Designers craft and edit graphic designs in a layer representation, but layer-based editing becomes impossible once composited into a raster image.In this work, we propose LayerD, a method to decompose raster graphic designs into layers for re-editable creative workflow.LayerD addresses the decomposition task by iteratively extracting unoccluded foreground layers and completing the background.We propose a simple yet effective refinement approach taking advantage of the assumption that layers often exhibit uniform appearance in graphic designs.As decomposition is ill-posed and ground-truth layer structure may not be reliable, we develop a metric that measures the quality of the decomposition.In experiments, we show that LayerD successfully achieves high quality decomposition and outperforms baselines.We also demonstrate the use of LayerD with state-of-the-art image generators and layer-based editing.