Paid-in capital in excess of par value
When a company sells shares, the money it receives from investors, minus the par value, is credited to an account named capital in excess of par value (or "additional paid-in capital"). In many cases, paid-in capital is not broken out on the balance sheet into two separate line items for the par value and the capital in excess of par value.
One last point on paid-in capital: Some companies issue preferred stock, too, which is also equity and, as such, must figure under stockholders' equity. Furthermore, many companies have multiple share classes and will provide information on each one (even if they provide only a single balance sheet value for "Common stock.")