Label

Element

Value

Midcap Stock Portfolio

Risk/Return:

rr_RiskReturnAbstract

Supplement [Text Block]

ck0001056707_SupplementTextBlock

October 16, 2013

DREYFUS INVESTMENT PORTFOLIOS

-MidCap Stock Portfolio

Supplement to Summary and Statutory Prospectuses

dated May 1, 2013

IMPORTANT NOTICE REGARDING CHANGE IN INVESTMENT POLICY

Risk/Return [Heading]

rr_RiskReturnHeading

Midcap Stock Portfolio

Strategy [Heading]

rr_StrategyHeading

The following information is inserted after the first sentence of the first paragraph in the "Principal Investment Strategy" in the Summary prospectus and "Fund Summary - Principal Investment Strategy" in the prospectus and is inserted after the second sentence of the first paragraph and supersedes and replaces the last sentence in the "Fund Details - Goal and Approach" section in the prospectus:

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

“The fund currently considers mid-cap companies to be those companies with market capitalizations that fall within the range of companies in the Standard & Poor’s MidCap 400^® Index, the fund’s benchmark index.  As of September 30, 2013, the market capitalization range of companies in the Standard & Poor's MidCap 400^® Index was between approximately $11.36 billion and $499 million.  The capitalization range varies with market changes and reconstitutions of the index.”