Income Taxes U.S. Tax Reform (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Jan. 31, 2019	Oct. 31, 2018	Jan. 31, 2019	Jan. 31, 2018	Jan. 31, 2017
Statutory Accounting Practices [Line Items]
US Tax Act Impact - Transition Tax	$ (25.2)	$ (24.0)	$ 49.2	$ (101.1)
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent			21.00%	33.80%	35.00%
Tax Year 2017 [Member]
Statutory Accounting Practices [Line Items]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent				35.00%
Tax Year 2018 [Member]
Statutory Accounting Practices [Line Items]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent				21.00%