The 51-year-old actress discussed motherhood in the May issue of Vanity Fair and how she is raising Sunday and Faith, her 10- and 8-year-old daughters with Urban, to be religious.
"That's how we are raising our children. Keith has his own beliefs but he comes, too," she said of Urban, whom she married in June 2006.
Kidman said "a lot" of her friends tease her for her beliefs but voiced her strong faith in God.
"I had a very Catholic grandmother, and I was raised praying, so that had massive impact. I wouldn't say it's absolutism, there's constant questioning -- I'm a willful, feisty girl," the star said.
"For me it's very important that I don't have judgment. My dad would always say, 'Tolerance is the most important thing,'" she added.
In addition, Kidman tries "to keep some sort of boundaries" for Sunday and Faith by not allowing them to have cellphones or Instagram accounts. She said Sunday shares her interest in acting, although she and Urban allow their daughters to explore their interests at their own pace.
"You can't really get kids into anything, I've realized. You can push them a bit, but motivation is a really hard thing. I mean, nobody motivated me to be an actor; if anything they tried to deter me," the actress said.
Kidman is also parent to 26-year-old daughter Isabella and 24-year-old son Connor with ex-husband Tom Cruise. Isabella is married and resides in London, while Connor is pursuing music and living in Miami.
"Bella lives just outside London. You know, she really feels more English. We lived there for Eyes Wide Shut, Mission Impossible and The Portrait of a Lady," Kidman said. "They both had English accents when they were little."
Kidman previously discussed her religious beliefs in in the December/January issue of Allure. She told the magazine she "loved the idea" of becoming a nun, although she chose a different path.