How to deal with UTCTime?

What's the best way to deal with UTCTime? I tried deriving the Elm definition and here's what showed-up on the Elm side:

```
type alias UTCTime =
{ utctDay: Day
, utctDayTime: DiffTime
}

jsonDecUTCTime : Json.Decode.Decoder ( UTCTime )
jsonDecUTCTime =
("utctDay" := jsonDecDay) >>= \putctDay ->
("utctDayTime" := jsonDecDiffTime) >>= \putctDayTime ->
Json.Decode.succeed {utctDay = putctDay, utctDayTime = putctDayTime}

jsonEncUTCTime : UTCTime -> Value
jsonEncUTCTime val =
Json.Encode.object
[ ("utctDay", jsonEncDay val.utctDay)
, ("utctDayTime", jsonEncDiffTime val.utctDayTime)
]
```

Is this the idiomatic way of dealing with timestamps on the Elm side? (I'm new to Elm, so please pardon this newbie question). If not, then how does one specify some sort of "mapping" between an idiomatic Haskell type and its corresponding idiomatic Elm counterpart?