The Obama administration said Wednesday that it had granted broad waivers to four states allowing health insurance companies to continue offering less generous benefits than they would otherwise be required to provide this year under the new federal health care law. The states are Florida, New Jersey, Ohio and Tennessee, the administration told Congress. Lawmakers said that many other states, insurers and employers needed similar exemptions from some of the law's requirements and would seek waivers if they knew of the option. Steven B. Larsen, a top federal insurance regulator, said the waivers would allow many consumers to keep the coverage they had, a goal often espoused by President Obama.