v3.26.3
State Street Loomis Sayles Opportunistic Bond ETF Average Annual Total Returns
 12 Months Ended 46 Months Ended 51 Months Ended 59 Months Ended 60 Months Ended 81 Months Ended 117 Months Ended 120 Months Ended
Jun. 30, 2026
Dec. 31, 2025
Dec. 31, 2025
Dec. 31, 2025
Dec. 31, 2025
Dec. 31, 2025
Dec. 31, 2025
Dec. 31, 2025
Dec. 31, 2025
Bloomberg U.S. Aggregate Bond Index (reflects no deduction for fees, expenses or taxes)[Member]                  
Prospectus [Line Items]                  
Average Annual Return, Percent   7.30% 1.01% (0.12%) (0.17%) (0.36%) 1.67% 1.72% 2.01%
State Street Loomis Sayles Opportunistic Bond Composite Index (reflects no deduction for fees, expenses or taxes)[Member]                  
Prospectus [Line Items]                  
Average Annual Return, Percent [1]   7.53%   2.71%          
State Street Loomis Sayles Opportunistic Bond ETF                  
Prospectus [Line Items]                  
Average Annual Return, Percent   7.92%   2.29%          
Performance Inception Date Sep. 27, 2021                
State Street Loomis Sayles Opportunistic Bond ETF | After Taxes on Distributions                  
Prospectus [Line Items]                  
Average Annual Return, Percent   5.20%   (0.01%)          
State Street Loomis Sayles Opportunistic Bond ETF | After Taxes on Distributions and Sales                  
Prospectus [Line Items]                  
Average Annual Return, Percent   4.64%   0.72%          
[1] A composite benchmark the Fund seeks to outperform, comprising 50% investment grade corporate bonds, 25% high yield corporate bonds, and 25% senior loans.