The Kollar Company has a defined benefit pension plan. Pension information concerning the fiscal years 2024 and 2025 are presented below ($ in millions): Information Provided by Pension Plan Actuary:
a. Projected benefit obligation as of December 31, 2023 = $1,800.
b. Prior service cost from plan amendment on January 2, 2024 = $400 (straight-line amortization for 10-year average remaining service period).
c. Service cost for 2024 = $520.
d. Service cost for 2025 = $570.
e. Discount rate used by actuary on projected benefit obligation for 2024 and 2025 = 10%.
f. Payments to retirees in 2024 = $380.
g. Payments to retirees in 2025 = $450.
h. No changes in actuarial assumptions or estimates.
i. Net gain—AOCI on January 1, 2024 = $230.
j. Net gains and losses are amortized for 10 years in 2024 and 2025. Information Provided by Pension Fund Trustee:
a. Plan asset balance at fair value on January 1, 2024 = $1,600.
b. 2024 contributions = $540.
c. 2025 contributions = $590.
d. Expected long-term rate of return on plan assets = 12%.
e. 2024 actual return on plan assets = $180.
f. 2025 actual return on plan assets = $210.

Required:
1. Calculate pension expense for 2024 and 2025.
2. Prepare the journal entries for 2024 and 2025 to record pension expense.
3. Prepare the journal entries for 2024 and 2025 to record any gains and losses and new prior service cost.
4. Prepare the journal entries for 2024 and 2025 to record (a) the cash contribution to plan assets and (b) the benefit payments to retirees.