AMR Corporation $($parent company of American Airlines$)$ reported the following $($in millions$).$

Service cost $$366$

Interest on P$.$B$.$O$.737$

Return on plan assets $593$

Amortization of prior service cost $13$

Amortization of net loss $154$

Computer AMR's pension expense.

Pension expense $\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_$