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Employee Benefit Plans
12 Months Ended
Dec. 31, 2019
Retirement Benefits [Abstract]  
Employee Benefit Plans
(14)          Employee Benefit Plans

Pension and Other Postretirement Benefit Plans

We sponsor and/or contribute to pension and postretirement health care and life insurance benefit plans for eligible employees. The pension plan for our South Dakota and Nebraska employees is referred to as the NorthWestern Corporation plan, and the pension plan for our Montana employees is referred to as the NorthWestern Energy plan, and collectively they are referred to as the Plans. We utilize a number of accounting mechanisms that reduce the volatility of reported pension costs. Differences between actuarial assumptions and actual plan results are deferred and are recognized into earnings only when the accumulated differences exceed 10% of the greater of the projected benefit obligation or the market-related value of plan assets. If necessary, the excess is amortized over the average remaining service period of active employees. The Plan’s funded
status is recognized as an asset or liability in our Consolidated Financial Statements. See Note 4 - Regulatory Assets and Liabilities, for further discussion on how these costs are recovered through rates charged to our customers.

Benefit Obligation and Funded Status

Following is a reconciliation of the changes in plan benefit obligations and fair value of plan assets, and a statement of the funded status (in thousands):
 
Pension Benefits
 
Other Postretirement Benefits
 
December 31,
 
December 31,
 
2019
 
2018
 
2019
 
2018
Change in benefit obligation:
 
 
 
 
 
 
 
Obligation at beginning of period
$
649,626

 
$
696,796

 
$
20,611

 
$
22,921

Service cost
9,637

 
11,776

 
331

 
398

Interest cost
26,488

 
24,420

 
609

 
578

Actuarial loss (gain)
83,364

 
(53,496
)
 
997

 
(1,903
)
Settlements
(4,065
)
 

 
390

 
390

Benefits paid
(29,486
)
 
(29,870
)
 
(2,666
)
 
(1,773
)
Benefit Obligation at End of Period
$
735,564

 
$
649,626

 
$
20,272

 
$
20,611

Change in Fair Value of Plan Assets:
 
 
 
 
 
 
 
Fair value of plan assets at beginning of period
$
525,310

 
$
586,508

 
$
18,670

 
$
20,380

Return on plan assets
107,041

 
(40,528
)
 
3,805

 
(866
)
Employer contributions
10,200

 
9,200

 
1,670

 
929

Settlements
(4,065
)
 

 

 

Benefits paid
(29,486
)
 
(29,870
)
 
(2,666
)
 
(1,773
)
Fair value of plan assets at end of period
$
609,000

 
$
525,310

 
$
21,479

 
$
18,670

Funded Status
$
(126,564
)
 
$
(124,316
)
 
$
1,207

 
$
(1,941
)
 
 
 
 
 
 
 
 
Amounts Recognized in the Balance Sheet Consist of:
 
 
 
 
 
 
 
Noncurrent asset
4,333

 
2,672

 
7,783

 
4,565

Total Assets
4,333

 
2,672

 
7,783

 
4,565

Current liability
(11,401
)
 

 
(2,113
)
 
(2,271
)
Noncurrent liability
(119,496
)
 
(126,988
)
 
(4,463
)
 
(4,235
)
Total Liabilities
(130,897
)
 
(126,988
)
 
(6,576
)
 
(6,506
)
Net amount recognized
$
(126,564
)
 
$
(124,316
)
 
$
1,207

 
$
(1,941
)
 
 
 
 
 
 
 
 
Amounts Recognized in Regulatory Assets Consist of:
 
 
 
 
 
 
 
Prior service credit

 

 
5,890

 
7,922

Net actuarial (loss) gain
(111,449
)
 
(116,425
)
 
259

 
(1,910
)
Amounts recognized in AOCL consist of:
 
 
 
 
 
 
 
Prior service cost

 

 
(397
)
 
(548
)
Net actuarial gain

 

 
934

 
1,260

Total
$
(111,449
)
 
$
(116,425
)
 
$
6,686

 
$
6,724


The actuarial gain/loss is primarily due to the change in discount rate assumption and actual asset returns compared with expected amounts.

