If the font is installed it is available in InDesign. You can click on the filter button, so it will either show only favorites, or only Typekit fonts.
Arial is not a Typekit font as it is installed on most computer if not all by default.
You can go to the same location as Indesign application. Find the fonts folder and add the font to the indesign Fonts folder.InDesign can almost always see fonts present in the Fonts folder. you can also put an alias (shortcut) to a folder of fonts