Quarterly report pursuant to Section 13 or 15(d)

Retirement Benefit Plans (Net Periodic Expense) (Details)

v3.8.0.1
Retirement Benefit Plans (Net Periodic Expense) (Details) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Oct. 28, 2017
Oct. 29, 2016
Oct. 28, 2017
Oct. 29, 2016
Mar. 31, 2017
Jan. 28, 2017
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]            
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate 3.94%   3.94%   4.34% 4.40%
Net periodic benefit expense/(income) $ 9 $ 1 $ 3 $ 5    
Other Postretirement Benefits Plan [Member]            
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]            
Net periodic benefit expense/(income)   (6)   (14)    
Primary Pension Plan            
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]            
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Settlement $ (195)          
Defined Benefit Plan, Funded Status of Plan, Percent 100.00%   100.00%   98.00%  
Service cost $ 11 14 $ 32 41    
Interest cost 36 38 109 114    
Expected return on plan assets (53) (54) (160) (161)    
Amortization of prior service cost/(credit) 1 2 5 6    
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement (12)   (12)      
Net periodic benefit expense/(income) 7 0 (2) 0    
Supplemental Pension Plans            
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]            
Service cost 0 0 0 0    
Interest cost 2 1 5 5    
Net periodic benefit expense/(income) 2 1 5 5    
Primary and Supplemental Pension Plans Total [Member]            
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]            
Service cost 11 14 32 41    
Interest cost 38 39 114 119    
Expected return on plan assets (53) (54) (160) (161)    
Amortization of prior service cost/(credit) 1 2 5 6    
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement (12)   (12)      
Net periodic benefit expense/(income) $ 9 $ 1 $ 3 $ 5