Isn’t that what my question was all about in the first place? You mentioned the confessions in a manner that implied they were equivalent to the Magisterium,
No, more comparable to the Catholic Catechism. Though, again, Lutheran polity is not the same as Catholic polity.
I asked how many of the groups that call themselves Lutheran follow them.
No, you asked about Lutheran “denominations”. But be that as it may, there are essentially two views of the confessions among Lutherans: one is a quia subscription, the other a quatenus subscription.
A quia subscription is the acceptance of the doctrines in the confessions are entirely a right reflection of scripture.
A Quatenus subscription is an acceptance of the doctrines in the confessions
insofar as they are a right reflection of scripture.
Where this has caused the most concerning differences is reflective of societal progressivism. By that I mean quatenus subscription Lutherans are open to female clergy while quia subscription Lutherans are not.
Broadly, the two groups are represented by two worldwide organizations: Lutheran World Federation, mainly quatenus subscription synods and International Lutheran Council, primarily quia subscription (Confessional Lutherans).