As good a summary of the specifics as I have run across.....
On December 30, 2013, Michigan obtained approval from the Centers for Medicare and Medicaid Services (CMS) to amend its § 1115 demonstration waiver, “Healthy Michigan”, to implement the Affordable Care Act’s (ACA) Medicaid expansion. Beginning April 1, 2014, the waiver and associated state plan amendments will provide Medicaid coverage to all adults in Michigan with incomes up to and including 138% of the Federal Poverty Level (FPL) (about $32,500 for a family of four in 2013) — an estimated 300,000 to 500,000 adults.1 More specifically, when implemented on April 1, 2014, the Michigan waiver will: