Classification and presentation are governed by ASC 205-20. After ASU 2014-08, only disposals that amount to a strategic shift qualify, such as exiting a major line of business or a major geographic area. Selling a single store, plant, or small product line usually does not. Regulation S-X Rule 5-03.14 gives discontinued operations its own caption, placed after income from continuing operations and before net income.
In XBRL the total is IncomeLossFromDiscontinuedOperationsNetOfTax, including any portion owned by noncontrolling holders, with IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity giving the parent's share. The disposal gain or loss is often broken out as DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax. The amount is shown net of its own income tax, so it does not flow through the income tax expense line. Earnings per share for discontinued operations must also be shown separately.
When a unit is reclassified, prior periods are recast so that every year presented treats it as discontinued. This makes historical revenue and operating income comparable, but it means figures from an older filing may not match the same year in a newer one. Analysts generally build forecasts and valuation multiples on continuing operations and treat discontinued results, especially large disposal gains, as non-recurring.