While that's a big number, the report from the official budget scorekeeper for Congress also put the administration's recent move within a wider perspective. Overall, the delay for employers and other changes will raise the cost of the expanding coverage for the uninsured by less than 1 percent over 10 years from the budget agency's previous estimate in May, CBO said.

The White House announced earlier this month that it would delay a requirement for employers with 50 or more workers to offer affordable coverage, or face fines. Instead of going into effect next year, the provision was put off to 2015. A major concession to business groups, the delay took administration allies and adversaries by surprise.

Opponents of the health care law saw the delay as a sign that the implementation of the measure had run into serious problems, and some labor unions denounced it as a handout to big business. But employers welcomed the unexpected respite from complicated reporting rules that the administration concedes will require more time to work out. The White House says the rest of the law's provisions will roll out without delay.