You can find the most detailed available information about 1 on 1s held by navigating to Insights -> Managers -> Reports -> 1 on 1 Details.

Filter the data by any time frame you'd like to see in the top right of the report. Then download the data into a spreadsheet to see all the details of those 1 on 1 meetings in the bottom right corner. Results are automatically filtered to show 1 on 1s by you, or those downstream from you in your organization (such as direct reports and skip level reports).