Pension | OPEB | ||||||||||||||||||||||
2013 | 2012 | 2011 | 2013 | 2012 | 2011 | ||||||||||||||||||
(Millions of Dollars) | |||||||||||||||||||||||
Net Periodic Benefit Cost | |||||||||||||||||||||||
Service cost | $ | 14.6 | $ | 21.7 | $ | 15.9 | $ | 10.0 | $ | 10.3 | $ | 10.4 | |||||||||||
Interest cost | 60.4 | 65.5 | 67.6 | 15.6 | 20.3 | 20.8 | |||||||||||||||||
Expected return on plan assets | (95.8 | ) | (89.6 | ) | (82.1 | ) | (21.3 | ) | (19.0 | ) | (16.9 | ) | |||||||||||
Amortization of: | |||||||||||||||||||||||
Transition obligation | — | — | — | — | 0.3 | 0.3 | |||||||||||||||||
Prior service cost (credit) | 2.3 | 2.2 | 2.2 | (2.0 | ) | (1.9 | ) | (1.9 | ) | ||||||||||||||
Actuarial loss | 54.5 | 41.0 | 34.0 | 3.7 | 7.3 | 6.2 | |||||||||||||||||
Settlement charge | 2.5 | — | — | — | — | — | |||||||||||||||||
Other | — | 0.4 | — | — | — | — | |||||||||||||||||
Net Periodic Benefit Cost | $ | 38.5 | $ | 41.2 | $ | 37.6 | $ | 6.0 | $ | 17.3 | $ | 18.9 | |||||||||||
Pension | OPEB | ||||||||||
2013 | 2012 | 2011 | 2013 | 2012 | 2011 | ||||||
Weighted-Average assumptions used to | |||||||||||
determine benefit obligations as of Dec. 31 | |||||||||||
Discount rate | 5.00% | 4.10% | 5.05% | 4.95% | 4.15% | 5.20% | |||||
Rate of compensation increase | 4.0% | 4.0% | 4.0% | N/A | N/A | N/A | |||||
Weighted-Average assumptions used to | |||||||||||
determine net cost for year ended Dec. 31 | |||||||||||
Discount rate | 4.10% | 5.05% | 5.60% | 4.15% | 5.20% | 5.70% | |||||
Expected return on plan assets | 7.25% | 7.25% | 7.25% | 7.50% | 7.50% | 7.50% | |||||
Rate of compensation increase | 4.0% | 4.0% | 4.0% | N/A | N/A | N/A | |||||
Assumed health care cost trend rates as of Dec. 31 | 2013 | 2012 | 2011 | |||
Health care cost trend rate assumed for next year (Pre 65 / Post 65) | 7.5%/7.5% | 7.5%/7.5% | 8.0%/12% | |||
Rate that the cost trend rate gradually adjusts to | 5.0% | 5.0% | 5.0% | |||
Year that the rate reaches the rate it is assumed to remain at (Pre 65 / Post 65) | 2021/2021 | 2017/2017 | 2017/2017 | |||