Financial Instruments - Schedule of Cash Equivalents and Available-for-Sale Investments (Details) - USD ($) $ in Millions	Jul. 31, 2019	Oct. 31, 2018
Cash Equivalents:
Cost	$ 4,117	$ 3,996
Fair Value	4,117	3,996
Available-for-Sale Investments:
Debt Securities, Trading, and Equity Securities, FV-NI, Cost	42	756
Debt Securities, Trading, and Equity Securities, FV-NI, Accumulated Gross Unrealized Gain, before Tax	13	11
Debt Securities, Trading, and Equity Securities, FV-NI, Accumulated Gross Unrealized Loss, before Tax	0	(3)
Debt Securities, Trading, and Equity Securities, FV-NI	55	764
Total cash equivalents and available-for-sale investments, Cost	4,159	4,752
Cash Equivalents and Available For Sale Securities, Accumulated Gross Unrealized Gain, before Tax	13	11
Cash Equivalents and Available For Sale Securities, Accumulated Gross Unrealized Loss, before Tax	0	(3)
Total cash equivalents and available-for-sale investments, Fair Value	4,172	4,760
Corporate debt
Cash Equivalents:
Cost	1,188	1,620
Fair Value	1,188	1,620
Available-for-Sale Investments:
Debt Securities, Available-for-sale, Amortized Cost	0	368
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	0	(2)
Debt Securities, Available-for-sale	0	366
Financial institution instruments
Cash Equivalents:
Cost	0	9
Fair Value	0	9
Available-for-Sale Investments:
Debt Securities, Available-for-sale, Amortized Cost	0	32
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	0	0
Debt Securities, Available-for-sale	0	32
Government debt
Cash Equivalents:
Cost	2,929	2,367
Fair Value	2,929	2,367
Available-for-Sale Investments:
Debt Securities, Available-for-sale, Amortized Cost	0	314
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	0	(1)
Debt Securities, Available-for-sale	0	313
Marketable equity securities
Available-for-Sale Investments:
Equity Securities, FV-NI, Cost	4	4
Equity Securities, FV-NI, Accumulated Gross Unrealized Gain, before Tax	2	2
Equity Securities, FV-NI, Accumulated Gross Unrealized Loss, before Tax	0	0
Equity Securities, FV-NI	6	6
Mutual funds
Available-for-Sale Investments:
Debt Securities, Available-for-sale, Amortized Cost	38	38
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	11	9
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	0	0
Debt Securities, Available-for-sale	$ 49	$ 47