Warren Buffett bet $600 million on Gillette - and ended up owning Duracell. Here's how his razor wager led to him buying the battery titan.

• Warren Buffett's Berkshire Hathaway built a $600 million position in Gillette in 1989.
  
• The investor's company swapped its stake for over $4 billion of Procter & Gamble stock in 2005.
• Buffett used P&G shares and some cash to buy Duracell in 2014.

Warren Buffett turned $600 million into over $4 billion by betting on Gillette, then parlayed his stake in the shaving specialist into acquiring Duracell. Here's the story of how the famed investor's razor wager led to him buying the battery maker.