Portfolio Building Block 1X Inverse Developed Markets Ex US Daily Target ETF Underlying ETF Price Appreciation Risk [Member] Indirect Investment in Underlying ETF Risk [Member] Underlying ETF Good Performance Risk [Member] Large-, Mid- and Small-Cap Developed Markets Ex United States Outperformance Risk [Member] Single Issuer Risk [Member] Compounding and Market Volatility Risk [Member] Daily Correlation/Tracking Risk [Member] Short Sale Exposure Risk [Member] Derivatives Risk [Member] Swap Agreements [Member] Options Contracts [Member] Futures Contracts [Member] Counterparty Risk [Member] Intra-Day Investment Risk [Member] Fixed Income Securities Risk [Member] Rebalancing Risk [Member] Concentration Risk [Member] Economic and Market Risk [Member] ETF Risks [Member] Authorized Participants, Market Makers, and Liquidity Providers Concentration Risk [Member] Cash Redemption Risk [Member] Costs of Buying or Selling Shares [Member] Shares May Trade at Prices Other Than NAV [Member] Trading [Member] Liquidity Risk [Member] High Portfolio Turnover Risk [Member] Tracking Error Risk [Member] Liquidity Risks [Member] Management Risk [Member] Money Market Instrument Risk [Member] New Fund Risk [Member] Operational Risk [Member] Tax Risk [Member] U.S. Government and U.S. Agency Obligations Risk [Member] Portfolio Building Block 1X Inverse US Value Daily Target ETF Index Price Appreciation Risk [Member] Index Good Performance Risk [Member] Sector Positive Performance Risk (Financial Services, Industrials, Consumer Cyclical, Energy, and Materials) [Member] Large-Cap Outperformance Risk [Member] Portfolio Building Block 1X Inverse US Large Cap Daily Target ETF Large-Cap Stock Outperformance Risk [Member] Portfolio Building Block 1X Inverse US Growth Daily Target ETF Exclusion of Financial Companies Risk [Member] Portfolio Building Block 1X Inverse Developed Markets Ex US Daily Target ETF [Member] Portfolio Building Block 1X Inverse US Value Daily Target ETF [Member] Portfolio Building Block 1X Inverse US Large Cap Daily Target ETF [Member] Portfolio Building Block 1X Inverse US Growth Daily Target ETF [Member] Portfolio Building Block 1X Inverse Developed Markets Ex US Daily Target ETF. Portfolio Building Block 1X Inverse Developed Markets Ex US Daily Target ETF [Member] Portfolio Building Block 1X Inverse US Value Daily Target ETF. Portfolio Building Block 1X Inverse US Value Daily Target ETF [Member] Portfolio Building Block 1X Inverse US Large Cap Daily Target ETF. Portfolio Building Block 1X Inverse US Large Cap Daily Target ETF [Member] Portfolio Building Block 1X Inverse US Growth Daily Target ETF. Portfolio Building Block 1X Inverse US Growth Daily Target ETF [Member] Tax Risk. U.S. Government and U.S. Agency Obligations Risk. Operational Risk. New Fund Risk. Money Market Instrument Risk. Management Risk. Liquidity Risk. Tracking Error Risk. High Portfolio Turnover Risk. Trading. Shares May Trade at Prices Other Than NAV. Costs of Buying or Selling Shares. Cash Redemption Risk. Authorized Participants, Market Makers, and Liquidity Providers Concentration Risk. Economic and Market Risk. Concentration Risk. Rebalancing Risk. Fixed Income Securities Risk. Intra-Day Investment Risk. Counterparty Risk. Futures Contracts. Options Contracts. Swap Agreements. Derivatives Risk. Short Sale Exposure Risk. Daily Correlation/Tracking Risk. Compounding and Market Volatility Risk. Exclusion of Financial Companies Risk. Large-Cap Stock Outperformance Risk. Underlying ETF Good Performance Risk. Indirect Investment in Underlying ETF Risk. Underlying ETF Price Appreciation Risk. ETF Risks. Index Good Performance Risk. Index Price Appreciation Risk. Large-Cap Outperformance Risk. Sector Positive Performance Risk (Financial Services, Industrials, Consumer Cyclical, Energy, and Materials). Single Issuer Risk. Large-, Mid- and Small-Cap Developed Markets Ex United States Outperformance Risk. Liquidity Risks.