If it's just a numbers game, then the US has saved orders of magnitude more people than they've killed. Hell, even if you just look at the Bush administration, PEPFAR alone saved more than 26 million people, while the Iraq war killed one million at most.
I mean if this is only about outcome and not about intent, the US has historically provided about 1/3 of the Earth's foreign aid. You could discount that by saying that the US, being so wealthy, was more capable of doing that. But that's not the outcome-oriented viewpoint that we're taking.
We could look at the moral philosophy of the leaders and political systems at play here, but that would be "ignoring the reality", so let's just get out the sparklers and don our American flag shorts, because your by-the-numbers approach has a clear winner! USA! USA! USA!