Last I heard it was coming 'Mid-year 2015' - this announcement was made back in September 2014 - http://www.phonearena.com/news/Verizons-Shammo-Expect-Wi-Fi-calling-in-2015_id60880
Also, I find Fran Shammo's hand-waving of Wifi calling an very arrogant/weak argument - there are locations in buildings, in basements, that will never receive a cellular signal. Many people face this on a daily basis. Well maintained wifi is a reality in many business settings, and Verizon customers in these situations would benefit greatly from having wifi calling available.
When will Verizon customers have access to Wifi calling in 2015?