That's probably a record for the 330. I think the longest flight until now on any 330 was about 10,500 on a delivery flight from TLS to MEL. DL might have routed this recent flight a little indirectly to get the record.
In terms of DL fights, I don't think any 747 has ever gone that far. A 787 will do over 12k miles empty, but DL doesn't have any. A 772-LR however can do over 13k miles and DL has 10 of these so there a possibility of a similar DL ferry flight from SIN>to US East Coast or JNB to SEA that might have gone farther.
Aircraft can go a lot farther on a ferry flight with no load.