This Google Apps script imports time entries from Toggl.com into a Google Sheet using their Detailed Report API.
For a given month it displays in a sheet all your tasks. [Date - Who - Hours - Description]
Open this Google Sheet and make a copy in your Google Drive account.
Create a new Google Sheet.
Create a new script in your newly created Google Sheet and paste the contents of the files Code.gs, Dates.gs and Toggl.gs in their respective script files.
Edit Toggl.gs to fill in your workspace_id and api_token.
To figure out your workspace_id: go to Team in toggl.com. The number at the end of the URL is the workspace id.
To figure out your api_token: go to your Profile in toggl.com, your API token is at the bottom of the page.
After a reopen of your Google Sheet you will have a new menu open called "Toggl" with a sub-menu "Get Timesheet for Month".
Fill a date of the month you want to import in cell B1. So if you want your timesheet for December 2016, fill the date 01/12/2016 and click Toggl > Get Timesheet for Month.
Credits go to koen-github which provided an example on how to use the Toggl API with Google Sheet.