Financial Instruments - Schedule of Cash Equivalents and Available-for-Sale Investments (Details) - USD ($) $ in Millions	Apr. 30, 2020	Oct. 31, 2019
Cash Equivalents:
Cost	$ 2,829	$ 3,705
Gross Unrealized Gain	0	0
Gross Unrealized Loss	0	0
Fair Value	2,829	3,705
Available-for-Sale Investments:
Equity securities, Cost	39	40
Equity securities, Gross Unrealized Gain	13	16
Equity securities, Gross Unrealized Loss	0	0
Equity securities, Fair Value	52	56
Total cash equivalents and available-for-sale investments, Cost	2,868	3,745
Total cash equivalents and available-for-sale investments, Gross Unrealized Gain	13	16
Total cash equivalents and available-for-sale investments, Gross Unrealized Loss	0	0
Total cash equivalents and available-for-sale investments, Fair Value	2,881	3,761
Corporate debt
Cash Equivalents:
Cost	622	1,283
Gross Unrealized Gain	0	0
Gross Unrealized Loss	0	0
Fair Value	622	1,283
Government debt
Cash Equivalents:
Cost	2,207	2,422
Gross Unrealized Gain	0	0
Gross Unrealized Loss	0	0
Fair Value	2,207	2,422
Marketable equity securities and Mutual funds
Available-for-Sale Investments:
Equity securities, Cost	39	40
Equity securities, Gross Unrealized Gain	13	16
Equity securities, Gross Unrealized Loss	0	0
Equity securities, Fair Value	$ 52	$ 56