document: Shares in Chevron fell 1.1% and Exxon Mobil dropped 0.7% as oil prices fell almost 4% on worries that producers will fail to agree production limits.
  Brent crude fell $1.74 to $46.50 a barrel, while US crude was down $1.79 to $45.29 a barrel.
  The Dow Jones fell 23.7 points to 19,121.60, while the broader S&P 500 index was barely changed at 2,201.72.
  The tech-focused Nasdaq index rose 11.11 points to 5,379.92.
  Earlier, official figures had indicated that the US economy grew faster than previously estimated in the third quarter of the year.
  The economy grew at an annualised rate of 3.2%, the Commerce Department said, compared with an initial estimate of 2.9%.
summary: US stock markets closed little changed, but energy shares fell as the oil price slid ahead of Wednesday's Opec meeting.