Accounts receivable, net - Credit Quality Indicator and Age Analysis (Details) - USD ($) $ in Millions	Oct. 29, 2016	Jan. 30, 2016	Oct. 31, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross	$ (1,679.3)	$ (1,855.9)	$ (1,559.4)
Valuation allowance	$ (133.0)	$ (130.0)	$ (122.2)
Gross	100.00%	100.00%	100.00%
Valuation allowance	7.90%	7.00%	7.80%
Current, aged 0 – 30 days | Performing Financing Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross	$ (1,294.9)	$ (1,473.0)	$ (1,212.2)
Valuation allowance	$ (39.3)	$ (45.4)	$ (36.8)
Gross	77.20%	79.40%	77.70%
Valuation allowance	3.00%	3.10%	3.00%
Past due, aged 31 – 60 days | Performing Financing Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross	$ (250.6)	$ (259.6)	$ (226.0)
Valuation allowance	$ (8.1)	$ (8.3)	$ (7.3)
Gross	14.90%	14.00%	14.50%
Valuation allowance	3.20%	3.20%	3.20%
Past due, aged 61 – 90 days | Performing Financing Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross	$ (50.7)	$ (49.2)	$ (45.2)
Valuation allowance	$ (2.5)	$ (2.2)	$ (2.1)
Gross	3.00%	2.60%	2.90%
Valuation allowance	4.90%	4.50%	4.60%
Past due, aged more than 90 days | Nonperforming Financing Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross	$ (83.1)	$ (74.1)	$ (76.0)
Valuation allowance	$ (83.1)	$ (74.1)	$ (76.0)
Gross	4.90%	4.00%	4.90%
Valuation allowance	100.00%	100.00%	100.00%