On January 1, 2024, Medical Transport Company's accumulated postretirement benefit obligation was $25 million. At the end of 2024 , retiree benefits paid were $7 million. Service cost for 2024 is $3 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 $2 million. The actuary's discount rate is 8%. Determine the amount of the accumulated postretirement benefit obligation at December 31, 2024. Note: Enter your answer in millions (i.e., 10,000,000 should be entered as 10)