In addition to the risks posed in other answers, there is a very real risk of identity theft related to publishing your exact financial details. In a broader sense, any time something is assumed private but you've made it public, you risk losing the advantage of other people assuming those details are private.
For example, credit bureaus will sometimes take additional steps to verify your identity if certain conditions are true. One of the ways they do this is by asking about financial transactions that they would expect to be private. For instance, they may ask, "how much was the monthly payment for the mortgage you had on your house three years ago?" Generally they accept answers that are close, but not exact.
Obviously, if you publish transactional details like "I spent 1,036.14 on my mortgage this month" you are putting yourself at risk for people using that information to steal your identity.