Nati Harnik/AP
- Warren Buffett's impending departure has fueled a 12% plunge in Berkshire Hathaway stock since May.
- Buffett has built a record cash pile as he's pared Apple and struggled to find bargains.
- Successor Greg Abel could have close to $400 billion in dry powder when he takes over.
Warren Buffett is finding out just how much he's worth to Berkshire



