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Debt - Schedule of Debt Instruments (Details) - USD ($) $ in Millions	Jan. 31, 2020	Oct. 31, 2019	Jul. 31, 2019
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.625%
Long-term Debt and Capital Lease Obligations	$ 4,283	$ 4,317
Financial Services Operations
Debt Instrument [Line Items]
Long-term Debt and Capital Lease Obligations, Including Current Maturities		2,256	$ 1,814
Long-term Debt and Capital Lease Obligations, Current		839	421
Long-term Debt and Capital Lease Obligations		1,417	1,393
Financial Services Operations \| Secured Debt [Member]
Debt Instrument [Line Items]
Long-term Debt		991	673
Debt Issuance Costs, Net	3	4
Financial Services Operations \| Line of Credit [Member]
Debt Instrument [Line Items]
Long-term Debt		1,059	978
Debt Issuance Costs, Net	1	1
Financial Services Operations \| Commercial Paper [Member]
Debt Instrument [Line Items]
Long-term Debt		84
Commercial Paper			44
Financial Services Operations \| Borrowings Secured By Operating and Finance Leases [Member]
Debt Instrument [Line Items]
Long-term Debt		122	119
Manufacturing Operations [Member]
Debt Instrument [Line Items]
Long-term Debt and Capital Lease Obligations, Including Current Maturities		2,932	2,921
Long-term Debt and Capital Lease Obligations, Current		32	31
Long-term Debt and Capital Lease Obligations		2,900	2,890
Manufacturing Operations [Member] \| Line of Credit [Member]
Debt Instrument [Line Items]
Debt Instrument, Unamortized Discount	6	6
Long-term Debt		1,556	1,553
Debt Issuance Costs, Net	$ 9	10
Manufacturing Operations [Member] \| Notes Payable to Banks [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6750000.00%
Manufacturing Operations [Member] \| Notes Payable to Banks [Member] \| Six Point Six Two Five Percent Senior Notes [Member]
Debt Instrument [Line Items]
Long-term Debt		1,085	$ 1,086
Debt Issuance Costs, Net	$ 14	15
Manufacturing Operations [Member] \| Convertible Subordinated Debt [Member] \| Four Point Five Zero Senior Subordinated Convertible Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage			4.50%
Manufacturing Operations [Member] \| Convertible Subordinated Debt [Member] \| Four Point Seven Five Senior Subordinated Convertible Notes [Member] [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage			4.75%
Manufacturing Operations [Member] \| Tax Exempt Bond [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage			6.75%
Long-term Debt		220	$ 220
Debt Issuance Costs, Net	$ 5	5
Manufacturing Operations [Member] \| Financed lease obligations [Member]
Debt Instrument [Line Items]
Long-term Debt		60	53
Manufacturing Operations [Member] \| Notes Payable, Other Payables [Member]
Debt Instrument [Line Items]
Long-term Debt		$ 11	$ 9