Loomis Sayles Strategic Alpha Fund Loomis Sayles Strategic Alpha Fund Natixis Oakmark Fund Natixis Oakmark Fund Vaughan Nelson Mid Cap Fund Vaughan Nelson Mid Cap Fund Dloomisharrisstatutoryprospectus_4833 Natixis Funds Trust II Dmultiaffiliatestatutoryprospectus_4824 Natixis Funds Trust II Dloomisharrisfundssai_4822 5-1 Loomis Harris Funds_SAI Dmultiaffiliatefundssai_4823 5-1 Multi-Affiliate Funds_SAI Class A - C000094853 Classs A Class C - C000094854 Classs C Class N - C000190722 Classs N Class T - C000188568 Classs T Class Y - C000094855 Classs Y Class A - C000021802 Classs A Class B - C000021803 Classs B Class C - C000021804 Classs C Class N - C000190720 Classs N Class T - C000188564 Classs T Class Y - C000021805 Classs Y Class A - C000069913 Classs A Class C - C000069914 Classs C Class Y - C000069915 Classs Y Class N - C000128764 Classs N Class T - C000188566 Classs T Agency Securities Risk Agency Securities Risk [Member] Inflation/Deflation Risk Inflation/Deflation Risk [Member] Models and Data Risk Models and Data Risk [Member] Short Exposure risk Short Exposure risk [Member] Bloomberg U.S. Aggregate Bond Index Bloomberg U.S. Aggregate Bond Index ICE BofA 3-Month U.S. Treasury Bill Index ICE BofA 3-Month U.S. Treasury Bill Index Bank Loans Risk Bank Loans Risk [Member] Below Investment Grade Fixed-Income Securities Risk Below Investment Grade Fixed-Income Securities Risk [Member] Derivatives Risk Derivatives Risk [Member] Interest Rate Risk Interest Rate Risk [Member] Leverage Risk Leverage Risk [Member] Mortgage-Related and Asset-Backed Securities Risk Mortgage-Related and Asset-Backed Securities Risk [Member] Portfolio Turnover Rate Risk Portfolio Turnover Rate Risk [Member] Options Risk Options Risk [Member] Currency Risk Currency Risk [Member] Focused Investment Risk Focused Investment Risk [Member] Value Style Risk Value Style Risk [Member] Equity Securities Risk Equity Securities Risk [Member] Market/Issuer Risk Market/Issuer Risk [Member] Management Risk Management Risk [Member] Large Shareholder Transaction Risk Large Shareholder Transaction Risk [Member] Liquidity Risk Liquidity Risk [Member] Small- and Mid-Capitalization Companies Risk Small- and Mid-Capitalization Companies Risk [Member] Credit/Counterparty Risk Credit/Counterparty Risk [Member] Cybersecurity and Technology Risk Cybersecurity and Technology Risk [Member] Emerging Markets Risk Emerging Markets Risk [Member] Foreign Securities Risk Foreign Securities Risk [Member] REITs Risk REITs Risk [Member] S&P 500® Index S&P 500® Index Investments in Other Investment Companies Risk Investments in Other Investment Companies Risk [Member] Russell Midcap® Value Index Russell Midcap® Value Index Russell 3000® Index Russell 3000® Index