"I'm so comfortable here now," the 26-year-old Johnson said during a news conference Wednesday. "At first, not at all, but being here for five years, being around these people here in Detroit, teammates and just the city -- I'm just growing accustomed to it."
Johnson's agent, Bus Cook, said the contract is worth $60 million guaranteed.
"Calvin's one of those guys -- we've said this about a few guys that we have in our building -- whatever they pay him is not enough," Lions coach Jim Schwartz said. "He's truly a special player."