated for loss			74	82
Allowance for financing receivables individually evaluated for loss			15	13
Total	$ 95	$ 111	89	95
Period past due, after which account is put on non-accrual status	90 days
Aging and non-accrual status of gross financing receivables
Current 1-30 days			343	358
Past due 31-60 days			49	52
Past due 61-90 days			14	14
Past due 90 days			63	57
Unbilled sales-type and direct-financing lease receivables			6,436	6,174
Gross financing receivables on non-accrual status			147	154
Gross financing receivables 90 days past due and still accruing interest			90	102
Operating lease assets
Equipment leased to customers			5,340	4,428
Accumulated depreciation			(2,109)	(1,513)
Operating lease assets, net			3,231	2,915
Low
Allowance for doubtful accounts
Financing receivables, gross			3,461	3,467
Moderate
Allowance for doubtful accounts
Financing receivables, gross			3,366	3,115
High
Allowance for doubtful accounts
Financing receivables, gross			$ 78	$ 73