How can I get a general ledger detail report for a single selected account, showng all postings and a total of the debits and credits for the selected period ?

We can customise the report to view the information you need, krajeski.

Here are the steps:

1. On the left panel, click Reports.
2. Type General Ledger in the search box.
3. Select the Report period, and click the Customise button.
4. Click Rows/Columns to expand, and select Change columns.
5. Put a check mark on Debit and Credit boxes.
6. Click the Filter drop-down list.
7. Select the account you want to view from the Account drop-down list.
8. Click Run Report.

For reference, you can check this article: How to customise reports.

Moving forward, if you want to save the report, you can click the Save Customisation button to memorise it. Here's an article for more information: How to memorise reports.

We are always here if you need more help with QuickBooks reports. Thanks.