Adobe InDesign Default Fonts
Anything you do without an InDesign doc open, saves to default prefs... To change the default font for an active document, deselect everything (Command/Ctrl-Shift-A) and choose a different typeface from the Control palette (you'll need the Type tool selected) or the Character palette with any tool selected.
From then on, all new text frames you create will default to that face. To make the font the default for new text frames in every document, do the change with no InDesign documents open.
There's tons of stuff you can access in InDesign with no documents open, by the way, such as Text Frame Options and Stroke and Fill settings for the Shape and Line tools. Any change you make gets saved in your application preferences file as the new default for that tool, dialog, or palette field.