Financing Receivables and Operating Leases - Aging and Allowance (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Apr. 30, 2017	Oct. 31, 2016	Apr. 30, 2017	Oct. 31, 2016
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	$ 89	$ 95
Provision for doubtful accounts	8	11
Write-offs	(17)	(17)
Balance at end of period	80	89
Gross financing receivables collectively evaluated for loss			$ 6,974	$ 7,750
Gross financing receivables individually evaluated for loss			288	283
Financing receivables, gross			7,262	8,033
Allowance for financing receivables collectively evaluated for loss			62	73
Allowance for financing receivables individually evaluated for loss			18	16
Total	$ 89	$ 95	80	89
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			311	389
Past due 31-60 days			34	54
Past due 61-90 days			36	14
Past due 90 days			55	68
Unbilled sales-type and direct-financing lease receivables			6,826	7,508
Gross financing receivables on non-accrual status			181	163
Gross financing receivables 90 days past due and still accruing interest			107	120
Operating lease assets
Equipment leased to customers			7,593	5,467
Accumulated depreciation			(2,900)	(2,134)
Operating lease assets, net			4,693	3,333
Low
Allowance for doubtful accounts
Financing receivables, gross			3,826	4,027
Moderate
Allowance for doubtful accounts
Financing receivables, gross			3,337	3,909
High
Allowance for doubtful accounts
Financing receivables, gross			$ 99	$ 97