I have  a problem with transactions and I hope you can help me.

On 9.11.13 I sent only 10BTC from my computer qt wallet
 
https://blockchain.info/address/1BhNBZewXWZbQRhLZJkJtc4qMusyo1LZfs

to online wallet in blockchain

https://blockchain.info/address/19szGM9SeVapfrBTMzNUok8zGq5mPXL8RV,

here is my qt wallet actions list
(i am not talking here about the first transaction on the list on 10/12, only on the second one at 9/11 that shows -10 in red)
https://dl.dropboxusercontent.com/u/76795332/BITCOIN.JPG

but now I see that it also sent 21.675 BTC to another adress, I see it in transaction

https://blockchain.info/tx/3e598c50f322ba943879b1e51c5c44faaabe93d85593712234afd170db9018ac ,



but I can't see it on my computer wallet and I didn't send anything to this adress.

so what is the 21.675 BTC about?