v3.25.1
Average Annual Total Returns - FidelitySAIUSTreasuryBondIndexFund-PRO - FidelitySAIUSTreasuryBondIndexFund-PRO - Fidelity SAI U.S. Treasury Bond Index Fund
Apr. 29, 2025
Fidelity SAI U.S. Treasury Bond Index Fund | Return Before Taxes  
Average Annual Return:  
Past 1 year 0.72%
Past 5 years (0.69%)
Since Inception 0.51% [1]
Fidelity SAI U.S. Treasury Bond Index Fund | After Taxes on Distributions  
Average Annual Return:  
Past 1 year (0.46%)
Past 5 years (1.57%)
Since Inception (0.33%) [1]
Fidelity SAI U.S. Treasury Bond Index Fund | After Taxes on Distributions and Sales  
Average Annual Return:  
Past 1 year 0.43%
Past 5 years (0.81%)
Since Inception 0.08% [1]
LB001  
Average Annual Return:  
Past 1 year 1.25%
Past 5 years (0.33%)
Since Inception 1.27%
LB009  
Average Annual Return:  
Past 1 year 0.58%
Past 5 years (0.68%)
Since Inception 0.56%
[1]
A From March 1, 2016 .