On January $1,2024,$ Medical Transport Company$$s accumulated postretirement benefit obligation was $$100$ million. At the end of $2024,$ retiree benefits paid were $$13$ million. Service cost for $2024$ is $$9$ million. Assumptions regarding the trend of future health care costs were revised at the end of $2024,$ causing the actuary to revise downward the estimate of the APBO by $$6$ million. The actuary$$s discount rate is $8\%.$

Determine the amount of the accumulated postretirement benefit obligation at December $31,2024.$