Class I [Member] Class A1 [Member] Class A2 [Member] Alternative Minimum Tax Risk [Member] Below Investment Grade Risk [Member] Common Stock [Member] Call Risk [Member] Credit Spread Risk [Member] Debt Securities Risk [Member] Defaulted or Distressed Securities Risk [Member] Derivatives Risk [Member] Duration Risk [Member] Fair Value Risk [Member] Hedging Risk [Member] Inflation Risk [Member] Insurance Risk [Member] Inverse Floating Rate Securities Risk [Member] Issuer Credit Risk [Member] Municipal Securities Market Risk [Member] Municipal Securities Market Liquidity Risk [Member] Puerto Rico Municipal Securities Market Risk [Member] Reinvestment Risk [Member] Restricted and Illiquid Investments Risk [Member] Reverse Repurchase Agreement Risk [Member] Special Risks Related to Certain Municipal Obligations [Member] Special Situations Municipal Securities Risk [Member] Tax Risk [Member] Taxability Risk [Member] Tender Option Bond Regulatory Risk [Member] Tobacco Settlement Bond Risk [Member] Unrated Investments Risk [Member] Valuation Risk [Member] When- Issued and Delayed Delivery Transactions Risk [Member] Zero Coupon Bonds Risk or Pay-In-Kind Securities Risk [Member] Active Management Risk [Member] Borrowing Risk [Member] Fund Tax Risk [Member] Investment and Market Risk [Member] Large Shareholder Risk [Member] Leverage Risk [Member] Repurchase Offers Risk [Member] Certain Affiliations [Member] Counterparty Risk [Member] Cybersecurity Risk [Member] Deflation Risk [Member] Direct lending risk [Member] Economic and Political Events Risk [Member] Global Economic Risk [Member] Income Risk [Member] Legislation and Regulatory Risk [Member] Litigation Risk [Member] Other Investment Companies Risk [Member] Potential Conflicts of Interest Risk [Member] Recent Market Conditions Risk [Member] Risks Related to the Fund’s Clearing Broker and Central Clearing Counterparty [Member] Preferred Stock [Member] Series A MFP Shares [Member] Series B MFP Shares [Member] Class I. Class A1. Class A2. Municipal Securities Market Risk. Issuer Credit Risk. Credit Spread Risk. Below Investment Grade Risk. Special Situations Municipal Securities Risk. Duration Risk. Call Risk. Reinvestment Risk. Inverse Floating Rate Securities Risk. Municipal Securities Market Liquidity Risk. Restricted and Illiquid Investments Risk. Defaulted or Distressed Securities Risk. Derivatives Risk. Puerto Rico Municipal Securities Market Risk. Special Risks Related to Certain Municipal Obligations. Unrated Investments Risk. Valuation Risk. Hedging Risk. Tax Risk. Alternative Minimum Tax Risk. Reverse Repurchase Agreement Risk. Taxability Risk. Inflation Risk. Insurance Risk. Debt Securities Risk. Tender Option Bond Regulatory Risk. Tobacco Settlement Bond Risk. Investment and Market Risk. Repurchase Offers Risk. Leverage Risk. Borrowing Risk. Large Shareholder Risk. Fund Tax Risk. Series A MFP Shares. Series B MFP Shares. Economic and Political Events Risk. Global Economic Risk. Legislation and Regulatory Risk. Potential Conflicts of Interest Risk. Income Risk. Deflation Risk. Cybersecurity Risk. Litigation Risk. Certain Affiliations. Counterparty Risk. Risks Related to the Fund’s Clearing Broker and Central Clearing Counterparty. Other Investment Companies Risk. Direct lending risk. When- Issued and Delayed Delivery Transactions Risk. Fair Value Risk. Zero Coupon Bonds Risk or Pay-In-Kind Securities Risk. Active Management Risk. Recent Market Conditions Risk.