Nuveen Impact Bond ETF S000108508 [Member] C000279503 [Member] Call Risk [Member] Cash Redemption Risk [Member] Counterparty Risk [Member] Credit Risks [Member] Credit Spread Risk [Member] Currency Risk [Member] Cybersecurity Risk [Member] Derivatives Risks [Member] Dollar Roll Transaction Risk [Member] Emerging Markets Risk [Member] Floating and Variable Rate Securities Risk [Member] Foreign Investment Risk [Member] High Yield Securities Risk [Member] Illiquid Investments Risk [Member] Impact Strategy Risk [Member] Income Risk [Member] Interest Rate Risks [Member] Market Risks [Member] Market Liquidity Risk [Member] Market Trading Risks [Member] Mortgage and Asset Backed Securities Risk [Member] Regulation S Securities Risk [Member] Prepayment Risks [Member] Service Provider Operational Risk [Member] TEFRA Bond Subsidiary Risk [Member] Unrated Security Risk [Member] U S Government Securities Risk [Member] Valuation Risk [Member] Wholly Owned Subsidiary Risk [Member] Active Management Risk [Member]