Earnings (loss) per common share (“EPS”) - Schedule of Antidilutive Securities Excluded From Computation of Earnings Per Share (Details) - shares shares in Millions	3 Months Ended		6 Months Ended
	Aug. 04, 2018	Jul. 29, 2017	Aug. 04, 2018	Jul. 29, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive shares excluded from the calculation of earnings per share (shares)	7.1	0.0	7.1	6.7
Share awards
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive shares excluded from the calculation of earnings per share (shares)	0.3	0.0	0.3	0.0
Potential impact of preferred shares
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive shares excluded from the calculation of earnings per share (shares)	6.8	0.0	6.8	6.7