Other Assets and Liabilities Net [Member] C000096110 [Member] Institutional Plus Shares C000007781 [Member] Institutional Shares C000007780 [Member] Admiral Shares C000007782 [Member] ETF Shares C000007779 [Member] Investor Shares Real Estate Sector [Member] Healthcare Sector [Member] Financial Services Sector [Member] Energy Sector [Member] Technology Sector [Member] C000007791 [Member] C000007794 [Member] C000007792 [Member] C000007793 [Member] C000096111 [Member] Basic Materials [Member] Telecommunications [Member] C000096112 [Member] C000007797 [Member] C000007796 [Member] C000007798 [Member] C000007795 [Member] C000007799 [Member] C000007801 [Member] C000105304 [Member] C000007800 [Member] C000007803 [Member] C000105305 [Member] C000007804 [Member] C000007802 [Member] C000007805 [Member] C000007808 [Member] C000007806 [Member] C000007807 [Member] C000155407 [Member] C000170276 [Member] Institutional Select Shares C000105306 [Member] C000034428 [Member] C000034427 [Member] C000034429 [Member] C000034430 [Member] C000105307 [Member] Investment Type [Axis] Net Assets Investment Company Portfolio Turnover No Trading Symbol Flag