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Employee Benefit Plans
12 Months Ended
Dec. 31, 2015
Compensation and Retirement Disclosure [Abstract]  
Employee Benefit Plans
Employee Benefit Plans
Pension and other postretirement benefit plans
The Company has noncontributory defined benefit pension plans and other postretirement benefit plans for certain eligible employees. The Company uses a measurement date of December 31 for all of its pension and postretirement benefit plans.
Prior to 2013, defined pension plan benefits and accruals for all nonunion and certain union plans were frozen. On June 30, 2015, an additional union plan was frozen. At December 31, 2015, all of the Company's defined pension plans have been frozen. These employees will be eligible to receive additional defined contribution plan benefits.
Effective January 1, 2010, eligibility to receive retiree medical benefits was modified at certain of the Company's businesses. Employees who had attained age 55 with 10 years of continuous service by December 31, 2010, will be provided the current retiree medical insurance benefits or can elect the new benefit, if desired, regardless of when they retire. All other current employees must meet the new eligibility criteria of age 60 and 10 years of continuous service at the time they retire. These employees will be eligible for a specified company funded Retiree Reimbursement Account. Employees hired after December 31, 2009, will not be eligible for retiree medical benefits at certain of the Company's businesses.
In 2012, the Company modified health care coverage for certain retirees. Effective January 1, 2013, post-65 coverage was replaced by a fixed-dollar subsidy for retirees and spouses to be used to purchase individual insurance through an exchange.
Changes in benefit obligation and plan assets for the years ended December 31, 2015 and 2014, and amounts recognized in the Consolidated Balance Sheets at December 31, 2015 and 2014, were as follows:
 
Pension Benefits
Other
Postretirement Benefits
 
2015

2014

2015

2014

 
(In thousands)
Change in benefit obligation:
 
 
 
 
Benefit obligation at beginning of year
$
475,337

$
402,772

$
99,012

$
81,726

Service cost
86

129

1,816

1,518

Interest cost
17,141

17,682

3,607

3,521

Plan participants' contributions


1,408

1,399

Actuarial (gain) loss
(24,875
)
80,520

(5,873
)
18,024

Benefits paid
(24,729
)
(25,766
)
(7,236
)
(7,176
)
Benefit obligation at end of year
442,960

475,337

92,734

99,012

Change in net plan assets:
 

 

 

 

Fair value of plan assets at beginning of year
354,363

334,844

87,586

84,543

Actual gain (loss) on plan assets
(10,879
)
24,500

258

7,527

Employer contribution
13,912

20,785

577

1,293

Plan participants' contributions


1,408

1,399

Benefits paid
(24,729
)
(25,766
)
(7,236
)
(7,176
)
Fair value of net plan assets at end of year
332,667

354,363

82,593

87,586

Funded status - under
$
(110,293
)
$
(120,974
)
$
(10,141
)
$
(11,426
)
Amounts recognized in the Consolidated
Balance Sheets at December 31:
 

 

 

 

Other assets (noncurrent)
$

$

$
5,095

$
4,345

Other accrued liabilities (current)


(421
)
(322
)
Other liabilities (noncurrent)
(110,293
)
(120,974
)
(14,815
)
(15,449
)
Net amount recognized
$
(110,293
)
$
(120,974
)
$
(10,141
)
$
(11,426
)
Amounts recognized in accumulated other
comprehensive (income) loss consist of:
 

 

 

 

Actuarial loss
$
208,671

$
207,430

$
22,484

$
25,779

Prior service cost (credit)

294

(14,374
)
(15,744
)
Total
$
208,671

$
207,724

$
8,110

$
10,035


Employer contributions and benefits paid in the preceding table include only those amounts contributed directly to, or paid directly from, plan assets. Accumulated other comprehensive (income) loss in the above table includes amounts related to regulated operations, which are recorded as regulatory assets (liabilities) and are expected to be reflected in rates charged to customers over time. For more information on regulatory assets (liabilities), see Note 4.
Unrecognized pension actuarial losses in excess of 10 percent of the greater of the projected benefit obligation or the market-related value of assets are amortized over the average life expectancy of plan participants for frozen plans. The market-related value of assets is determined using a five-year average of assets.
The pension plans all have accumulated benefit obligations in excess of plan assets. The projected benefit obligation, accumulated benefit obligation and fair value of plan assets for these plans at December 31 were as follows:
 
