From the BLS:
The Consumer Price Index for All Urban Consumers (CPI-U) declined 0.4 percent in December on a seasonally adjusted basis, the U.S. Bureau of Labor Statistics reported today. Over the last 12 months, the all items index increased 0.8 percent before seasonal adjustment.
The gasoline index continued to fall sharply, declining 9.4 percent and leading to the decrease in the seasonally adjusted all items index. The fuel oil index also fell sharply, and the energy index posted its largest one-month decline since December 2008, although the indexes for natural gas and for electricity both increased. The food index, in contrast, rose 0.3 percent, its largest increase since September.
The index for all items less food and energy was unchanged in December, following a 0.2 percent increase in October and a 0.1 percent rise in November. This was only the second time since 2010 that it did not increase.
emphasis added
I’ll post a graph later today after the Cleveland Fed releases the median and trimmed-mean CPI. This was at the consensus forecast of a 0.4% decrease for CPI, and below the forecast of a 0.1% increase in core CPI.