Income Taxes - Narrative (Details) - USD ($)	3 Months Ended
	Jan. 31, 2018	Jan. 31, 2017
Operating Loss Carryforwards [Line Items]
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount	$ 0.21	$ 0.35
Deferred Tax Assets, Valuation Allowance	$ 1,000,000,000
Income Taxes Percent Likelihood Of Being Realized Upon Settlement	50.00%
Income tax expense	$ (15,000,000)	$ (4,000,000)
Unrecognized Tax Benefits	$ 31,000,000
Interest and Penalties from Uncertain Tax Positions, Income Tax Expense	less than $1 million
Other Comprehensive Income (Loss) [Member]
Operating Loss Carryforwards [Line Items]
Income tax expense	$ 10,000,000