B777 Captain reported the left engine Integrated Drive Generator failed in cruise due to an oil leak. Flight crew diverted and landed safely.

Narrative

Upon arriving at flight planning; we were made aware of an inbound electric generator drive left write up. Our dispatcher had asked maintenance to fix it rather than the deferral they wanted as the fuel penalty to run the APU the entire flight was too great for our maximum taxi weight. We kept ourselves aware of the progress and understand they felt they had fixed it and were 'confirming' with a 20 minute engine runup . The Maintenance Release was cleared. We arrived at the cockpit to find the Maintenance Release had no explanation as to what was wrong with the generator or ultimate IDG (Integrated Drive Generator) auto disconnect due to over temp nor what they had done. I called maintenance and requested info. Person A at Maintenance Control said they added oil. I requested Mx (Maintenance) come to the cockpit for a clear understanding ; as adding oil to a contained reservoir in IDG was suspicious to me. Where was the leak. Person B appeared; not the person that added the oil or had eyes on the possible leak..he was unreachable within 30 minutes. Person B said he only did the runup from the cockpit and knew they had added oil. I asked how much? How much does reservoir hold? He said he didn't know either answer as they just hit a fill line. Well; enough was lost to cause an over-temperature auto disconnect. Later 2 quarts addition was tossed about. Maintenance was happy with the integrity of the generator and the fact they had fixed any reason the IDG disconnected for us to take it to ZZZZ an almost XX hour flight. Knowing if it failed operating the APU would be necessary to protect the operating right generator. I asked if the Maintenance Release repairs could include full sentences that we could understand as it is our source of communication. We asked if this is then in fact a normal procedure to add oil to the IDG . Person B replied yes; that exhaust can take oil with it and the service check that once had IDG oil check had since removed the check; perhaps in the interest of cost savings? I had to take his word we would have an uneventful flight pertaining to this maintenance issue with the aircraft----as this falls in Company Maintenance licenses/profession. We had to be confident they performed the best maintenance in aviation. Approximately 2 1/2 hours later; apparently the 2 quarts had again ; also leaked out and we lost the left generator and with increasing temperature the left IDG auto disconnected. There was no alarm electrically as the 777 super redundancy carried the load across the bus tie. We pulled up the checklist and manually pushed the IDG disconnect switch with next item calling for the APU start if available; I called dispatch to get some fuel burn numbers. Dispatcher was still on duty and tried to reach out when we asked once again to speak to maintenance. She was somewhat held up as her resources were again unavailable; like mx at the gate. Person B at Maintenance Control again was on the line; without any new direction; I asked for a supervisor as I had learned as much as possible from Person B and it wasn't enough; Person B dropped off the line without a supervisor picking it up. I asked for the 777 systems expert to learn more and a 320 person jumped on the line saying he couldn't help he was 320; Now we are delaying APU start until Dispatch and Operations did the math and confirm we can continue. We keep flying; flying ; She is looking for Chief Pilot; I heard Person C or Person D mentioned. Neither ever got on the line.. so; Person E; a-320 specialist; nor 2 Chief Pilots available. I understand there was a going away party happening in Operations for the Dispatcher leaving the Chief Pilot desk after nearly a decade or so. Sad situation for a Company passenger flight if the event were in fact an emergency. The infrastructure is failing. Our skeletal operation will eventually bite us in the name of cost savings I suppose. We were asked to wait 10 minutes or so. But plan to possibly divert to ZZZ. I reiterated we will fly wherever they want us but the APU is coming on. Dispatch was not happy with fuel penalty continuing to ZZZZ---they were doing the math. A later conversation had Operations/Dispatch bringing up a fuel stop in ZZZ1. I shared my feelings that I was comfortable to keep flying but did not think it prudent to take it back in the air across the ocean once on the ground.....they returned with ZZZ as Pax (Passengers) can continue. We concurred and asked for reroute from Location A. We later requested fuel dump just outside of ZZZ2. We noticed they had the aircraft continuing after ZZZ to ZZZZ. I messaged dispatch that there was a possibility the next crew would refuse the aircraft and she replied they had a back up plane if that is the case. The crew in ZZZ did refuse the aircraft ending in XX. I again reiterated that I would fly as far as I could we had sound electrics. 4-5 maintenance technicians met us in the cockpit and immediately said it was a bad generator and it took the IDG with it. He said he also had a hunch the flight crew would not take it over the ocean but would do what they could. I heard later inquiring with maintenance back in ZZZ3 that the plane stayed in service domestically for 4-5 more days at that time burning the APU coast to coast as the IDG was leaking like a sieve. Too costly to put in Maintenance off the line for a new generator. This is not the airline of 30 years ago. Passing along maintenance for days. Another day all chillers out in aft galley. Maintenance wouldn't come unless I refused airplane. So I did. 8 days flying 14 hour flights with breakfast meat relying on inefficient dry ice. Chillers scheduled to be fixed in 3 more days(2 weeks total) when passing through ZZZ4. After refusal Mx comes on flips switch and gets 2 chillers back. 10 min. arrived at ZZZZ early. Summary; we were team players but we need a team.