A phosphorus-free automatic dishwashing detergent composition comprising 2.5 to 8 wt % of a first polymer comprising polymerized units of: (i) 55 to 85 wt % of a C3-C6 monoethylenically unsaturated carboxylic acid, (ii) 2 to 30 wt % of a C3-C6 monoethylenically unsaturated dicarboxylic acid and (iii) 2 to 15 wt % of a C5-C12 monoethylenically unsaturated tertiary amine; and having Mw from 2,000 to 100,000.