2015

2014

 
(In thousands)
Projected benefit obligation
$
442,960

$
475,337

Accumulated benefit obligation
$
442,960

$
475,337

Fair value of plan assets
$
332,667

$
354,363


Components of net periodic benefit cost (credit) for the Company's pension and other postretirement benefit plans for the years ended December 31 were as follows:
 
Pension Benefits
Other
Postretirement Benefits
 
2015

2014

2013

2015

2014

2013

 
(In thousands)
Components of net periodic benefit cost (credit):
 
 
 
 
 
 
Service cost
$
86

$
129

$
155

$
1,816

$
1,518

$
1,675

Interest cost
17,141

17,682

16,249

3,607

3,521

3,215

Expected return on assets
(22,254
)
(21,218
)
(19,917
)
(4,795
)
(4,617
)
(4,343
)
Amortization of prior service cost (credit)
36

71

71

(1,371
)
(1,393
)
(1,457
)
Recognized net actuarial loss
7,016

4,869

7,173

1,960

649

1,814

Curtailment loss
258






Net periodic benefit cost (credit), including amount capitalized
2,283

1,533

3,731

1,217

(322
)
904

Less amount capitalized
316

388

727

120

(21
)
164

Net periodic benefit cost (credit)
1,967

1,145

3,004

1,097

(301
)
740

Other changes in plan assets and benefit
obligations recognized in accumulated other
comprehensive (income) loss:
 

 

 

 

 

 

Net (gain) loss
8,257

77,238

(60,173
)
(1,336
)
15,114

(30,461
)
Amortization of actuarial loss
(7,016
)
(4,869
)
(7,173
)
(1,960
)
(649
)
(1,814
)
Amortization of prior service (cost) credit
(294
)
(71
)
(71
)
1,371

1,393

1,457

Total recognized in accumulated other
comprehensive (income) loss
947

72,298

(67,417
)
(1,925
)
15,858

(30,818
)
Total recognized in net periodic benefit cost (credit) and
accumulated other comprehensive (income) loss
$
2,914

$
73,443

$
(64,413
)
$
(828
)
$
15,557

$
(30,078
)

The estimated net loss for the defined benefit pension plans that will be amortized from accumulated other comprehensive loss into net periodic benefit cost in 2016 is $6.2 million. The estimated net loss and prior service credit for the other postretirement benefit plans that will be amortized from accumulated other comprehensive loss into net periodic benefit cost in 2016 are $1.5 million and $1.4 million, respectively. Prior service cost is amortized on a straight line basis over the average remaining service period of active participants.
Weighted average assumptions used to determine benefit obligations at December 31 were as follows:
 
Pension Benefits
Other
Postretirement Benefits
 
2015

2014

2015

2014

Discount rate
4.00
%
3.70
%
4.06
%
3.74
%
Expected return on plan assets
6.75
%
7.00
%
5.75
%
6.00
%
Rate of compensation increase
N/A

N/A

3.00
%
3.00
%
Weighted average assumptions used to determine net periodic benefit cost for the years ended December 31 were as follows:
 
Pension Benefits
Other
Postretirement Benefits
 
2015

2014

2015

2014

Discount rate
3.70
%
4.53
%
3.74
%
4.48
%
Expected return on plan assets
7.00
%
7.00
%
6.00
%
6.00
%
Rate of compensation increase
N/A

N/A

3.00
%
3.00
%
The expected rate of return on pension plan assets is based on a targeted asset allocation range determined by the funded ratio of the plan. As of December 31, 2015, the expected rate of return on pension plan assets is based on the targeted asset allocation range of 40 percent to 50 percent equity securities and 50 percent to 60 percent fixed-income securities and the expected rate of return from these asset categories. The expected rate of return on other postretirement plan assets is based on the targeted asset allocation range of 30 percent to 40 percent equity securities and 60 percent to 70 percent fixed-income securities and the expected rate of return from these asset categories. The expected return on plan assets for other postretirement benefits reflects insurance-related investment costs.
Health care rate assumptions for the Company's other postretirement benefit plans as of December 31 were as follows:
 
 
 
2015

 
 
2014

Health care trend rate assumed for next year
4.0
%
8.0
%
4.0
%
7.0
%
Health care cost trend rate - ultimate
5.0
%
6.0
%
5.0
%
6.0
%
Year in which ultimate trend rate achieved
 

