N R [Member] Commercial Services And Supplies [Member] Tobacco [Member] Health [Member] Corporate Sector [Member] Housing [Member] Education [Member] State [Member] County City Special District School District [Member] C000199771 [Member] Class K C000038359 [Member] Investor C C000011313 [Member] Investor A1 C000038358 [Member] Investor A C000011316 [Member] Institutional Transportation Sector [Member] Standard & Poor's, B Rating [Member] Standard & Poor's, BB Rating [Member] Standard & Poor's, BBB Rating [Member] Standard & Poor's, A Rating [Member] Standard & Poor's, AA Rating [Member] Standard & Poor's, AAA Rating [Member] Investment Type [Axis] Net Assets Investment Company Portfolio Turnover No Trading Symbol Flag