State Street Nuveen Municipal 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 3-15 Year Blend (2-17) Municipal Bond Index (reflects no deduction for fees, expenses or taxes)[Member]
Prospectus [Line Items]
Average Annual Return, Percent		5.30%			1.00%
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 Nuveen Municipal Bond ETF
Prospectus [Line Items]
Average Annual Return, Percent		3.89%			0.68%
Performance Inception Date	Feb. 04, 2021
State Street Nuveen Municipal Bond ETF \| After Taxes on Distributions
Prospectus [Line Items]
Average Annual Return, Percent		3.83%			0.59%
State Street Nuveen Municipal Bond ETF \| After Taxes on Distributions and Sales
Prospectus [Line Items]
Average Annual Return, Percent		3.66%			0.92%