At December 31, 2018, the Company had approximately 4,500 employees, of which approximately 200 were temporary employees. Some of the Company’s employees in various foreign locations are subject to collective bargaining agreements. Less than one percent of the Company’s employees in the U.S. are subject to collective bargaining agreements.

The Company has benefit plans covering substantially all of its employees. Defined contribution benefit plans cover most of the U.S. and Canadian employees, and benefits are based on years of service, a percentage of current earnings and matching of employee contributions. For the years ended December 31, 2018, 2017 and 2016, employer contributions for defined contribution plans were $13 million, $12 million, and $13 million, respectively, and all funding is current.

The Company has a non-qualified deferred compensation plan (the “NQDC Plan”) for certain members of senior management. NQDC Plan assets are invested in mutual funds held in a “rabbi trust,” which is restricted for payment to participants of the NQDC Plan. Such equity securities held in a rabbi trust are measured using quoted market prices at the reporting date (Level 1 within the fair value hierarchy) and are included in other assets, with the corresponding liability included in other long-term liabilities in the consolidated balance sheets.

The Company sponsors two defined benefit plans in the United Kingdom under which accrual of pension benefits have ceased. Plan member benefits that have previously been accrued are indexed in line with inflation during the period up to retirement in order to protect their purchasing power. The second defined benefit plan was acquired from the John MacLean & Sons Electrical acquisition in March 2015. Net periodic benefit cost for the Company’s defined benefit plans aggregated less than $1 million each year for the years ended December 31, 2018, 2017 and 2016 are included in warehousing, selling and administrative in the consolidated statement of operations.

The change in benefit obligation, plan assets and the funded status of the defined benefit pension plans in the United Kingdom using a measurement date of December 31, 2018 and 2017, are as follows (in millions):

	Pension Benefits
At year end	2018			2017
Benefit obligation at beginning of year	$	13		$	13
Interest cost		—			—
Actuarial loss (gain)		1			1
Benefits paid		—			—
Plan settlements		(3	)		—
Foreign currency exchange rate changes		—			(1	)
Benefit obligation at end of year		11			13

Fair value of plan assets at beginning of year	$	18		$	15
Actual return		—			2
Benefits paid		—			—
Company contributions		—			1
Plan settlements		(3	)		—
Foreign currency exchange rate changes		—			—
Fair value of plan assets at end of year		15			18

Funded status		4			5
Accumulated benefit obligation at end of year		11			13

The net asset is presented within other assets in the consolidated balance sheets.

Assumed long-term rates of return on plan assets and discount rates vary for the different plans according to the local economic conditions. The assumption rates used for benefit obligations are as follows:

In determining the overall expected long-term rate of return for plan assets, the Company takes into consideration the historical experience as well as future expectations of the asset mix involved. As different investments yield different returns, each asset category is reviewed individually and then weighted for significance in relation to the total portfolio.

Both plans have plan assets in excess of projected benefit obligations. The Company expects to pay future benefit amounts on its defined benefit plans of less than $1 million for each of the next five years and in the aggregate $2 million for the five years thereafter. The Company expects to contribute less than $1 million to its defined benefit pension plans in 2019.

The Company and its investment advisers collaboratively reviewed market opportunities using historic and statistical data, as well as the actuarial valuation reports for the plans, to ensure that the levels of acceptable return and risk are well-defined and monitored. Currently, the Company’s management believes that there are no significant concentrations of risk associated with plan assets.

The following table sets forth by level, within the fair value hierarchy, the plan’s assets carried at fair value (in millions):

	Fair Value Measurements
	Total		Level 1		Level 2		Level 3
December 31, 2018:
Equity securities	$	5	$	5	$	—	$	—
Fixed income securities		5		5		—		—
Other		5		—		5		—
Total fair value measurements	$	15	$	10	$	5	$	—

December 31, 2017:
Equity securities	$	10	$	10	$	—	$	—
Fixed income securities		3		3		—		—
Other		5		—		5		—
Total fair value measurements	$	18	$	13	$	5	$	—