DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES - Gross amounts of derivative instruments, amounts offset due to master netting agreements (Details) - USD ($) $ in Millions	Jul. 31, 2020	Jan. 31, 2020
Financial assets
Gross Amounts of Recognized Assets/ (Liabilities)	$ 594	$ 299
Gross Amounts Offset in the Statement of Financial Position	(256)	(218)
Net Amounts of Assets/ (Liabilities) Presented in the Statement of Financial Position	338	81
Financial Instruments	0	0
Cash Collateral Received or Pledged	0	0
Net Amount	338	81
Financial liabilities
Gross Amounts of Recognized Assets/ (Liabilities)	(575)	(286)
Gross Amounts Offset in the Statement of Financial Position	256	218
Net Amounts of Assets/ (Liabilities) Presented in the Statement of Financial Position	(319)	(68)
Financial Instruments	0	0
Cash Collateral Received or Pledged	0	15
Net Amount	(319)	(53)
Total derivative instruments
Gross Amounts of Recognized Assets/ (Liabilities)	19	13
Gross Amounts Offset in the Statement of Financial Position	0	0
Net Amounts of Assets/ (Liabilities) Presented in the Statement of Financial Position	19	13
Financial Instruments	0	0
Cash Collateral Received or Pledged	0	15
Net Amount	$ 19	$ 28