Loomis Sayles Global Allocation Fund S000006698 [Member] Loomis Sayles Small Cap Growth Fund S000006705 [Member] Loomis Sayles Strategic Income Fund S000006706 [Member] Bench 202401191097 [Member] Bench 202404231134 [Member] Bench 202401191098 [Member] Class C C000027671 [Member] Class Y C000018254 [Member] Class N C000182249 [Member] Class T C000188534 [Member] Admin Class C000082999 [Member] C000125487 [Member] C000188539 [Member] Class A C000018251 [Member] C000018226 [Member] Institutional Class C000018249 [Member] C000027670 [Member] Retail Class C000018250 [Member] Class B C000018252 [Member] C000125486 [Member] C000018253 [Member]