Actually that's an exaggeration. It's only a little more than $900 million:

The United States plans to pledge more than $900 million to help rebuild Gaza after Israel's offensive against Hamas and strengthen the Palestinian Authority, a U.S. official said on Monday. The money will be channeled through UN and other bodies and will not be distributed via the militant group Hamas, which rules Gaza, said the official, who spoke on condition of anonymity as U.S. Secretary of State Hillary Clinton plans to make the announcement next week at a Gaza donors conference in Egypt. The March 2 donors conference in Sharm el-Sheikh resort aims to raise humanitarian and rebuilding funds for Gaza after Israel's offensive against Hamas at the end of last year. About 1,300 Palestinians were killed during the campaign, according to Gaza officials, as were 13 Israelis.

Old Reuters boilerplate: "About 1,300 Palestinians were killed during the campaign, about two-thirds of which were civilians..."

New Reuters boilerplate: "About 1,300 Palestinians were killed during the campaign, according to Gaza officials..."

And people say that there's no upshot to thoroughly debunking the credulous pro-Hamas propaganda published by Western media outlets. Look how much more straightforward and honest they're being!

Anyway, one billion US dollars are going to UNRWA for infrastructure. I would point out that this is effectively a backdoor subsidy for Hamas since normally they'd have to spend some of their money being effective civil administrators. This way they can use all their resources for weapons and war-fighting. But since the money is going to UNRWA it's actually a direct subsidy for Hamas.

References:
* 'U.S. plans to pledge $900 million for Gaza' [Ha'aretz]
* Gaza Body Count: Were We Duped? [TIME]
* Obligatory Post About Kerry Being Shocked Shocked That UNRWA Works For Hamas [MR]

Previously:
* UN: "Clerical Error" Made Us Mistakenly Think Israel Bombed UNRWA School. Opps.
* UN Imposes Collective Punishment On Gaza Population In Response To Hamas Crimes, Suspends Humanitarian Shipments
* Congress: Hey, Has Anyone Heard About This "We Fund UNRWA And UNRWA Funds Hamas" Rumor?