Make sure the mail category is selected. In the image below, the Mail tab is circled in red. You can tell the that the mail category is selected because the Mail tab is a lighter blue, while the Calendar tab and Contacts tab are a darker blue. If a tab other than the Mail tab is a lighter blue, click on the Mail tab to select it and make it a lighter blue. Once the Mail tab is a lighter blue, click on the options link in your hotmail account like the options link in the red circle on the far right of the image below.

Click on Mail Display Settings in your account like the link in the red oval in the image below.

In the image above, the setting Message Headers is in a red oval. Change the option from basic like the image above to full like the image below by clicking the option "full" in message headers. Then go down to the bottom of the page and click the OK button in your hotmail account like the OK button in the red circle in the image below.