Accounts receivable, net - Portfolio of Accounts Receivable (Details) (USD $) In Millions, unless otherwise specified	May 02, 2015	Jan. 31, 2015	May 03, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, net	$ 1,499.9	$ 1,567.6	$ 1,308.2
Consumer Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, net	1,489.4	1,552.9	1,294.8
Other Accounts Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, net	$ 10.5	$ 14.7	$ 13.4