Financial Instruments - Schedule of Cash Equivalents and Available-for-Sale Investments (Details) - USD ($) $ in Millions	Jul. 31, 2017	Oct. 31, 2016
Cash Equivalents:
Cost	$ 5,416	$ 4,660
Fair Value	5,416	4,660
Available-for-Sale Investments:
Cost	1,060	38
Gross Unrealized Gain	17	12
Gross Unrealized Loss	0	0
Fair Value	1,077	50
Total cash equivalents and available-for-sale investments, Cost	6,476	4,698
Total cash equivalents and available-for-sale investments, Fair Value	6,493	4,710
Corporate debt
Cash Equivalents:
Cost	1,929	2,092
Fair Value	1,929	2,092
Available-for-Sale Investments:
Cost	506	0
Gross Unrealized Gain	0	0
Gross Unrealized Loss	0	0
Fair Value	506	0
Financial institution instruments
Cash Equivalents:
Cost	5	0
Fair Value	5	0
Available-for-Sale Investments:
Cost	50	2
Gross Unrealized Gain	0	0
Gross Unrealized Loss	0	0
Fair Value	50	2
Government debt
Cash Equivalents:
Cost	3,482	2,568
Fair Value	3,482	2,568
Available-for-Sale Investments:
Cost	464	0
Gross Unrealized Gain	0	0
Gross Unrealized Loss	0	0
Fair Value	464	0
Marketable equity securities
Available-for-Sale Investments:
Cost	1	1
Gross Unrealized Gain	7	3
Gross Unrealized Loss	0	0
Fair Value	8	4
Mutual funds
Available-for-Sale Investments:
Cost	39	35
Gross Unrealized Gain	10	9
Gross Unrealized Loss	0	0
Fair Value	$ 49	$ 44