The Company has a defined contribution savings plan covering the eligible U.S. regular full-time and part-time employees, whereby eligible employees may elect to contribute up to 100% of their annual eligible compensation, subject to an annual plan limit in line with the annual elective contribution limit as determined by the Internal Revenue Service. The Company matches its employee's contribution up to a certain percentage of such employee's compensation, per the terms of the plan. The Company may, at its discretion and per the terms of the plan, make an additional non-matching contribution in an amount as the Board of Directors may determine. For the years ended December 31, 2019, 2018 and 2017, the Company recorded approximately $20, $21 and $23, respectively, to expense for these contributions.

Further, within the plan, the Company also makes an annual retirement contribution to substantially all employees of certain subsidiaries. The Company's contributions to the plan are determined as a percentage of employees' pay. For the years ended December 31, 2019, 2018 and 2017, the Company charged approximately $32, $31 and $29, respectively, to expense for these contributions.

The Company has defined contribution plans in several countries covering eligible employees of the Company. The Company's contributions to the plans are based on applicable laws in each country. Contributions to the Company's non-U.S. defined contribution plans are made by both the employee and the Company. For the years ended December 31, 2019, 2018 and 2017, the Company charged approximately $4, $5 and $5, respectively, to expense for its contributions to these plans.

The Company has noncontributory defined benefit pension plans that cover certain eligible salaried and wage employees of certain subsidiaries. However, eligibility for the Company's plans has been frozen. Benefits for salaried employees under these plans are based primarily on years of service and employees' pay near retirement. Benefits for wage employees are based upon years of service and a fixed amount as periodically adjusted. The Company recognizes the years of service prior to the Company's acquisition of the subsidiary's facilities for purposes of determining vesting, eligibility and benefit levels for certain employees of the subsidiary and for determining vesting and eligibility for certain other employees of the subsidiary. The measurement date for these plans is December 31.

The Company has defined benefit pension plans covering current and former employees associated with the Company's operations. These pension plans are closed to new participants. Benefits for employees for these plans are based primarily on employees' pay near retirement. These pension plans are unfunded and have no plan assets. The measurement date for the non-U.S. plans is December 31.



	2019						2018
	U.S. Plans			Non-U.S. Plans			U.S. Plans			Non-U.S. Plans
Change in benefit obligation
Benefit obligation, beginning of year	$	648		$	136		$	807		$	142
Service cost	3			2			3			2
Interest cost	23			3			24			3
Actuarial loss (gain)	80			14			(43		)	—
Benefits paid	(51		)	(4		)	(40		)	(4		)
Plan amendments	—			(4		)	—			—
Settlements	—			(1		)	(103		)	—
Foreign exchange effects	—			(2		)	—			(7		)
Benefit obligation, end of year	$	703		$	144		$	648		$	136

Change in plan assets
Fair value of plan assets, beginning of year	$	486		$	17		$	650		$	18
Actual return	92			1			(22		)	—
Employer contribution	2			—			3			1
Benefits paid	(51		)	—			(40		)	(1		)
Administrative expenses paid	(3		)	—			(2		)	—
Settlements	—			—			(103		)	—
Foreign exchange effects	—			1			—			(1		)
Fair value of plan assets, end of year	$	526		$	19		$	486		$	17
Funded status, end of year	$	(177	)	$	(125	)	$	(162	)	$	(119	)



	2019						2018
	U.S. Plans			Non-U.S. Plans			U.S. Plans			Non-U.S. Plans
Amounts recognized in the consolidated balance sheet at December 31
Current liabilities	$	(2	)	$	(2	)	$	(2	)	$	(3	)
Noncurrent liabilities	(175		)	(123		)	(160		)	(116		)
Net amount recognized	$	(177	)	$	(125	)	$	(162	)	$	(119	)



	2019						2018
	U.S. Plans			Non-U.S. Plans			U.S. Plans			Non-U.S. Plans
Amounts recognized in accumulated other comprehensive income (loss)
Net loss (gain)	$	(16	)	$	22		$	(36	)	$	9
Prior service cost	—			(4		)	—			—
Total before tax ⁽¹⁾	$	(16	)	$	18		$	(36	)	$	9

In the U.S., the Pension Protection Act of 2006 (the "Pension Protection Act") established a relationship between a qualified pension plan's funded status and the actual benefits that can be provided. Restrictions on plan benefits and additional funding and notice requirements are imposed when a plan's funded status is less than certain threshold levels. For the 2019 plan year, the funded status for the Company's U.S. pension plans are above 80% and, as such, are exempt from the Pension Protection Act's benefit restrictions.



