Income Taxes - Narrative (Details) - USD ($) $ in Millions	3 Months Ended			6 Months Ended
	Apr. 30, 2016	Jan. 31, 2016	Apr. 30, 2015	Apr. 30, 2016	Apr. 30, 2015
Operating Loss Carryforwards [Line Items]
Income Tax Expense (Benefit)	$ 16		$ 18	$ 11	$ 25
Income Taxes Percent Likelihood Of Being Realized Upon Settlement	50.00%			50.00%
Unrecognized Tax Benefits	$ 42			$ 42
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense	1			$ 1
Other Comprehensive Income (Loss) [Member]
Operating Loss Carryforwards [Line Items]
Income Tax Expense (Benefit)	$ (12)
Alternative Minimum Tax [Member]
Operating Loss Carryforwards [Line Items]
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount		$ 13