Someone sends you some BTC.

Can you find out the sender's address and the BTC balance?

I looked at the transaction ID and details but I cannot find the sender's address.

Is it possible to find this information? I know it is easy to see the balance of a certain BTC address but how to find that address?

I should probably mention that we actually did this transaction for this specific reason, to show each other our balance, but we do not know how to see the sender's address. Of course the person could just tell me the wallet address he sent it from but how to verify it is really that address?

Thanks