From Swedish translator Matti Jääro: 

The idiom: Det är ingen ko på isen

Literal translation: “There’s no cow on the ice.”

What it means: “There’s no need to worry. We also use ‘Det är ingen fara på taket,’ or ‘There’s no danger on the roof,’ to mean the same thing.” 

The idiom: Att glida in på en räkmacka

Literal translation: “To slide in on a shrimp sandwich.”

What it means: “It refers to somebody who didn’t have to work to get where they are.” 

The idiom: Det föll mellan stolarna

Literal translation: “It fell between chairs.”

What it means: “It’s an excuse you use when two people were supposed to do it, but nobody did. It has evolved into the slightly ironic phrase, ‘It fell between the chair,’ which you use when you want to say, ‘Yeah, I know I was supposed to do it but I forgot.’”