A quick Google Search reveals the following details.

US life expectancy is as of 2015 78.74 years. This is completely level since 2012.

In 2011, life expectancy was 78.64.

The life expectancy first broke 78 years in 2008.

The google search only has data up until 2015 and around December 2016, there was a flood of stories talking about the life expectancy declining for the first time in 20 years. I suppose the decline is noticed in a rounding error.

Towards the end of December, the information for 2016 might be released.