$^{(3)}$  The assumed health care cost trend rate is based upon an evaluation of our historical trends and experience, taking into account current and expected market conditions. Increasing the assumed health care cost trend rate by 100 basis points would increase estimated 2019 retiree medical and other postretirement benefits expense by $6 million. During 2018, we reviewed and revised certain economic and demographic assumptions including the pension and retiree medical and other postretirement benefits discount rates, retirement rates and health care cost and trend rates. The net effect of changing these assumptions for the pension plans resulted in a decrease of $1.8 billion in the projected benefit obligation at December 31, 2018. The net effect of changing these assumptions for retiree medical and other postretirement benefits plans resulted in a decrease of $126 million in the projected benefit obligation at December 31, 2018. We also revised our mortality assumptions to incorporate the new mortality improvement scale issued by the Society of Actuaries. This resulted in a decrease in the projected benefit obligations of our pension and retiree medical and other postretirement benefits plans of $58 million and $1 million, respectively. See Note 10 to AAG’s Consolidated Financial Statements in Part II, Item 8A and Note 8 to American’s Consolidated Financial Statements in Part II, Item 8B for additional information regarding our employee benefit plans. Effective January 1, 2018, we adopted the accounting pronouncements described below. The New Revenue Standard applies to all companies that enter into contracts with customers to transfer goods or services. We adopted the New Revenue Standard using the full retrospective method, which resulted in the recast of prior reporting periods. The adoption of the New Revenue Standard impacted our accounting for outstanding mileage credits earned through travel by AAdvantage loyalty program members. There was no change in accounting for sales of mileage credits to co-branded credit card or other partners. Prior to the adoption of the New Revenue Standard, we used the incremental cost method to account for the portion of our loyalty program liability related to mileage credits earned through travel, which were valued based on the estimated incremental cost of carrying one additional passenger. The New Revenue Standard required us to change our policy to the deferred revenue method and apply a relative selling price approach whereby a portion of each passenger ticket sale attributable to mileage credits earned is deferred and recognized in passenger revenue upon future mileage redemption. The value of the earned mileage credits is materially greater under the deferred revenue method than the value attributed to these mileage credits under the incremental cost method. The New Revenue Standard also required certain reclassifications, principally the reclassification of certain ancillary revenues previously classified and reported as other revenue to passenger revenue and as applicable to cargo revenue. Additionally, the New Revenue Standard required a gross presentation on the face of our consolidated statements of operations for certain revenues and expenses that had previously been presented on a net basis. See  “Impacts to 2017 Results”  and  “Impacts to 2016 Results”  below for the impact to our consolidated statements of operations data for 2017 and 2016, respectively, and our consolidated balance sheet as of December 31, 2017 related to the adoption of the New Revenue Standard. The New Retirement Standard required all components of our net periodic benefit cost (income), with the exception of service cost, previously reported within operating expenses as salaries, wages and benefits, to be reclassified and reported within nonoperating income (expense). The New Retirement Standard was applied retrospectively, which resulted in the recast of each prior reporting period presented. The adoption of the New Retirement Standard had no impact on pre-tax income or net income reported. See  “Impacts to 2017 Results”  and  “Impacts to 2016 Results”  below for the impact to our consolidated statements of operations data for 2017 and 2016, respectively, related to the adoption of the New Retirement Standard. 75 ASU 2017-07: Compensation - Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost (the New Retirement Standard) ASU 2014-09: Revenue from Contracts with Customers (Topic 606) (the New Revenue Standard) Recent Accounting Pronouncements Standards Adopted in 2018