Shareholder Report, Average Annual Return (Details)	12 Months Ended	60 Months Ended	120 Months Ended
Shareholder Report, Average Annual Return (Details)	May 31, 2025	May 31, 2025	May 31, 2025
C000005984 [Member]
Average Annual Return [Line Items]
Line Graph and Table Measure Name	Institutional Shares
Average Annual Return, Percent	3.41%	7.60%	4.81%
C000005981 [Member]
Average Annual Return [Line Items]
Line Graph and Table Measure Name	Investor A Shares (with sales charge)
Average Annual Return, Percent	(2.28%)	6.18%	3.95%
C000005983 [Member]
Average Annual Return [Line Items]
Line Graph and Table Measure Name	Investor C Shares (with sales charge)
Average Annual Return, Percent	1.32%	6.52%	3.81%
C000198221 [Member]
Average Annual Return [Line Items]
Line Graph and Table Measure Name	Class K Shares
Average Annual Return, Percent	3.42%	7.66%	4.85%
C000101856 [Member]
Average Annual Return [Line Items]
Line Graph and Table Measure Name	Class R Shares
Average Annual Return, Percent	2.88%	7.07%	4.23%
Without Sales Load [Member] \| C000005981 [Member]
Average Annual Return [Line Items]
Line Graph and Table Measure Name	Investor A Shares
Average Annual Return, Percent	3.14%	7.33%	4.51%
Without Sales Load [Member] \| C000005983 [Member]
Average Annual Return [Line Items]
Line Graph and Table Measure Name	Investor C Shares
Average Annual Return, Percent	2.32%	6.52%	3.81%
MSCI ACWI ex USA Index [Member]
Average Annual Return [Line Items]
Line Graph and Table Measure Name	MSCI ACWI ex USA Index
Average Annual Return, Percent	13.75%	10.37%	5.47%