Get result from async method

I have this method in my service:

public virtual async Task<User> FindByIdAsync(string userId)
{
    this.ThrowIfDisposed();
    if (userId == null)
    {
        throw new ArgumentNullException("userId");
    }
    return await this.repository.FindByIdAsync(userId);
}

and then in a view I have this code:

using (var service = new UserService(new CompanyService(), User.Identity.GetUserId()))
{
    var user = service.FindByIdAsync(id);
}

but the user is the Task and not the User. I tried adding await to the service call, but I can't use await unless the current method is async. How can I access the User class?