WASHINGTON — Executives of five of the largest oil companies on Thursday defended the $2.1 billion they receive each year in tax breaks, but said they would be willing to give them up as part of a comprehensive reform of the tax code.

At a three-hour Senate Finance Committee hearing that was largely political theater interrupted occasionally by a serious tax policy discussion, the oil industry executives said their current tax breaks were not subsidies but legitimate tax deductions, shared in some cases with other industries.

Rex W. Tillerson, chief executive of Exxon Mobil, said that the provisions, such as a tax deduction for certain types of manufacturing, were not “special incentives, preferences or subsidies for oil and gas, but rather standard deductions applied across all businesses in the United States.”

He said that eliminating the provision just for the oil industry would be “misinformed and discriminatory.”