But, when we edit the page layout, there is no option to remove Probability from page layout. Hide mouse over the field in edit page layout, you will not see minus icon next to it.
This is the same for another few fields in Opportunity:
- Opportunity Name
- Account Name
- Close Date
- Probability (%)
If you notice, there is a blue dot at the front of the field name when you edit page layout. You cannot hide all fields with blue dot in page layout.
You can hide it from Field-Level Security:
- Setup | Customize | Opportunity
- Look for Probability (%) and click the field name
- Click 'Set Field-Level Security' button
- Untick Visibility checkbox for profile do not want to see this field
- Save and done
Since we are hiding the field in field-level, user will not able to see it anywhere, include in report, or in scenario you have many record type and page layout, user will not able to see it in other page layout as well.