v3.26.1
Average Annual Total Returns - Natixis Funds Trust II
 12 Months Ended 60 Months Ended 104 Months Ended 120 Months Ended
Dec. 31, 2025
Dec. 31, 2025
Dec. 31, 2025
Dec. 31, 2025
Loomis Sayles Strategic Alpha Fund | Bloomberg U.S. Aggregate Bond Index        
Prospectus [Line Items]        
Average Annual Return, Percent 7.30% (0.36%) 1.84% 2.01%
Loomis Sayles Strategic Alpha Fund | ICE BofA 3-Month U.S. Treasury Bill Index        
Prospectus [Line Items]        
Average Annual Return, Percent 4.18% 3.17% 2.45% 2.18%
Loomis Sayles Strategic Alpha Fund | Classs A        
Prospectus [Line Items]        
Average Annual Return, Percent 3.73% 2.28%   3.47%
Loomis Sayles Strategic Alpha Fund | Classs C        
Prospectus [Line Items]        
Average Annual Return, Percent 6.48% 2.39%   3.29%
Loomis Sayles Strategic Alpha Fund | Classs N        
Prospectus [Line Items]        
Average Annual Return, Percent 8.62% 3.47% 3.93%  
Loomis Sayles Strategic Alpha Fund | Classs Y        
Prospectus [Line Items]        
Average Annual Return, Percent 8.58% 3.42%   4.17%
Loomis Sayles Strategic Alpha Fund | Classs Y | After Taxes on Distributions        
Prospectus [Line Items]        
Average Annual Return, Percent 6.52% 1.60%   2.64%
Loomis Sayles Strategic Alpha Fund | Classs Y | After Taxes on Distributions and Sales        
Prospectus [Line Items]        
Average Annual Return, Percent 5.05% 1.80%   2.54%
Natixis Oakmark Fund | S&P 500® Index        
Prospectus [Line Items]        
Average Annual Return, Percent 17.88% 14.42% 14.77% 14.82%
Natixis Oakmark Fund | Classs A        
Prospectus [Line Items]        
Average Annual Return, Percent 8.26% 13.78%   13.01%
Natixis Oakmark Fund | Classs C        
Prospectus [Line Items]        
Average Annual Return, Percent 13.03% 14.28%   13.00%
Natixis Oakmark Fund | Classs N        
Prospectus [Line Items]        
Average Annual Return, Percent 15.20% 15.51% 13.48%  
Natixis Oakmark Fund | Classs Y        
Prospectus [Line Items]        
Average Annual Return, Percent 15.15% 15.43%   13.97%
Natixis Oakmark Fund | Classs Y | After Taxes on Distributions        
Prospectus [Line Items]        
Average Annual Return, Percent 13.32% 13.43%   12.03%
Natixis Oakmark Fund | Classs Y | After Taxes on Distributions and Sales        
Prospectus [Line Items]        
Average Annual Return, Percent 10.16% 12.00%   11.06%
Vaughan Nelson Mid Cap Fund | Russell Midcap® Value Index        
Prospectus [Line Items]        
Average Annual Return, Percent 11.05% 9.83%   9.78%
Vaughan Nelson Mid Cap Fund | Russell 3000® Index        
Prospectus [Line Items]        
Average Annual Return, Percent 17.15% 13.15%   14.29%
Vaughan Nelson Mid Cap Fund | Classs A        
Prospectus [Line Items]        
Average Annual Return, Percent 5.67% 9.49%   8.55%
Vaughan Nelson Mid Cap Fund | Classs C        
Prospectus [Line Items]        
Average Annual Return, Percent 10.59% 9.98%   8.53%
Vaughan Nelson Mid Cap Fund | Classs Y        
Prospectus [Line Items]        
Average Annual Return, Percent 12.39% 11.08%   9.47%
Vaughan Nelson Mid Cap Fund | Classs Y | After Taxes on Distributions        
Prospectus [Line Items]        
Average Annual Return, Percent 1.84% 7.33%   6.88%
Vaughan Nelson Mid Cap Fund | Classs Y | After Taxes on Distributions and Sales        
Prospectus [Line Items]        
Average Annual Return, Percent 11.43% 8.08%   7.10%
Vaughan Nelson Mid Cap Fund | Classs N        
Prospectus [Line Items]        
Average Annual Return, Percent 12.44% 11.13%   9.54%