IDEA Full Funding Act - Amends the Individuals with Disabilities Education Act (IDEA) to reauthorize and make appropriations for the grant program to assist states and outlying areas to provide special education and related services to children with disabilities. Decreases the amount authorized and makes appropriations for FY2010-FY2011, authorizes and makes specified appropriations for FY2012-FY2017, and sets forth a formula for determining the authorization of, and makes, appropriations for FY2018 and thereafter.