She usually doesn't, but there have been a few times she lipsynched to the backing track for the entire song.
Lana, Kelly, Adele, and Pink never have, but that's all I can think of.
You can hear her voice in almost every one of those clips. She is guilty of having heavy backtrack sometimes on tour though and occasionally getting kinda quiet with her vocals, but she's never flat-out lip-synced.
Almost no one sings 100% live, 100% of the times. Even Whitney lip-synced during her prime from time to time. Mariah and Celine lip-sync a lot. Bey lips/uses a backing track for her uptempo songs. Christina has lipped while on tour (Slow Down Baby was pre-recorded as well as some notes in Ain't No Other Man / Candyman) and some live TV performances (Stripped era being the worst offender), but she doesn't lip much anymore (well, she lips the Candyman E5, I don't remember the last time she sang it live, maybe in 2006).
Leona lipped like twice in her whole career... so really good for her. Gaga also lipped some uptempo songs. Kelly Clarkson as far as I know doesn't lip-sync but never say never. Adele also I don't think lips, but her songs are really not that difficult and she barely moves on stage, so there's no excuse (well, unless your name is Britney).
Pretty sure every artist has lip-synced at least once. I only say this because sometimes on shows (like Today, GMA, those kind of things...) they require you to lip sync.