Retirement and Employee Benefit Plans

We have defined contribution plans covering certain employees. Contribution expenses related to these plans totaled $24 million, $30 million and $66 million in 2017, 2016 and 2015, respectively. The decrease in employer contributions in 2017 and 2016 relates primarily to headcount reductions and the suspension of employer matching contributions to our U.S. 401(k) savings plan and other contribution plans sponsored by the Company.

We have defined benefit pension and other post-retirement benefit plans covering certain U.S. and international employees. Plan benefits are generally based on factors such as age, compensation levels and years of service. Net periodic benefit income/cost related to these plans totaled $38 million of income in 2017 due primarily to amortization of the unrecognized net gain associated with our supplemental executive retirement plan and $9 million of cost in 2016 and 2015, respectively. The projected benefit obligations on a consolidated basis were $198 million and $205 million as of December 31, 2017 and 2016, respectively. The decrease year over year is due primarily to settlements offset by increases related to currency fluctuations in Euro and British Pound denominated plans. The fair values of plan assets on a consolidated basis (determined primarily using Level 2 inputs) were $133 million and $118 million as of December 31, 2017 and 2016, respectively. The increase in plan assets year over year is also due primarily to the Euro and British Pound currency fluctuations. As of December 31, 2017, the net underfunded obligation was substantially all recorded within Other Non-current Liabilities. As of December 31, 2016, the net underfunded obligation was primarily recorded within Other Non-current Liabilities with approximately $22 million recorded in Accrued Salaries and Benefits. Additionally, consolidated pre-tax amounts in accumulated other comprehensive income that have not yet been recognized as components of net periodic benefit cost were loss of $35 million and income of $3 million as of December 31, 2017 and 2016, respectively. The change in other comprehensive income (loss) year over year is due primarily to the amortization of the unrecognized net gain mentioned above.

The weighted average assumption rates used for benefit obligations were as follows:



	Year Ended December 31,
	2017	2016
Discount rate:
United States Plans	3.00% - 3.50%	1.00% - 4.00%
International Plans	1.60% - 6.75%	1.90% - 7.50%
Rate of Compensation Increase:
United States Plans	—	—
International Plans	2.00% - 3.50%	2.00% - 3.50%

During 2017 and 2016, we made contributions and paid direct benefits of $23 million and $6 million, respectively, in connection with our defined benefit pension and other post-retirement benefit plans. In 2018, we expect to fund approximately $5 million related to those plans.