Delphi operates its core business along the following operating segments, which are grouped on the basis of similar product, market and operating factors:

The accounting policies of the segments are the same as those described in Note 2. Significant Accounting Policies, except that the disaggregated financial results for the segments have been prepared using a management approach, which is consistent with the basis and manner in which management internally disaggregates financial information for the purposes of assisting internal operating decisions. Generally, Delphi evaluates performance based on stand-alone segment net income before interest expense, other income (expense), net, income tax expense, equity income (loss), net of tax, income (loss) from discontinued operations, net of tax, restructuring, other project and integration costs related to acquisitions and other portfolio transactions and asset impairments (“Adjusted Operating Income”) and accounts for inter-segment sales and transfers as if the sales or transfers were to third parties, at current market prices. Delphi’s management utilizes Adjusted Operating Income as the key performance measure of segment income or loss and for planning and forecasting purposes, as management believes this measure is most reflective of the operational profitability or loss of Delphi's operating segments. Segment Adjusted Operating Income should not be considered a substitute for results prepared in accordance with U.S. GAAP and should not be considered an alternative to net income attributable to Delphi, which is the most directly comparable financial measure to Adjusted Operating Income that is in accordance with U.S. GAAP. Segment Adjusted Operating Income, as determined and measured by Delphi, should also not be compared to similarly titled measures reported by other companies.

At March 31, 2015, the Company determined that its previously reported Thermal Systems segment met the criteria to be classified as a discontinued operation, which required retrospective application to balance sheet, statement of operations and certain cash flow financial information for all periods presented. Refer to Note 21. Discontinued Operations for further information regarding the Company's discontinued operations. Discontinued operations also includes the Company's thermal original equipment service business, the results of which were previously reported within the Powertrain Systems segment. Certain operations, primarily related to contract manufacturing services, which were previously included within the Thermal Systems reporting segment but which are not included in the scope of the planned disposal, are reported in continuing operations and have been reclassified within the Electronics and Safety segment for all periods presented. Amounts for shared general and administrative operating expenses that were allocated to the Thermal Systems business in prior periods have been re-allocated to the Company's reportable operating segments.