The components of net periodic benefit expense/(income) for our non-contributory qualified defined benefit pension plan (Primary Pension Plan), non-contributory supplemental pension plans and contributory postretirement health and welfare plan were as follows: | | | | | | | | | | | | | | | | | | Three Months Ended | | Six Months Ended | ($ in millions) | August 2,
2014 | | August 3,
2013 | | August 2,
2014 | | August 3,
2013 | Primary Pension Plan | | | | | | | | Service cost | $ | 16 |
| | $ | 19 |
| | $ | 31 |
| | $ | 39 |
| Interest cost | 52 |
| | 51 |
| | 105 |
| | 102 |
| Expected return on plan assets | (87 | ) | | (85 | ) | | (174 | ) | | (170 | ) | Amortization of actuarial loss/(gain) | 12 |
| | 38 |
| | 25 |
| | 76 |
| Amortization of prior service cost/(credit) | 3 |
| | 2 |
| | 4 |
| | 3 |
| Net periodic benefit expense/(income) | $ | (4 | ) | | $ | 25 |
| | $ | (9 | ) | | $ | 50 |
| | | | | | | | | Supplemental Pension Plans | | | | | | | | Service cost | $ | — |
| | $ | — |
| | $ | — |
| | $ | — |
| Interest cost | 2 |
| | 3 |
| | 4 |
| | 6 |
| Amortization of actuarial loss/(gain) | 4 |
| | 6 |
| | 8 |
| | 12 |
| Amortization of prior service cost/(credit) | — |
| | — |
| | — |
| | — |
| Net periodic benefit expense/(income) | $ | 6 |
| | $ | 9 |
| | $ | 12 |
| | $ | 18 |
| | | | | | | | | Primary and Supplemental Pension Plans Total | | | | | | | | Service cost | $ | 16 |
| | $ | 19 |
| | $ | 31 |
| | $ | 39 |
| Interest cost | 54 |
| | 54 |
| | 109 |
| | 108 |
| Expected return on plan assets | (87 | ) | | (85 | ) | | (174 | ) | | (170 | ) | Amortization of actuarial loss/(gain) | 16 |
| | 44 |
| | 33 |
| | 88 |
| Amortization of prior service cost/(credit) | 3 |
| | 2 |
| | 4 |
| | 3 |
| Net periodic benefit expense/(income) | $ | 2 |
| | $ | 34 |
| | $ | 3 |
| | $ | 68 |
| | | | | | | | | Postretirement Health and Welfare Plan | | | | | | | | Service cost | $ | — |
| | $ | — |
| | $ | — |
| | $ | — |
| Interest cost | — |
| | — |
| | — |
| | — |
| Amortization of actuarial loss/(gain) | — |
| | — |
| | — |
| | — |
| Amortization of prior service cost/(credit) | (2 | ) | | (2 | ) | | (4 | ) | | (4 | ) | Net periodic benefit expense/(income) | $ | (2 | ) | | $ | (2 | ) | | $ | (4 | ) | | $ | (4 | ) | | | | | | | | | Retirement Benefit Plans Total | | | | | | | | Service cost | $ | 16 |
| | $ | 19 |
| | $ | 31 |
| | $ | 39 |
| Interest cost | 54 |
| | 54 |
| | 109 |
| | 108 |
| Expected return on plan assets | (87 | ) | | (85 | ) | | (174 | ) | | (170 | ) | Amortization of actuarial loss/(gain) | 16 |
| | 44 |
| | 33 |
| | 88 |
| Amortization of prior service cost/(credit) | 1 |
| | — |
| | — |
| | (1 | ) | Net periodic benefit expense/(income) | $ | — |
| | $ | 32 |
| | $ | (1 | ) | | $ | 64 |
|
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