The total projected benefit obligation and fair value of plan assets for the pension plans with accumulated benefit obligations in excess of plan assets were as follows (in millions):
 
NorthWestern Energy Pension Plan
 
December 31,
2019
 
2018
Projected benefit obligation
$
675.5

 
$
592.5

Accumulated benefit obligation
675.5

 
592.5

Fair value of plan assets
545.8

 
466.7

 ____________________
As of December 31, 2019, the fair value of the NorthWestern Corporation pension plan assets exceed the total projected and accumulated benefit obligation and are therefore excluded from this table.

Net Periodic Cost (Credit)

The components of the net costs (credits) for our pension and other postretirement plans are as follows (in thousands):
 
Pension Benefits
 
Other Postretirement Benefits
 
December 31,
 
December 31,
 
2019
 
2018
 
2017
 
2019
 
2018
 
2017
Components of Net Periodic Benefit Cost
 
 
 
 
 
 
 
 
 
 
 
Service cost
$
9,637

 
$
11,776

 
$
10,994

 
$
331

 
$
398

 
$
456

Interest cost
26,488

 
24,420

 
25,633

 
609

 
578

 
715

Expected return on plan assets
(25,443
)
 
(28,207
)
 
(23,964
)
 
(869
)
 
(954
)
 
(846
)
Amortization of prior service cost (credit)

 
4

 
4

 
(1,882
)
 
(1,882
)
 
(1,882
)
Recognized actuarial loss (gain)
6,544

 
4,360

 
7,837

 
(96
)
 
(79
)
 
318

Settlement loss recognized
198

 

 

 
390

 
390

 
390

Net Periodic Benefit Cost (Credit)
$
17,424

 
$
12,353

 
$
20,504

 
$
(1,517
)
 
$
(1,549
)
 
$
(849
)
 
 
 
 
 
 
 
 
 
 
 
 
Regulatory deferral of net periodic benefit cost (1)
(7,510
)
 
(4,057
)
 
(11,751
)
 

 

 

Previously deferred costs recognized (1)
728

 
243

 
724

 
931

 
913

 
1,153

Amount Recognized in Income
$
10,642

 
$
8,539

 
$
9,477

 
$
(586
)
 
$
(636
)
 
$
304

 
 
 
 
 
 
 
 
 
 
 
 
Income Statement Presentation
 
 
 
 
 
 
 
 
 
 
Operating, general and administrative expense
2,125

 
7,719

 
(757
)
 
331

 
398

 
457

Other income (expense), net
8,517

 
820

 
10,234

 
(917
)
 
(1,034
)
 
(153
)
Amount Recognized in Income
$
10,642

 
$
8,539

 
$
9,477

 
$
(586
)
 
$
(636
)
 
$
304

 
 
 
 
 
 
 
 
 
 
 
 

___________________________
(1) Net periodic benefit costs for pension and postretirement benefit plans are recognized for financial reporting based on the authorization of each regulatory jurisdiction in which we operate. A portion of these costs are recorded in regulatory assets and recognized in the Consolidated Statements of Income as those costs are recovered through customer rates.

For purposes of calculating the expected return on pension plan assets, the market-related value of assets is used, which is based upon fair value. The difference between actual plan asset returns and estimated plan asset returns are amortized equally over a period not to exceed five years.

Actuarial Assumptions

The measurement dates used to determine pension and other postretirement benefit measurements for the plans are December 31, 2019 and 2018. The actuarial assumptions used to compute net periodic pension cost and postretirement benefit cost are based upon information available as of the beginning of the year, specifically, market interest rates, past experience and management's best estimate of future economic conditions. Changes in these assumptions may impact future benefit costs and obligations. In computing future costs and obligations, we must make assumptions about such things as employee mortality and turnover, expected salary and wage increases, discount rate, expected return on plan assets, and expected future cost increases. Two of these assumptions have the most impact on the level of cost: (1) discount rate and (2) expected rate of return on plan assets.

On an annual basis, we set the discount rate using a yield curve analysis. This analysis includes constructing a hypothetical bond portfolio whose cash flow from coupons and maturities matches the year-by-year, projected benefit cash flow from our plans. The decrease in discount rate during 2019 increased our projected benefit obligation by approximately $87.6 million.

In determining the expected long-term rate of return on plan assets, we review historical returns, the future expectations for returns for each asset class weighted by the target asset allocation of the pension and postretirement portfolios, and long-term inflation assumptions. Based on the target asset allocation for our pension assets and future expectations for asset returns, we decreased our long term rate of return on assets assumption for NorthWestern Energy Pension Plan to 4.49% and decreased our assumption on the NorthWestern Corporation Pension Plan to 3.45% for 2020.