2021



 
2017


The Company's other postretirement benefit plans include health care and life insurance benefits for certain retirees. The plans underlying these benefits may require contributions by the retiree depending on such retiree's age and years of service at retirement or the date of retirement. The accounting for the health care plans anticipates future cost-sharing changes that are consistent with the Company's expressed intent to generally increase retiree contributions each year by the excess of the expected health care cost trend rate over six percent.
Assumed health care cost trend rates may have a significant effect on the amounts reported for the health care plans. A one percentage point change in the assumed health care cost trend rates would have had the following effects at December 31, 2015:
 
1 Percentage
 Point Increase

1 Percentage
Point Decrease

 
(In thousands)
Effect on total of service and interest cost components
$
203

$
(169
)
Effect on postretirement benefit obligation
$
4,006

$
(3,407
)

The Company's pension assets are managed by 15 outside investment managers. The Company's other postretirement assets are managed by one outside investment manager. The Company's investment policy with respect to pension and other postretirement assets is to make investments solely in the interest of the participants and beneficiaries of the plans and for the exclusive purpose of providing benefits accrued and defraying the reasonable expenses of administration. The Company strives to maintain investment diversification to assist in minimizing the risk of large losses. The Company's policy guidelines allow for investment of funds in cash equivalents, fixed-income securities and equity securities. The guidelines prohibit investment in commodities and futures contracts, equity private placement, employer securities, leveraged or derivative securities, options, direct real estate investments, precious metals, venture capital and limited partnerships. The guidelines also prohibit short selling and margin transactions. The Company's practice is to periodically review and rebalance asset categories based on its targeted asset allocation percentage policy.
Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability (an exit price) in an orderly transaction between market participants at the measurement date. The ASC establishes a hierarchy for grouping assets and liabilities, based on the significance of inputs.
The estimated fair values of the Company's pension plans' assets are determined using the market approach.
The carrying value of the pension plans' Level 2 cash equivalents approximates fair value and is determined using observable inputs in active markets or the net asset value of shares held at year end, which is determined using other observable inputs including pricing from outside sources. Units of this fund can be redeemed on a daily basis at their net asset value and have no redemption restrictions. The assets are invested in high quality, short-term instruments of domestic and foreign issuers. There are no unfunded commitments related to this fund.
The estimated fair value of the pension plans' Level 1 equity securities is based on the closing price reported on the active market on which the individual securities are traded.
The estimated fair value of the pension plans' Level 1 and Level 2 collective and mutual funds are based on the net asset value of shares held at year end, based on either published market quotations on active markets or other known sources including pricing from outside sources. Units of these funds can be redeemed on a daily basis at their net asset value and have no redemption restrictions. There are no unfunded commitments related to these funds.
The estimated fair value of the pension plans' Level 2 corporate and municipal bonds is determined using other observable inputs, including benchmark yields, reported trades, broker/dealer quotes, bids, offers, future cash flows and other reference data.
The estimated fair value of the pension plans' Level 1 U.S. Government securities are valued based on quoted prices on an active market.
The estimated fair value of the pension plans' Level 2 U.S. Government securities are valued mainly using other observable inputs, including benchmark yields, reported trades, broker/dealer quotes, bids, offers, to be announced prices, future cash flows and other reference data. Some of these securities are valued using pricing from outside sources.
Though the Company believes the methods used to estimate fair value are consistent with those used by other market participants, the use of other methods or assumptions could result in a different estimate of fair value. For the years ended December 31, 2015 and 2014, there were no transfers between Levels 1 and 2.
The fair value of the Company's pension plans' assets (excluding cash) by class were as follows:
 
Fair Value Measurements
 at December 31, 2015, Using
 
 
Quoted Prices
in Active
Markets for
Identical
Assets
 (Level 1)

Significant
Other
Observable
Inputs
 (Level 2)

Significant
Unobservable
 Inputs
 (Level 3)

Balance at December 31, 2015

 
(In thousands)
Assets:
 
 
 
 
Cash equivalents
$

$
8,379

$

$
8,379

Equity securities:
 
 
 
 

U.S. companies
15,135



15,135

International companies
2,332



2,332

Collective and mutual funds*
154,400

63,568


217,968

Corporate bonds

62,145


62,145

Municipal bonds

11,680


11,680

U.S. Government securities
5,288

6,823


12,111

Total assets measured at fair value
$
177,155

$
152,595

$

$
329,750

*
Collective and mutual funds invest approximately 19 percent in common stock of large-cap U.S. companies, 6 percent in common stock of mid-cap U.S. companies, 16 percent in corporate bonds, 29 percent in common stock of international companies, 16 percent in cash equivalents and 14 percent in other investments.
 
