The health care law will cut the deficit by $109 billion over the next decade and is $84 billion cheaper after a Supreme Court ruling gave states more flexibility to nix an expansion to Medicaid, the Congressional Budget Office said today.

The nonpartisan CBO updated its cost estimates for the health care law, and the estimates cheered Democrats, who have sparred repeatedly with Republicans over whether the law cuts or adds to the deficit.

The CBO predicted that 3 million fewer people will have health insurance under the law in 2022 after the high court’s decision. Repealing it would double the number of people without health insurance from 30 million to 60 million, the CBO projected.

The office projected that 6 million fewer people will sign up for Medicaid and 3 million more will sign up for federally subsidized insurance exchanges. The exchange subsidies cost the government about $9,000 a year versus $6,000 for Medicaid, the CBO said. On net, however, the government will save money because fewer people would be getting subsidized at all.

Senate Majority Leader Harry Reid (D-Nev.), checking his BlackBerry for the results at his press conference, said the reduction in the deficit backs up what Democrats have been saying since the law was enacted in 2010.