The weighted-average assumptions used in calculating the preceding information are as follows:
 
Pension Benefits
 
Other Postretirement Benefits
 
 
December 31,
 
December 31,
 
 
2019
 
2018
 
2017
 
2019
 
2018
 
2017
 
Discount rate
3.10-3.20
%
4.15-4.20
%
3.50-3.60
%
2.80
%
3.90-3.95
%
3.20-3.30
%
Expected rate of return on assets
4.23-5.06
 
4.47-4.97
 
4.70
 
4.79
 
4.82
 
4.70
 
Long-term rate of increase in compensation levels (non-union)
2.84
 
2.84
 
2.89
 
2.84
 
2.84
 
2.89
 
Long-term rate of increase in compensation levels (union)
2.00
 
2.03
 
2.03
 
2.00
 
2.03
 
2.03
 
Interest crediting rate
3.60-6.00
 
4.00-6.00
 
4.00-6.00
 
N/A
 
N/A
 
N/A
 


The postretirement benefit obligation is calculated assuming that health care costs increase by a 5.00% fixed rate. The company contribution toward the premium cost is capped, therefore future health care cost trend rates are expected to have a minimal impact on company costs and the accumulated postretirement benefit obligation.

Investment Strategy

Our investment goals with respect to managing the pension and other postretirement assets are to meet current and future benefit payment needs while maximizing total investment returns (income and appreciation) after inflation within the constraints of diversification, prudent risk taking, and the Prudent Man Rule of the Employee Retirement Income Security Act of 1974. Each plan is diversified across asset classes to achieve optimal balance between risk and return and between income and growth through capital appreciation. Our investment philosophy is based on the following:

Each plan should be substantially invested as long-term cash holdings reduce long-term rates of return;
It is prudent to diversify each plan across the major asset classes;
Equity investments provide greater long-term returns than fixed income investments, although with greater short-term volatility;
Fixed income investments of the plans should strongly correlate with the interest rate sensitivity of the plan’s aggregate liabilities in order to hedge the risk of change in interest rates negatively impacting the overall funded status;
Allocation to foreign equities increases the portfolio diversification and thereby decreases portfolio risk while providing for the potential for enhanced long-term returns;
Active management can reduce portfolio risk and potentially add value through security selection strategies;
A portion of plan assets should be allocated to passive, indexed management funds to provide for greater diversification and lower cost; and
It is appropriate to retain more than one investment manager, provided that such managers offer asset class or style diversification.

Investment risk is measured and monitored on an ongoing basis through quarterly investment portfolio reviews, annual liability measurements, and periodic asset/liability studies.

The most important component of an investment strategy is the portfolio asset mix, or the allocation between the various classes of securities available. The mix of assets is based on an optimization study that identifies asset allocation targets in order to achieve the maximum return for an acceptable level of risk, while minimizing the expected contributions and pension and postretirement expense. In the optimization study, assumptions are formulated about characteristics, such as expected asset class investment returns, volatility (risk), and correlation coefficients among the various asset classes, and making adjustments to reflect future conditions expected to prevail over the study period. Based on this, the target asset allocation established, within an allowable range of plus or minus 5%, is as follows:
 
NorthWestern Energy Pension
 
NorthWestern Corporation Pension
 
NorthWestern Energy
Health and Welfare
 
December 31,
 
December 31,
 
December 31,
 
2019
 
2018
 
2019
 
2018
 
2019
 
2018
Domestic debt securities
55.0
%
 
55.0
%
 
80.0
%
 
75.0
%
 
40.0
%
 
40.0
%
International debt securities
4.0

 
4.0

 
2.0

 
2.5

 

 

Domestic equity securities
16.5

 
16.5

 
7.2

 
9.0

 
50.0

 
50.0

International equity securities
24.5

 
24.5

 
10.8

 
13.5

 
10.0

 
10.0



The actual allocation by plan is as follows:
 
NorthWestern Energy Pension
 
NorthWestern Corporation Pension
 
NorthWestern Energy
Health and Welfare
 
December 31,
 
December 31,
 
December 31,
2019
 
2018
 
2019
 
2018
 
2019
 
2018
Cash and cash equivalents
%
 
0.1
%
 
0.9
%
 
%
 
1.0
%
 
1.0
%
Domestic debt securities
53.8

 
57.5

 
77.0

 
81.3

 
37.8

 
40.8

International debt securities
4.0

 
4.4

 
2.6

 
2.6

 

