That's the reinvested capital earned by BHE, not from the parent BRK. Right?

Both, I think. But I've never tried to track it.
I guess BHE has its own filings, so one could figure it out.

[we pause briefly while Jim has a peek for the first time]

I had assumed some of the larger acquisitions would not have been done with just debt and retained earnings, especially the earlier ones: money from Omaha would have been needed.

But maybe you're right...the filings show only $6bn of paid in capital, versus $42bn in retained earnings, comprising effectively the whole of shareholders' equity.
Maybe the funding from Berkshire that I had imagined was (if it existed) limited to loans, perhaps only bridge financing since Berkshire is clear on the fact that the debt is non-recourse.
I couldn't find any mention of notes payable up the chain, but the filing is 569 pages.

Jim