	2019						2018
	U.S. Plans			Non-U.S. Plans			U.S. Plans			Non-U.S. Plans
Information for pension plans with an accumulated benefit obligation in excess of plan assets
Projected benefit obligation	$	(703	)	$	(143	)	$	(648	)	$	(128	)
Accumulated benefit obligation	(703		)	(138		)	(648		)	(125		)
Fair value of plan assets	526			18			486			10



	Year Ended December 31,
	2019						2018						2017
	U.S. Plans			Non-U.S. Plans			U.S. Plans			Non-U.S. Plans			U.S. Plans			Non-U.S. Plans
Components of net periodic benefit cost
Service cost	$	3		$	2		$	3		$	2		$	3		$	2
Administrative expenses	4			—			3			—			2			—
Interest cost	23			3			24			3			25			2
Expected return on plan assets	(33		)	(1		)	(42		)	(1		)	(40		)	(1		)
Net amortization	—			—			(1		)	1			1			1
Settlement gain	—			—			(14		)	—			—			—
Net periodic benefit cost (gain)	$	(3	)	$	4		$	(27	)	$	5		$	(9	)	$	4

Other changes in plan assets and benefit obligation recognized in other comprehensive income (OCI)
Net loss (gain) emerging	$	20		$	13		$	20		$	1		$	(18	)	$	—
Settlement gain	—			—			14			—			—			—
Effect of plan change	—			(4		)	—			—			—			—
Amortization of net gain (loss)	—			—			1			(1		)	(1		)	(1		)
Total recognized in OCI	$	20		$	9		$	35		$	—		$	(19	)	$	(1	)
Total net periodic benefit cost and OCI	$	17		$	13		$	8		$	5		$	(28	)	$	3

The estimated prior service cost and net loss for the defined benefit plans to be amortized from accumulated other comprehensive income (loss) into net periodic benefit cost during 2020 are expected to be zero and $1, respectively.

During 2018, the Company's U.S. pension plans settled portions of their projected benefit obligations through the purchase of annuities and lump sum payments to certain participants. In conjunction with the settlement, the Company also remeasured the pension obligations and plan assets of the affected plans, resulting in a $26 increase in accumulated other comprehensive income (loss) before tax and a corresponding decrease in net pension liabilities recorded in the consolidated balance sheets. During 2018, the Company recognized a $14 one-time settlement gain in other income, net, which was reclassified from accumulated other comprehensive income (loss).



	2019				2018				2017
	U.S. Plans		Non-U.S. Plans		U.S. Plans		Non-U.S. Plans		U.S. Plans		Non-U.S. Plans
Weighted average assumptions used to determine benefit obligations at December 31
Discount rate	3.0	%	1.3	%	4.1	%	2.0	%	3.4	%	1.8	%
Rate of compensation increase	—	%	2.6	%	—	%	2.6	%	—	%	2.6	%
Weighted average assumptions used to determine net periodic benefit costs for years ended December 31
Discount rate for benefit obligations	4.1	%	2.0	%	3.4	%	1.8	%	3.8	%	1.8	%
Discount rate for service cost	4.2	%	2.2	%	3.8	%	2.0	%	4.1	%	1.9	%
Discount rate for interest cost	3.7	%	2.2	%	3.3	%	2.0	%	3.2	%	2.0	%
Expected return on plan assets	7.0	%	4.0	%	7.0	%	3.8	%	6.8	%	3.8	%
Rate of compensation increase	—	%	2.6	%	—	%	2.6	%	—	%	2.6	%

The discount rates for the Company's U.S. and non-U.S. plans are determined using a benchmark pension discount curve and applying spot rates from the curve to each year of expected benefit payments to determine the appropriate discount rate for the Company. The assumed long-term return on plan assets is estimated by considering factors such as the plan's overall investment strategy, current economic conditions and historical averages.

