Credit transaction, net - Narrative (Details) - USD ($) $ in Millions	1 Months Ended		3 Months Ended		12 Months Ended
	Mar. 31, 2018	Oct. 28, 2017	May 05, 2018	Apr. 29, 2017	Feb. 02, 2019	Feb. 03, 2018
Debt Instrument [Line Items]
Credit transaction, net			$ (143.1)	$ 0.0
Initial credit term (years)				7 years
Credit renewal term (years)				2 years
Sale of receivables, percentage of par	72.00%
Sale of receivables, percentage settled in cash	95.00%
Sale of receivables. percentage deferred until second anniversary	5.00%
Reversal of allowance on receivables previously held for sale			141.0	$ 0.0
Securitization Facility
Debt Instrument [Line Items]
Repayments of secured debt						$ (600.0)
Consumer Portfolio Segment
Debt Instrument [Line Items]
Reversal of allowance on receivables previously held for sale			107.6	$ 0.0
Sterling Jewelers, Inc. | Consumer Portfolio Segment
Debt Instrument [Line Items]
Net proceeds		$ 952.5
Genesis Financial Solution
Debt Instrument [Line Items]
Servicing agreement, term (years)		5 years
Forecast | Consumer Portfolio Segment | Sterling Jewelers
Debt Instrument [Line Items]
Reversal of allowance on receivables previously held for sale					$ (141.0)
Forecast | Consumer Portfolio Segment | Other
Debt Instrument [Line Items]
Transaction-related costs			$ 2.1