Summary of Significant Accounting Policies Advertising (Details) - USD ($) $ in Millions	12 Months Ended
	Jan. 31, 2018	Jan. 31, 2017	Jan. 31, 2016
Marketing and Advertising Expense [Abstract]
Advertising, Marketing, Public and Media Relations Costs	$ 314.9	$ 299.0	$ 302.0
Advertising costs as Percentage of Net Sales	7.60%	7.50%	7.40%