The Company's U.S. pension plan investments are held in the Westlake Defined Benefit Plan. The Company's overall investment strategy for these pension plan assets is to achieve a balance between moderate income generation and capital appreciation. The investment strategy includes a mix of approximately 60% of investments for long-term growth, and 40% for near-term benefit payments with a diversification of asset types. These pension funds' investment policies target asset allocations from approximately 60% equity securities and 40% fixed income securities in order to pursue a balance between moderate income generation and capital appreciation.

Equity securities primarily include investments in large-cap and small-cap companies located in the U.S. and international developed and emerging markets stocks. Fixed income securities are comprised of investment and non-investment grade bonds, including U.S. Treasuries and U.S. and non-U.S. corporate bonds of companies from diversified industries. Each pension fund investment policy allows a discretionary range in various asset classes within the asset allocation model of up to 10%. The Company does not believe that there are significant concentrations of risk in the pension plan assets due to its strategy of asset diversification. At December 31, 2019, plan assets did not include direct ownership of the Company's common stock.

The investments in the collective trust and mutual funds are valued using a market approach based on the net asset value of units held. The fair values of the Company's U.S. plan assets at December 31, by asset category, are as follows:



	2019
	U.S. Plans						Non U.S. Plans
	Level 1		Level 2		Total		Level 1		Level 2		Total
Cash and common stock:
Cash and cash equivalents	$	—	$	—	$	—	$	6	$	—	$	6
Common stock	15		—		15		—		—		—
Collective investment trust and mutual funds—Equity securities:
Large-cap funds ⁽¹⁾	49		112		161		—		1		1
Small-cap funds ⁽²⁾	8		14		22		—		—		—
International funds ⁽³⁾	75		45		120		—		5		5
Collective investment trust and mutual funds—Fixed income:
Bond funds ⁽⁴⁾	100		98		198		—		7		7
Short-term investment funds	—		10		10		—		—		—
	$	247	$	279	$	526	$	6	$	13	$	19



	2018
	U.S. Plans						Non U.S. Plans
	Level 1		Level 2		Total		Level 1		Level 2		Total
Cash and common stock:
Cash and cash equivalents	$	—	$	—	$	—	$	5	$	—	$	5
Common stock	13		—		13		—		—		—
Collective investment trust and mutual funds—Equity securities:
Large-cap funds ⁽¹⁾	44		98		142		—		1		1
Small-cap funds ⁽²⁾	6		13		19		—		—		—
International funds ⁽³⁾	64		38		102		—		5		5
Collective investment trust and mutual funds—Fixed income:
Bond funds ⁽⁴⁾	96		102		198		—		6		6
Short-term investment funds	—		12		12		—		—		—
	$	223	$	263	$	486	$	5	$	12	$	17

The Company's funding policy for its U.S. plans is consistent with the minimum funding requirements of federal law and regulations, and based on preliminary estimates, the Company expects to make contributions of approximately $2 for the pension plans in 2020.

The Company participates in two multi-employer plans, Pensionskasse der Mitarbeiter der Hoechst-Gruppe VVaG and Pensionskasse der Wacker-Chemie GmbH VVaG, which provide benefits to certain of the Company's employees in Germany. These multi-employer plans are closed to new participants. The benefit obligations are covered up to a certain salary threshold by contributions made by the Company and employees to the plans.

In the U.S., the Company provides post-retirement healthcare and life insurance benefits for certain employees and their dependents who meet minimum age and service requirements. The Company has the right to modify or terminate some of these benefits.



