Pension Benefits | Other Postretirement Benefits | |||||||||||||||||||||||
(in millions) | 2013 | 2012 | 2011 | 2013 | 2012 | 2011 | ||||||||||||||||||
Service cost—benefits earned during the year | $ | 39.0 | $ | 35.0 | $ | 30.0 | $ | 3.2 | $ | 3.1 | $ | 3.2 | ||||||||||||
Interest cost on benefits earned in prior years | 122.8 | 132.4 | 135.1 | 22.4 | 26.1 | 27.5 | ||||||||||||||||||
Expected return on plan assets | (176.0 | ) | (181.4 | ) | (192.1 | ) | (0.5 | ) | (0.8 | ) | (1.0 | ) | ||||||||||||
Amortization of prior service cost (credit) | 3.0 | 6.4 | 11.3 | (18.2 | ) | (18.2 | ) | (18.3 | ) | |||||||||||||||
Amortization of net actuarial loss | 111.8 | 105.2 | 71.3 | 17.2 | 14.6 | 9.9 | ||||||||||||||||||
Termination benefits | 4.8 | — | 0.8 | 1.3 | — | 0.2 | ||||||||||||||||||
Total retirement benefit expense | $ | 105.4 | $ | 97.6 | $ | 56.4 | $ | 25.4 | $ | 24.8 | $ | 21.5 | ||||||||||||