Accounts receivable, net - Portfolio of Accounts Receivable (Details) - USD ($) $ in Millions	Apr. 29, 2017	Jan. 28, 2017	Apr. 30, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, net	$ 1,726.3	$ 1,858.0	$ 1,689.3
Consumer Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, net	1,683.8		1,654.3
Other Accounts Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, net	9.7	11.3	13.4
Sterling Jewelers | Consumer Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, net	1,683.8	1,813.3	1,654.3
Zale Jewelry | Consumer Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, net	$ 32.8	$ 33.4	$ 21.6