Goodwill and Indefinite-lived Assets Pensions and Retiree Medical and Other Postretirement Benefits 74 Our pension and retiree medical and other postretirement benefits costs and liabilities are calculated using various actuarial assumptions and methodologies. We use certain assumptions including, but not limited to, the selection of the: (1) discount rate, (2) expected return on plan assets, (3) expected health care cost trend rate and (4) estimated age of pilot retirement (as discussed below). These assumptions as of December 31 were: We recognize the funded status (i.e., the difference between the fair value of plan assets and the projected benefit obligations) of our pension and retiree medical and other postretirement benefits plans in the consolidated balance sheets with a corresponding adjustment to accumulated other comprehensive income (loss). Based upon our annual assessment, there were no impairments of our goodwill and no additional impairments of our indefinite-lived assets in 2018 other than the Brazil route authority described above. Goodwill and indefinite-lived intangible assets are assessed for impairment by initially performing a qualitative assessment. Under the qualitative approach, we analyze the following factors, among others, to determine if events and circumstances have affected the fair value of goodwill and indefinite-lived intangible assets: (1) negative trends in our market capitalization, (2) an increase in fuel prices, (3) declining per mile passenger yields, (4) lower passenger demand as a result of a weakened U.S. and global economy and (5) changes to the regulatory environment. In the second quarter of 2018, American recorded a $26 million impairment charge on a Brazil route authority as a result of the U.S.-Brazil open skies agreement. Indefinite-lived intangible assets other than goodwill include certain domestic airport slots at our hubs and international slots and route authorities. Indefinite-lived intangible assets are not amortized but instead are assessed for impairment annually on October 1$^{st}$ or more frequently if events or circumstances indicate that the asset may be impaired. Goodwill represents the excess of the purchase price over the fair value of the net assets acquired and liabilities assumed. Goodwill is not amortized but assessed for impairment annually on October 1 st or more frequently if events or circumstances indicate that goodwill may be impaired. We have one consolidated reporting unit. $^{(1)}$  When establishing our discount rate to measure our obligations, we match high quality corporate bonds available in the marketplace whose cash flows approximate our projected benefit disbursements. Lowering the discount rate by 50 basis points as of December 31, 2018 would increase our pension and retiree medical and other postretirement benefits obligations by approximately $1.1 billion and $37 million, respectively, and increase both estimated 2019 pension expense and estimated 2019 retiree medical and other postretirement benefits expense by $2 million and less than $1 million, respectively. $^{(2)}$  The expected rate of return on plan assets is based upon an evaluation of our historical trends and experience, taking into account current and expected market conditions and our target asset allocation of 30% U.S. stocks, 22% developed international stocks, 20% fixed income securities, 20% alternative (private) investments and 8% emerging market stocks. The expected rate of return on plan assets component of our net periodic benefit cost is calculated based on the fair value of plan assets and our target asset allocation. Lowering the expected long- term rate of return on plan assets by 50 basis points as of December 31, 2018 would increase estimated 2019 pension expense and retiree medical and other postretirement benefits expense by approximately $51 million and $1 million, respectively. 2018 2017 Pension weighted average discount rate  (1) 4.40 % 3.80 % Retiree medical and other postretirement benefits weighted average discount rate  (1) 4.30% 3.60% Expected rate of return on plan assets  (2) 8.00 % 8.00 % Weighted average health care cost trend rate assumed for next year $^{(3)}$: Initial 3.91 % 4.19 % Ultimate (2026) 3.45% 3.76% Assumed Pilot Retirement Age 63 62