FINANCIAL STATEMENT SCHEDULE II (Details) - USD ($) $ in Millions	12 Months Ended
	Jan. 31, 2019	Jan. 31, 2018	Jan. 31, 2017
Partner Program reserves
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at the Beginning of Year	$ 36.5	$ 28.1	$ 45.2
Additions Charged to Costs and Expenses or Revenues	294.7	224.3	240.3
Deductions and Write-Offs	279.5	215.9	257.4
Balance at End of Year	51.7	36.5	28.1
Restructuring and other facility exit costs
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at the Beginning of Year	57.2	8.4	1.3
Additions Charged to Costs and Expenses or Revenues	41.9	94.1	77.8
Deductions and Write-Offs	97.0	45.3	70.7
Balance at End of Year	$ 2.1	$ 57.2	$ 8.4