 

Domestic equity securities
16.8

 
15.0

 
8.1

 
6.3

 
52.4

 
49.1

International equity securities
25.4

 
23.0

 
11.4

 
9.8

 
8.8

 
9.1

 
100.0
%
 
100.0
%
 
100.0
%
 
100.0
%
 
100.0
%
 
100.0
%


Generally, the asset mix will be rebalanced to the target mix as individual portfolios approach their minimum or maximum levels. Debt securities consist of U.S. and international instruments. Core domestic portfolios can be invested in government, corporate, asset-backed and mortgage-backed obligation securities. While the portfolio may invest in high yield securities, the average quality must be rated at least “investment grade" by rating agencies. Performance of fixed income investments is measured by both traditional investment benchmarks as well as relative changes in the present value of the plan's liabilities. Equity investments consist primarily of U.S. stocks including large, mid and small cap stocks, which are diversified across investment styles such as growth and value. We also invest in international equities with exposure to developing and emerging markets. Derivatives, options and futures are permitted for the purpose of reducing risk but may not be used for speculative purposes.

Our plan assets are primarily invested in common collective trusts (CCTs), which are invested in equity and fixed income securities. In accordance with our investment policy, these pooled investment funds must have an adequate asset base relative to their asset class and be invested in a diversified manner and have a minimum of three years of verified investment performance experience or verified portfolio manager investment experience in a particular investment strategy and have management and oversight by an investment advisor registered with the SEC. Investments in a collective investment vehicle are valued by multiplying the investee company’s net asset value per share with the number of units or shares owned at the valuation date. Net asset value per share is determined by the trustee. Investments held by the CCT, including collateral invested for securities on loan, are valued on the basis of valuations furnished by a pricing service approved by the CCT’s investment manager, which determines valuations using methods based on quoted closing market prices on national securities exchanges, or at fair value as determined in good faith by the CCT’s investment manager if applicable. The funds do not
contain any redemption restrictions. The direct holding of NorthWestern Corporation stock is not permitted; however, any holding in a diversified mutual fund or collective investment fund is permitted. During 2019, due to proposed changes in the John Hancock participating group annuity contract held by the NorthWestern Corporation plan, we elected to discontinue the contract effective January 1, 2020.

Cash Flows

In accordance with the Pension Protection Act of 2006 (PPA), and the relief provisions of the Worker, Retiree, and Employer Recovery Act of 2008 (WRERA), we are required to meet minimum funding levels in order to avoid required contributions and benefit restrictions. We have elected to use asset smoothing provided by the WRERA, which allows the use of asset averaging, including expected returns (subject to certain limitations), for a 24-month period in the determination of funding requirements. We expect to continue to make contributions to the pension plans in 2019 and future years that reflect the minimum requirements and discretionary amounts consistent with the amounts recovered in rates. Additional legislative or regulatory measures, as well as fluctuations in financial market conditions, may impact our funding requirements.

Due to the regulatory treatment of pension costs in Montana, pension expense for 2019, 2018 and 2017 was based on actual contributions to the plan. Annual contributions to each of the pension plans are as follows (in thousands):
 
2019
 
2018
 
2017
NorthWestern Energy Pension Plan (MT)
$
9,000

 
$
8,000

 
$
8,000

NorthWestern Corporation Pension Plan (SD and NE)
1,200

 
1,200

 
1,200

 
$
10,200

 
$
9,200

 
$
9,200



We estimate the plans will make future benefit payments to participants as follows (in thousands):
 
Pension Benefits
 
Other Postretirement Benefits
2020
$
33,310

 
$
3,025

2021
34,823

 
2,934

2022
36,154

 
2,501

2023
37,605

 
2,337

2024
39,084

 
1,843

2025-2029
207,765

 
5,851


Defined Contribution Plan

Our defined contribution plan permits employees to defer receipt of compensation as provided in Section 401(k) of the Internal Revenue Code. Under the plan, employees may elect to direct a percentage of their gross compensation to be contributed to the plan. We contribute various percentage amounts of the employee's gross compensation contributed to the plan. Matching contributions for the years ended December 31, 2019, 2018 and 2017 were $11.0 million, $10.6 million, and $10.0 million, respectively.