What was found
HALFWAY THROUGH OUR FLIGHT, AS WE BEGAN OUR INITIAL DESCENT, THE RT ENG ROLLED BACK TO IDLE. THERE WERE NO INDICATIONS, & THERE WERE NO EICAS MESSAGES. PUSH FDR EVENT BUTTON. 10 TO 15 MINS LATER, THE RT AMBER ENG MESSAGE ILLUMINATED. RAN QRC CHECKLIST & SHUTDOWN RT ENGINE. DECLARED AN EMERGENCY & LANDED NORMALLY AT DTW. PERFORMED A GVI OF THE RIGHT ENGINE WITH NO DEFECTS NOTED, GAINED ACCESS TO P3 LINE AND FOUND THE LINE BROKE COMING OUT OF THE COMBUSTER CASE, REMOVED AND REPLACED RIGHT ENGINE P3 LINE IAW SEI-780 REV 64 DATED 2/1/2024 SM MAINTENANCE PRACTICE 07, COMPLIED WITH POST INSTALLATION ENGINE RUNS ALL CHECK SATISFACTORY.