Long-Lived Assets - Impairment of Long-Lived Assets Held and Used (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Oct. 31, 2020	Oct. 31, 2020
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment	$ 0	$ 214
Store Asset Impairment
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment	0	111
Operating Lease Asset Impairment
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment	$ 0	$ 103