Retirement Benefit Plans
 3 Months Ended
Apr. 30, 2016
Retirement Benefit Plans [Abstract]  
Retirement Benefit Plans
Retirement Benefit Plans
The components of net periodic benefit expense/(income) for our non-contributory qualified defined benefit pension plan (Primary Pension Plan) and non-contributory supplemental pension plans were as follows:
 
Three Months Ended
($ in millions)
April 30,
2016
 
May 2,
2015
Primary Pension Plan
 
 
 
Service cost
$
14

 
$
17

Interest cost
38

 
49

Expected return on plan assets
(54
)
 
(89
)
Amortization of prior service cost/(credit)
2

 
2

Net periodic benefit expense/(income)
$
—

 
$
(21
)
 
 
 
 
Supplemental Pension Plans
 
 
 
Interest cost
2

 
2

Net periodic benefit expense/(income)
$
2

 
$
2

 
 
 
 
Primary and Supplemental Pension Plans Total
 
 
 
Service cost
$
14

 
$
17

Interest cost
40

 
51

Expected return on plan assets
(54
)
 
(89
)
Amortization of prior service cost/(credit)
2

 
2

Net periodic benefit expense/(income)
$
2

 
$
(19
)

Additionally, the Company had net periodic postretirement income of $4 million and $2 million in the three months ended April 30, 2016 and May 2, 2015. These amounts are related to the Company's noncontributory postretirement health and welfare plan and is included in SG&A expense in the unaudited Interim Consolidated Statements of Operations. The Company communicated to plan participants that the plan will terminate by December 2016 and this resulted in a reduction of the accumulated plan benefit obligation from $8 million at January 30, 2016 to $1 million at April 30, 2016.