Class K [Member] Expense Example - Class K - BlackRock California Municipal Opportunities Fund - Class K	May 31, 2026 USD ($)
Prospectus [Line Items]
Expense Example, with Redemption, 1 Year	$ 41
Expense Example, with Redemption, 3 Years	142
Expense Example, with Redemption, 5 Years	252
Expense Example, with Redemption, 10 Years	$ 573

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