FINANCIAL STATEMENT SCHEDULE II (Details) - USD ($) $ in Millions	12 Months Ended
	Jan. 31, 2018	Jan. 31, 2017	Jan. 31, 2016
Allowance for doubtful accounts
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at the Beginning of Year	$ 1.5	$ 7.6	$ 6.3
Additions Charged to Costs and Expenses or Revenues	2.1	(3.3)	2.3
Deductions and Write-Offs	1.3	2.8	1.0
Balance at End of Year	2.3	1.5	7.6
Partner Program reserves
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at the Beginning of Year	28.1	45.2	36.5
Additions Charged to Costs and Expenses or Revenues	224.3	240.3	267.4
Deductions and Write-Offs	215.9	257.4	258.7
Balance at End of Year	36.5	28.1	45.2
Restructuring
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at the Beginning of Year	8.4	1.3	1.6
Additions Charged to Costs and Expenses or Revenues	94.1	77.8	0.0
Deductions and Write-Offs	45.3	70.7	0.3
Balance at End of Year	$ 57.2	$ 8.4	$ 1.3