 
Fair Value Measurements
 at December 31, 2014, Using
 
 
Quoted Prices
in Active
Markets for
Identical
Assets
 (Level 1)

Significant
Other
Observable
Inputs
 (Level 2)

Significant
Unobservable
 Inputs
 (Level 3)

Balance at December 31, 2014

 
(In thousands)
Assets:
 
 
 
 
Cash equivalents
$

$
5,631

$

$
5,631

Equity securities:
 
 
 
 

U.S. companies
39,077



39,077

International companies
5,189



5,189

Collective and mutual funds*
132,403

77,449


209,852

Corporate bonds

59,471


59,471

Municipal bonds

10,462


10,462

U.S. Government securities
15,001

6,849


21,850

Total assets measured at fair value
$
191,670

$
159,862

$

$
351,532

*
Collective and mutual funds invest approximately 13 percent in common stock of large-cap U.S. companies, 13 percent in U.S. Government securities, 23 percent in corporate bonds, 33 percent in common stock of international companies and 18 percent in other investments.
 

The estimated fair values of the Company's other postretirement benefit plans' assets are determined using the market approach.
The estimated fair value of the other postretirement benefit plans' Level 2 cash equivalents is valued at the net asset value of shares held at year end, based on published market quotations on active markets, or using other known sources including pricing from outside sources. Units of this fund can be redeemed on a daily basis at their net asset value and have no redemption restrictions. The assets are invested in high-quality, short-term money market instruments that consist of municipal obligations. There are no unfunded commitments related to this fund.
The estimated fair value of the other postretirement benefit plans' Level 1 equity securities is based on the closing price reported on the active market on which the individual securities are traded.
The estimated fair value of the other postretirement benefit plans' Level 2 insurance contract is based on contractual cash surrender values that are determined primarily by investments in managed separate accounts of the insurer. These amounts approximate fair value. The managed separate accounts are valued based on other observable inputs or corroborated market data.
Though the Company believes the methods used to estimate fair value are consistent with those used by other market participants, the use of other methods or assumptions could result in a different estimate of fair value. For the years ended December 31, 2015 and 2014, there were no transfers between Levels 1 and 2.
The fair value of the Company's other postretirement benefit plans' assets (excluding cash) by asset class were as follows:
 
Fair Value Measurements
 at December 31, 2015, Using
 
 
Quoted Prices
in Active
Markets for
Identical
Assets
 (Level 1)

Significant
Other
Observable
Inputs
 (Level 2)

Significant
Unobservable
Inputs
 (Level 3)

Balance at December 31, 2015

 
(In thousands)
Assets:
 
 
 
 
Cash equivalents
$

$
3,261

$

$
3,261

Equity securities:






 

U.S. companies
2,274



2,274

International companies
9



9

Insurance contract*

77,044


77,044

Total assets measured at fair value
$
2,283

$
80,305

$

$
82,588

*
The insurance contract invests approximately 19 percent in common stock of large-cap U.S. companies, 22 percent in U.S. Government securities, 10 percent in mortgage-backed securities, 36 percent in corporate bonds and 13 percent in other investments.
 
 
Fair Value Measurements
 at December 31, 2014, Using
 
 
Quoted Prices
in Active
Markets for
Identical
Assets
 (Level 1)

Significant
Other
Observable
Inputs
 (Level 2)

Significant
Unobservable
Inputs
 (Level 3)

Balance at December 31, 2014

 
(In thousands)
Assets:
 
 
 
 
Cash equivalents
$

$
2,097

$

$
2,097

Equity securities:
 
 
 
 

U.S. companies
2,614



2,614

International companies
25



25

Insurance contract*

82,846


82,846

Total assets measured at fair value
$
2,639

$
84,943

$

$
87,582

*
The insurance contract invests approximately 54 percent in common stock of large-cap U.S. companies, 11 percent in U.S. Government securities, 10 percent in mortgage-backed securities, 10 percent in corporate bonds and 15 percent in other investments.
 

