Pension Benefits | Other Retirement Benefits | |||||||||||||||
(in millions) | 2013 | 2012 | 2013 | 2012 | ||||||||||||
PBO at beginning of period | $ | 3,967 | $ | 3,518 | $ | 254 | $ | 254 | ||||||||
Service cost | 10 | 8 | 4 | 4 | ||||||||||||
Interest cost | 139 | 153 | 8 | 10 | ||||||||||||
Discount rate and other assumption changes | (319 | ) | 408 | (19 | ) | 25 | ||||||||||
Actuarial losses (gains) | 19 | 57 | (20 | ) | (7 | ) | ||||||||||
Plan amendments | — | — | 1 | (16 | ) | |||||||||||
Plan participant contributions | — | — | 5 | 8 | ||||||||||||
Benefits paid | (160 | ) | (175 | ) | (19 | ) | (24 | ) | ||||||||
Other | 4 | (2 | ) | — | — | |||||||||||
PBO at end of period | 3,660 | 3,967 | 214 | 254 | ||||||||||||
Plan assets at beginning of period | 2,501 | 2,111 | 12 | 9 | ||||||||||||
Actual return on plan assets | 317 | 437 | 1 | 2 | ||||||||||||
Company contributions | 122 | 126 | 15 | 17 | ||||||||||||
Plan participant contributions | — | — | 5 | 8 | ||||||||||||
Benefits paid | (160 | ) | (175 | ) | (19 | ) | (24 | ) | ||||||||
Other | (1 | ) | 2 | — | — | |||||||||||
Plan assets at end of period | 2,779 | 2,501 | 14 | 12 | ||||||||||||
Funded status of plans | $ | (881 | ) | $ | (1,466 | ) | $ | (200 | ) | $ | (242 | ) | ||||
Funded status consists of: | ||||||||||||||||
Retirement benefits liability | $ | (879 | ) | $ | (1,461 | ) | $ | (198 | ) | $ | (231 | ) | ||||
Compensation and benefits liability | (12 | ) | (11 | ) | (2 | ) | (11 | ) | ||||||||
Other assets | 10 | 6 | — | — | ||||||||||||
Net liability | $ | (881 | ) | $ | (1,466 | ) | $ | (200 | ) | $ | (242 | ) |