Income Taxes - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Oct. 31, 2014	Apr. 30, 2014	Oct. 31, 2015	Oct. 31, 2014	Oct. 31, 2013
Operating Loss Carryforwards [Line Items]
Income Tax Expense (Benefit)			$ 51	$ 26	$ (171)
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount	$ (16)	$ 29	41	234	350
Deferred Tax Assets, Valuation Allowance	3,174		3,260	3,174
Undistributed Earnings of Foreign Subsidiaries			565
Deferred tax liabilities related to unremitted foreign earnings	6		37	6
Deferred Tax Assets, Operating Loss Carryforwards, Domestic			840
Deferred Tax Assets, Operating Loss Carryforwards, State and Local			145
Deferred Tax Assets, Operating Loss Carryforwards, Foreign			176
Deferred Tax Assets, Operating Loss Carryforwards	1,213		$ 1,161	1,213
Income Taxes Percent Likelihood Of Being Realized Upon Settlement			50.00%
Unrecognized Tax Benefits	47		$ 41	47
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense			(1)	4	(6)
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued	$ 8		8	$ 8
Intraperiod Tax Allocation Rule [Member]
Operating Loss Carryforwards [Line Items]
Income Tax Expense (Benefit)					(220)
Other Comprehensive Income (Loss) [Member]
Operating Loss Carryforwards [Line Items]
Income Tax Expense (Benefit)			$ (14)		(212)
Additional Paid-in Capital [Member]
Operating Loss Carryforwards [Line Items]
Income Tax Expense (Benefit)					$ (8)
Convertible Subordinated Debt [Member]
Operating Loss Carryforwards [Line Items]
Income Tax Expense (Benefit)		$ (13)
Maximum [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards, Duration of Carryforward			20 years
Minimum [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards, Duration of Carryforward			5 years
Stock Option Tax Benefits [Member]
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Operating Loss Carryforwards			$ 63