The components of net periodic pension expense/(income) for our non-contributory qualified defined benefit pension plan and supplemental pension plans were as follows: | | | | | | | | | | | | | | | | | | | | | | | | | | Three Months Ended | | Six Months Ended | | ($ in millions) | August 1,
2020 | | August 3,
2019 | | August 1,
2020 | | August 3,
2019 | | Service cost | $ | 8 | | | $ | 7 | | | $ | 16 | | | $ | 14 | | | | | | | | | | | Other components of net periodic pension cost/(income): | | | | | | | | | Interest cost | 26 | | | 33 | | | 52 | | | 66 | | | Expected return on plan assets | (51) | | | (48) | | | (101) | | | (96) | | | Amortization of prior service cost | 2 | | | 2 | | | 3 | | | 4 | | |
| Amortization of net loss | 1 | | | — | | | 1 | | | — | | | Curtailment loss recognized | 5 | | | — | | | 5 | | | — | | | Special termination benefit cost recognized | 94 | | | — | | | 94 | | | — | | | 77 | | | (13) | | | 54 | | | (26) | | | Net periodic pension expense/(income) | $ | 85 | | | $ | (6) | | | $ | 70 | | | $ | (12) | |
|