Why does $1T seem unreasonable? You can check the auction results, and from my quick look at a couple recent auctions, combined with knowledge that the auctions are routine and regularly scheduled, the number seems plausible.
It's not really $1T sold though, $1T would be the net sales, as many bonds and bills would have matured in the same period. Gross sales is much more than $1T, but I'm not going to dig through to find those numbers.
You could maybe discount some of the issuance as internal borrowing/lending/savings, but if you want to treat programs as independent, then the interactions between programs and the general budget are real enough.
It's not really $1T sold though, $1T would be the net sales, as many bonds and bills would have matured in the same period. Gross sales is much more than $1T, but I'm not going to dig through to find those numbers.
You could maybe discount some of the issuance as internal borrowing/lending/savings, but if you want to treat programs as independent, then the interactions between programs and the general budget are real enough.