The Company does not expect to contribute to its defined benefit pension plans and expects to contribute approximately $800,000 to its postretirement benefit plans in 2016.
The following benefit payments, which reflect future service, as appropriate, and expected Medicare Part D subsidies are as follows:
Years
Pension
Benefits

Other
Postretirement Benefits

Expected
Medicare
Part D Subsidy

 
 
(In thousands)

 
2016
$
24,223

$
5,234

$
197

2017
24,680

5,351

191

2018
24,980

5,420

183

2019
25,323

5,441

175

2020
25,700

5,331

168

2021 - 2025
133,029

27,261

688


Nonqualified benefit plans
In addition to the qualified plan defined pension benefits reflected in the table at the beginning of this note, the Company also has unfunded, nonqualified benefit plans for executive officers and certain key management employees that generally provide for defined benefit payments at age 65 following the employee's retirement or to their beneficiaries upon death for a 15-year period. In February 2016, the Company froze the unfunded, nonqualified defined benefit plans to new participants and eliminated upgrades. Vesting for participants not fully vested was retained. The Company's net periodic benefit cost for these plans was $7.1 million, $6.6 million and $7.3 million in 2015, 2014 and 2013, respectively. The total projected benefit obligation for these plans was $110.8 million and $115.6 million at December 31, 2015 and 2014, respectively. The accumulated benefit obligation for these plans was $104.6 million and $108.2 million at December 31, 2015 and 2014, respectively. A weighted average discount rate of 3.77 percent and 3.51 percent at December 31, 2015 and 2014, respectively, and a rate of compensation increase of 4.00 percent and 4.00 percent at December 31, 2015 and 2014, were used to determine benefit obligations. A discount rate of 3.51 percent and 4.32 percent for the years ended December 31, 2015 and 2014, respectively, and a rate of compensation increase of 4.00 percent and 4.00 percent for the years ended December 31, 2015 and 2014, respectively, were used to determine net periodic benefit cost.
The amount of benefit payments for the unfunded, nonqualified benefit plans are expected to aggregate $6.5 million in 2016; $6.7 million in 2017; $7.1 million in 2018; $7.3 million in 2019; $7.8 million in 2020 and $37.7 million for the years 2021 through 2025.
In 2012, the Company established a nonqualified defined contribution plan for certain key management employees. Expenses incurred under this plan for 2015, 2014 and 2013 were $207,000, $104,000 and $25,000, respectively.
The Company had investments of $105.2 million and $101.4 million at December 31, 2015 and 2014, respectively, consisting of equity securities of $54.2 million and $54.9 million, respectively, life insurance carried on plan participants (payable upon the employee's death) of $34.3 million and $32.8 million, respectively, and other investments of $16.7 million and $13.7 million, respectively. The Company anticipates using these investments to satisfy obligations under these plans.
Defined contribution plans
The Company sponsors various defined contribution plans for eligible employees and the costs incurred under these plans were $36.8 million in 2015, $34.4 million in 2014 and $33.2 million in 2013.
Multiemployer plans
The Company contributes to a number of multiemployer defined benefit pension plans under the terms of collective-bargaining agreements that cover its union-represented employees. The risks of participating in these multiemployer plans are different from single-employer plans in the following aspects:
Assets contributed to the MEPP by one employer may be used to provide benefits to employees of other participating employers
If a participating employer stops contributing to the plan, the unfunded obligations of the plan may be borne by the remaining participating employers
If the Company chooses to stop participating in some of its MEPPs, the Company may be required to pay those plans an amount based on the underfunded status of the plan, referred to as a withdrawal liability
The Company's participation in these plans is outlined in the following table. Unless otherwise noted, the most recent Pension Protection Act zone status available in 2015 and 2014 is for the plan's year-end at December 31, 2014, and December 31, 2013, respectively. The zone status is based on information that the Company received from the plan and is certified by the plan's actuary. Among other factors, plans in the red zone are generally less than 65 percent funded, plans in the yellow zone are between 65 percent and 80 percent funded, and plans in the green zone are at least 80 percent funded.
 
EIN/Pension Plan Number
Pension Protection Act Zone Status
FIP/RP Status Pending/Implemented
Contributions
Surcharge Imposed
Expiration Date
of Collective
Bargaining
Agreement
Pension Fund
2015

2014

2015

2014

2013

 
 
 
 
 
(In thousands)
 
 
Edison Pension Plan
93-6061681-001
Green as of 12/31/2015
Green as of 12/31/2014
No
$
5,517

$
9,061

$
6,358

No
12/31/2017
IBEW Local No. 82 Pension Plan
31-6127268-001
Red as of 6/30/2015
Red as of 6/30/2014
Implemented
2,252

1,392

1,284

No
11/29/2015*
IBEW Local No. 246 Pension Plan
34-6582842-001
Yellow as of 5/31/2015
Yellow as of 5/31/2014
Implemented
433

694

1,848

No
10/31/2017
IBEW Local No. 357 Pension Plan A
88-6023284-001
Green
Green
No
1,896

