Build the cost line by line
List flights, hotels, cruises, tours and other prepaid bookings. Mark what is refundable and what is not.
Allocate cost by traveler
If a policy asks for per-person trip cost, use booking records rather than dividing blindly.
Update major changes
Adding a cruise, tour or nonrefundable hotel later can change the amount at risk and may need to be reported.
Keep receipts
Trip-cost documentation also becomes claim documentation if cancellation or interruption occurs.