For long-lived assets used in operations, impairment losses are only recorded if the
assets carrying amount is not recoverable through its undiscounted, probability-weighted future cash flows. We measure the impairment loss based on the difference between the carrying amount and estimated fair value. Long-lived assets are
considered held for sale when certain criteria are met, including when management has committed to a plan to sell the asset, the asset is available for sale in its immediate condition, and the sale is probable within one year of the reporting date.
Assets held for sale are reported at the lower of cost or fair value less costs to sell. Assets held for sale were not significant at December 31, 2012 or 2011.
Accrued Expenses and Other
Included in Accrued expenses and
other at December 31, 2012 and 2011 were liabilities of $1.1 billion and $788 million for unredeemed gift certificates. We reduce the liability for a gift certificate when redeemed by a customer. If a gift certificate is not redeemed, we
recognize revenue when it expires or, for a certificate without an expiration date, when the likelihood of its redemption becomes remote, generally two years from the date of issuance.
Unearned revenue is recorded when payments are received in advance of performing our service obligations and is recognized over the service period. Unearned revenue primarily relates to Amazon Prime
memberships and AWS services. Current unearned revenue is included in Accrued expenses and other and non-current unearned revenue is included in Other long-term liabilities on our consolidated balance sheets. Current unearned
revenue was $792 million and $462 million at December 31, 2012 and 2011. Non-current unearned revenue was $108 million and $87 million at December 31, 2012 and 2011.
Income tax expense includes U.S. and international income
taxes. Except as required under U.S. tax law, we do not provide for U.S. taxes on our undistributed earnings of foreign subsidiaries that have not been previously taxed since we intend to invest such undistributed earnings indefinitely outside of
the U.S. If our intent changes or if these funds are needed for our U.S. operations, we would be required to accrue or pay U.S. taxes on some or all of these undistributed earnings. Undistributed earnings of foreign subsidiaries that are
indefinitely invested outside of the U.S were $2.1 billion at December 31, 2012. Determination of the unrecognized deferred tax liability that would be incurred if such amounts were repatriated is not practicable.
Deferred income tax balances reflect the effects of temporary differences between the carrying amounts of assets and liabilities and
their tax bases and are stated at enacted tax rates expected to be in effect when taxes are actually paid or recovered.
Deferred tax assets are evaluated for future realization and reduced by a valuation allowance to the extent we believe a portion will not
be realized. We consider many factors when assessing the likelihood of future realization of our deferred tax assets, including our recent cumulative earnings experience and expectations of future taxable income and capital gains by taxing
jurisdiction, the carry-forward periods available to us for tax reporting purposes, and other relevant factors. We allocate our valuation allowance to current and long-term deferred tax assets on a pro-rata basis.
We utilize a two-step approach to recognizing and measuring uncertain income tax positions (tax contingencies). The first step is to
evaluate the tax position for recognition by determining if the weight of available evidence indicates it is more likely than not that the position will be sustained on audit, including resolution of related appeals or litigation processes. The
second step is to measure the tax benefit as the largest amount which is more than 50% likely of being realized upon ultimate settlement. We consider many factors when evaluating and estimating our tax positions and tax benefits, which may
require periodic adjustments and which may not accurately forecast actual outcomes. We include interest and penalties related to our tax contingencies in income tax expense.