Borrowings (Details) - USD ($)	9 Months Ended	12 Months Ended
	Jul. 31, 2018	Oct. 31, 2017	Jun. 29, 2018
Long-term debt
Total long-term debt	$ 9,963,000,000	$ 10,182,000,000
Fair value adjustment related to hedged debt	(336,000,000)	(142,000,000)
Unamortized debt issuance costs	(40,000,000)	(47,000,000)
Less: current portion	(1,402,000,000)	(3,005,000,000)
$2,650 issued at discount to par at a price of 99.872% in October 2015 at 2.85%, due October 5, 2018, interest payable semi-annually on April 5 and October 5 of each year
Long-term debt
Total long-term debt	1,050,000,000	2,648,000,000
Face amount of debt instrument	$ 2,650,000,000	$ 2,650,000,000
Discount to par (as a percent)	99.872%	99.872%
Interest rate	2.85%	2.85%
Repurchased face amount of debt			$ 1,600,000,000
$250 issued at par in October 2015 at three-month USD LIBOR plus 1.93%, due October 5, 2018, interest payable quarterly on January 5, April 5, July 5 and October 5 of each year
Long-term debt
Face amount of debt instrument	$ 250,000,000	$ 250,000,000
$250 issued at par in October 2015 at three-month USD LIBOR plus 1.93%, due October 5, 2018, interest payable quarterly on January 5, April 5, July 5 and October 5 of each year | LIBOR
Long-term debt
Total long-term debt	$ 250,000,000	$ 250,000,000
Spread on reference interest rate (as a percent)	1.93%	1.93%
$1,100 issued at discount to par at a price of 99.994% in September 2017 at 2.10%, due October 4, 2019, interest payable semi-annually on April 4 and October 4 of each year
Long-term debt
Total long-term debt	$ 1,100,000,000	$ 1,100,000,000
Face amount of debt instrument	$ 1,100,000,000	$ 1,100,000,000
Discount to par (as a percent)	99.994%	99.994%
Interest rate	2.10%	2.10%
$3,000 issued at discount to par at a price of 99.972% in October 2015 at 3.6%, due October 15, 2020, interest payable semi-annually on April 15 and October 15 of each year
Long-term debt
Total long-term debt	$ 3,000,000,000	$ 3,000,000,000
Face amount of debt instrument	$ 3,000,000,000	$ 3,000,000,000
Discount to par (as a percent)	99.972%	99.972%
Interest rate	3.60%	3.60%
$1,350 issued at discount to par at a price of 99.802% in October 2015 at 4.4%, due October 15, 2022, interest payable semi-annually on April 15 and October 15 of each year
Long-term debt
Total long-term debt	$ 1,348,000,000	$ 1,348,000,000
Face amount of debt instrument	$ 1,350,000,000	$ 1,350,000,000
Discount to par (as a percent)	99.802%	99.802%
Interest rate	4.40%	4.40%
$2,500 issued at discount to par at a price of 99.725% in October 2015 at 4.9%, due October 15, 2025, interest payable semi-annually on April 15 and October 15 of each year
Long-term debt
Total long-term debt	$ 2,495,000,000	$ 2,495,000,000
Face amount of debt instrument	$ 2,500,000,000	$ 2,500,000,000
Discount to par (as a percent)	99.725%	99.725%
Interest rate	4.90%	4.90%
$750 issued at discount to par at a price of 99.942% in October 2015 at 6.2%, due October 15, 2035, interest payable semi-annually on April 15 and October 15 of each year
Long-term debt
Total long-term debt	$ 750,000,000	$ 750,000,000
Face amount of debt instrument	$ 750,000,000	$ 750,000,000
Discount to par (as a percent)	99.942%	99.942%
Interest rate	6.20%	6.20%
$1,500 issued at discount to par at a price of 99.932% in October 2015 at 6.35%, due October 15, 2045, interest payable semi-annually on April 15 and October 15 of each year
Long-term debt
Total long-term debt	$ 1,499,000,000	$ 1,499,000,000
Face amount of debt instrument	$ 1,500,000,000	$ 1,500,000,000
Discount to par (as a percent)	99.932%	99.932%
Interest rate	6.35%	6.35%
Other, including capital lease obligations, at 0.00%-6.05%, due in calendar years 2017-2030(2)
Long-term debt
Other, including capital lease obligations, at 0.00%-6.05%, due in calendar years 2017-2030(2)	$ 249,000,000	$ 286,000,000
Other, including capital lease obligations, at 0.00%-6.05%, due in calendar years 2017-2030(2) | Financial Services
Long-term debt
Other, including capital lease obligations	$ 143,000,000	$ 160,000,000
Other, including capital lease obligations, at 0.00%-6.05%, due in calendar years 2017-2030(2) | Minimum
Long-term debt
Interest rate	0.00%	0.00%
Other, including capital lease obligations, at 0.00%-6.05%, due in calendar years 2017-2030(2) | Maximum
Long-term debt
Interest rate	5.00%	5.00%