3,575

2,348

No
5/31/2018
IBEW Local 648 Pension Plan
31-6134845-001
Red as of 2/28/2015
Red as of 2/28/2014
Implemented
745

1,110

1,489

No
9/2/2018
Idaho Plumbers and Pipefitters Pension Plan
82-6010346-001
Green as of 5/31/2015
Green as of 5/31/2014
No
1,169

1,125

1,121

No
9/30/2016
Local Union 212 IBEW Pension Trust Fund
31-6127280-001
Yellow as of 4/30/2015
Yellow as of 4/30/2014
Implemented
937

568

531

No
6/5/2016
National Automatic Sprinkler Industry Pension Fund
52-6054620-001
Red as of 12/31/2015
Red as of 12/31/2014
Implemented
677

608

583

No
3/31/2016-
7/31/2018
National Electrical Benefit Fund
53-0181657-001
Green
Green
No
5,271

6,476

5,883

No
6/30/2015*-
11/30/2019
Pension Trust Fund for Operating Engineers
94-6090764-001
Red as of 12/31/2015
Red as of 12/31/2014
Implemented
1,997

1,445

1,510

No
6/15/2015*–
6/30/2016
Operating Engineers Local 800 & WY Contractors Association, Inc. Pension Plan
for Wyoming**
83-6011320-001
Red as of 12/31/2015
Red as of 12/31/2014
Implemented

68

76

No
10/31/2005*
Sheet Metal Workers' Pension Plan of Southern CA, AZ and NV
95-6052257-001
Red as of 12/31/2015
Red as of 12/31/2014
Implemented
714

676

512

No
6/30/2016
Southwest Marine Pension Trust
95-6123404-001
Red
Red
Implemented
26

31

42

No
1/31/2014*–
1/31/2019
Other funds
 
 
 
 
17,478

15,988

15,675

 
 
Total contributions
$
39,112

$
42,817

$
39,260

 
 
*
Plan includes collective bargaining agreements which have expired. The agreements contain provisions that automatically renew the existing contracts in lieu of a new negotiated collective bargaining agreement.
**
The Company withdrew from the plan as of October 26, 2014, as discussed below.
 
The Company was listed in the plans' Forms 5500 as providing more than 5 percent of the total contributions for the following plans and plan years:
Pension Fund
Year Contributions to Plan Exceeded More Than 5 Percent
of Total Contributions (as of December 31 of the Plan's Year-End)
Edison Pension Plan
2014 and 2013
IBEW Local No. 82 Pension Plan
2014 and 2013
Local Union No. 124 IBEW Pension Trust Fund
2014 and 2013
Local Union 212 IBEW Pension Trust Fund
2014 and 2013
IBEW Local Union No. 357 Pension Plan A
2014 and 2013
IBEW Local 573 Pension Plan
2014
IBEW Local 648 Pension Plan
2014 and 2013
Idaho Plumbers and Pipefitters Pension Plan
2014
Minnesota Teamsters Construction Division Pension Fund
2014 and 2013
Operating Engineers Local 800 & WY Contractors Association, Inc. Pension Plan for Wyoming*
2014 and 2013
Pension and Retirement Plan of Plumbers and Pipefitters Union Local No. 525
2014 and 2013

*
The Company withdrew from the plan as of October 26, 2014, as discussed below.
 

On September 24, 2014, Knife River provided notice to the Operating Engineers Local 800 & WY Contractors Association, Inc. Pension Plan for Wyoming that it was withdrawing from the plan effective October 26, 2014. The plan administrator will determine Knife River's withdrawal liability. The Company estimated the withdrawal liability to be approximately $14.0 million at December 31, 2014. In the first quarter of 2015, the Company accrued an additional withdrawal liability of approximately $2.4 million. The total withdrawal liability is currently estimated at $16.4 million. The assessed withdrawal liability for this plan may be significantly different from the current estimate.
The Company also contributes to a number of multiemployer other postretirement plans under the terms of collective-bargaining agreements that cover its union-represented employees. These plans provide benefits such as health insurance, disability insurance and life insurance to retired union employees. Many of the multiemployer other postretirement plans are combined with active multiemployer health and welfare plans. The Company's total contributions to its multiemployer other postretirement plans, which also includes contributions to active multiemployer health and welfare plans, were $31.4 million, $34.6 million and $37.1 million for the years ended December 31, 2015, 2014 and 2013, respectively.
Amounts contributed in 2015, 2014 and 2013 to defined contribution multiemployer plans were $19.5 million, $22.0 million and $20.6 million, respectively.