I disagree with the company/individual distinction premise but even if you ignore individual contributions it's fairly even. Doesn't seem like a distinctly partisan issue.
> Would you also disagree with a company/labor union distinction?
Labor unions are corporations, and corporations will fight for the corporation's interests. Those interests may align with the interests of their shareholders, but they may not always.
Note that I'm talking about money from companies (most to Republicans) not the individuals that work for them (most to Democrats).