Annual report pursuant to Section 13 and 15(d)

Postretirement Health Care and Life Insurance Benefits (Narrative) (Details)

v3.7.0.1
Postretirement Health Care and Life Insurance Benefits (Narrative) (Details) - USD ($)
$ in Millions
12 Months Ended
Jan. 28, 2017
Jan. 30, 2016
Jan. 31, 2015
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]      
2016 reduction in service cost and interest cost $ 36    
Other Postretirement Benefit Plan [Member]      
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]      
Discount rate 3.14% 3.55% 4.50%
2016 reduction in service cost and interest cost $ 2    
Previously Reported | Other Postretirement Benefit Plan [Member]      
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]      
Discount rate 4.15%