One thing I think people miss when political donations by company are listed like this is that it's not the company itself making donations, it's their individual employees.
Ever made a political donation? Remember when it asked for your employer on the form? Well this figure is from people who put IBM there on their form.
So when you read a stat like this that tells you one company overwhelmingly donated one way or the other, it's really telling you nothing about the company itself, and more about the employees who work there - primarily the low level employees, who likely vastly outnumber everyone else.
Similarly, it means nothing as far as corruption is concerned when you look into a specific candidate's political donations and see that, for example, oil companies overwhelmingly donated to them. It doesn't mean oil companies literally donated to them, it means people who work at oil companies did.
It might be useful for gauging a company's general culture, but even then I'd be cautious since the bulk of political donations for most companies is probably dominated by their low level employees.