This excerpt taken from the CVS 10-K filed Feb 27, 2007.
Income taxes ~ The Company provides for federal and state income taxes currently payable, as well as for those deferred because of timing differences between reported income and expenses for financial statement purposes versus tax purposes. Federal and state incentive tax credits are recorded as a reduction of income taxes. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the carrying amount of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Deferred tax assets and liabilities are measured using the enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recoverable or settled. The effect of a change in tax rates is recognized as income or expense in the period of the change.