	2019						2018
	U.S. Plans			Non-U.S. Plans			U.S. Plans			Non-U.S. Plans
Change in benefit obligation
Benefit obligation, beginning of year	$	67		$	3		$	73		$	3
Service cost	1			—			1			—
Interest cost	2			—			2			—
Actuarial loss (gain)	3			1			(1		)	—
Benefits paid	(8		)	—			(8		)	—
Benefit obligation, end of year	$	65		$	4		$	67		$	3

Change in plan assets
Fair value of plan assets, beginning of year	$	—		$	—		$	—		$	—
Employer contribution	8			—			8			—
Benefits paid	(8		)	—			(8		)	—
Fair value of plan assets, end of year	$	—		$	—		$	—		$	—
Funded status, end of year	$	(65	)	$	(4	)	$	(67	)	$	(3	)



	2019						2018
	U.S. Plans			Non-U.S. Plans			U.S. Plans			Non-U.S. Plans
Amounts recognized in the consolidated balance sheet at December 31
Current liabilities	$	(8	)	$	—		$	(8	)	$	—
Noncurrent liabilities	(57		)	(5		)	(59		)	(3		)
Net amount recognized	$	(65	)	$	(5	)	$	(67	)	$	(3	)



	2019					2018
	U.S. Plans			Non-U.S. Plans		U.S. Plans			Non-U.S. Plans
Amounts recognized in accumulated other comprehensive income (loss)
Net gain	$	(3	)	$	—	$	(6	)	$	—
Total before tax ⁽¹⁾	$	(3	)	$	—	$	(6	)	$	—



	Year Ended December 31,
	2019				2018						2017
	U.S. Plans		Non-U.S. Plans		U.S. Plans			Non-U.S. Plans			U.S. Plans			Non-U.S. Plans
Components of net periodic benefit cost
Service cost	$	1	$	—	$	1		$	—		$	1		$	—
Interest cost	2		—		2			—			2			—
Net amortization	—		—		—			—			—			—
Net periodic benefit cost	$	3	$	—	$	3		$	—		$	3		$	—

Other changes in plan assets and benefit obligation recognized in OCI
Net loss (gain) emerging	$	3	$	—	$	(1	)	$	(1	)	$	(1	)	$	—
Total recognized in OCI	$	3	$	—	$	(1	)	$	(1	)	$	(1	)	$	—
Total net periodic benefit cost and OCI	$	6	$	—	$	2		$	(1	)	$	2		$	—

The estimated prior service cost and net loss for the post-retirement healthcare benefit plans that will be amortized from accumulated other comprehensive income (loss) into net periodic benefit cost during 2020 are both expected to be zero.



	2019				2018				2017
	U.S. Plans		Non-U.S. Plans		U.S. Plans		Non-U.S. Plans		U.S. Plans		Non-U.S. Plans
Weighted average assumptions used to determine benefit obligations at December 31
Discount rate	2.5	%	3.2	%	3.7	%	3.9	%	3.0	%	4.0	%
Health care cost trend rate
- Initial rate	6.8	%	5.7	%	7.0	%	5.8	%	7.3	%	6.2	%
- Ultimate rate	4.5	%	4.0	%	4.5	%	4.0	%	4.5	%	4.5	%
- Years to ultimate	10		21		11		22		11		12
Weighted average assumptions used to determine net periodic benefit costs for years ended December 31
Discount rate for benefit obligations	3.7	%	3.9	%	3.0	%	3.6	%	3.3	%	3.3	%
Discount rate for service cost	4.0	%	3.9	%	3.4	%	3.6	%	3.8	%	3.3	%
Discount rate for interest cost	3.4	%	3.9	%	2.7	%	3.6	%	2.6	%	3.3	%
Health care cost trend rate
- Initial rate	7.0	%	5.8	%	7.0	%	6.1	%	6.8	%	6.8	%
- Ultimate rate	4.5	%	4.0	%	4.5	%	4.5	%	4.6	%	4.5	%
- Years to ultimate	10		21		10		11		11		12

The discount rate is determined using a benchmark pension discount curve and applying spot rates from the curve to each year of expected benefit payments to determine the appropriate discount rate for the Company. A one percentage-point increase or decrease in assumed healthcare trend rates would not have a significant effect on the amounts reported for the healthcare plans.