Label	Element	Value
Global Strategist Portfolio
Risk/Return:	rr_RiskReturnAbstract
Supplement [Text Block]	ck0000741375_SupplementTextBlock	Summary Prospectus and Prospectus Supplement May 2, 2017 Morgan Stanley Institutional Fund Trust Supplement dated May 2, 2017 to the Morgan Stanley Institutional Fund Trust Summary Prospectus and Prospectus dated May 1, 2017 Global Strategist Portfolio
Risk/Return [Heading]	rr_RiskReturnHeading	Global Strategist Portfolio
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The composition of the Customized MSIM Global Allocation Index, the secondary benchmark index of the Global Strategist Portfolio, has been changed from 60% MSCI All Country World Index, 30% Bloomberg Barclays Global Aggregate Bond Index, 5% S&P GSCI Light Energy Index and 5% Bank of America/Merrill Lynch U.S. Dollar 1-Month LIBID Average Index to 60% MSCI All Country World Index and 40% Bloomberg Barclays Global Aggregate Bond Index, effective May 31, 2017. Please retain this supplement for future reference.
Performance Additional Market Index [Text]	rr_PerformanceAdditionalMarketIndex	The composition of the Customized MSIM Global Allocation Index, the secondary benchmark index of the Global Strategist Portfolio, has been changed from 60% MSCI All Country World Index, 30% Bloomberg Barclays Global Aggregate Bond Index, 5% S&P GSCI Light Energy Index and 5% Bank of America/Merrill Lynch U.S. Dollar 1-Month LIBID Average Index to 60% MSCI All Country World Index and 40% Bloomberg Barclays Global Aggregate Bond Index, effective May 31, 2017.

rr_RiskReturnAbstract

rr_RiskReturnHeading

Global Strategist Portfolio

Performance Additional Market Index [Text]

rr_PerformanceAdditionalMarketIndex

The composition of the Customized MSIM Global Allocation Index, the secondary benchmark index of the Global Strategist Portfolio, has been changed from 60% MSCI All Country World Index, 30% Bloomberg Barclays Global Aggregate Bond Index, 5% S&P GSCI Light Energy Index and 5% Bank of America/Merrill Lynch U.S. Dollar 1-Month LIBID Average Index to 60% MSCI All Country World Index and 40% Bloomberg Barclays Global Aggregate Bond Index, effective May 31, 2017.