You should always consult your owner's manual for the most accurate and up-to-date information. It will specify the correct type of oil (e.g., 0W-20, 5W-30) and the amount of oil needed.
Generally, modern Chevy Malibus use synthetic blend or fully synthetic oil, but the specific grade will be in your owner's manual. Don't rely on generic advice; using the incorrect oil can damage your engine.