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EMPLOYEE BENEFIT PLANS (Notes) | 12 Months Ended
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Dec. 31, 2018
EMPLOYEE BENEFIT PLANS [Abstract] |
Pension and Other Postemployment Benefits Disclosure [Text Block] |
12. | EMPLOYEE BENEFIT PLANS
Retirement and Other Postemployment Benefit Plans Retirement Plans - We have a defined benefit pension plan covering nonbargaining-unit employees hired before January 1, 2005, and certain bargaining-unit employees hired before December 15, 2011. Nonbargaining-unit employees hired after December 31, 2004; employees represented by Local No. 304 of the International Brotherhood of Electrical Workers (“IBEW”) hired on or after July 1, 2010; employees represented by the United Steelworkers hired on or after December 15, 2011; and employees who accepted a one-time opportunity to opt out of the defined benefit pension plan are covered by a profit-sharing plan. Certain employees of the Texas Gas Service division are entitled to benefits under a frozen cash-balance pension plan. In addition, we have a supplemental executive retirement plan for the benefit of certain officers. No new participants in the supplemental executive retirement plan have been approved since 2005, and it was formally closed to new participants as of January 1, 2014. We fund our defined benefit pension costs at a level needed to maintain or exceed the minimum funding levels required by the Employee Retirement Income Security Act of 1974, as amended, and the Pension Protection Act of 2006. Other Postemployment Benefit Plans - We sponsor health and welfare plans that provide postemployment medical and life insurance benefits to certain employees who retire with at least five years of service. The postemployment medical plan is contributory based on hire date, age and years of service, with retiree contributions adjusted periodically, and contains other cost-sharing features such as deductibles and coinsurance. Actuarial Assumptions - The following table sets forth the weighted-average assumptions used to determine benefit obligations for pension and postemployment benefits for the periods indicated:
|  | December 31,
|  | 2018 |  | 2017
Discount rate - pension plans |  | 4.40% |  | 3.80%
Discount rate - other postemployment plans |  | 4.40% |  | 3.70%
Compensation increase rate |  | 3.20% - 4.00% |  | 3.25% - 3.35%
The following table sets forth the weighted-average assumptions used by us to determine the periodic benefit costs for the periods indicated:
|  | Years Ended December 31, |
|  | 2018 |  | 2017 |  |  | 2016 |
Discount rate - pension plans |  | 3.80% |  | 4.30% |  |  | 4.75% |
Discount rate - other postemployment plans |  | 3.70% |  | 4.20% |  |  | 4.75%/3.75% | (a)
Expected long-term return on plan assets - pension plans |  | 7.25% |  | 7.75% |  |  | 7.75% |
Expected long-term return on plan assets - other postemployment plans |  | 7.60% |  | 7.60% |  |  | 8.00%/7.75% | (b)
Compensation increase rate |  | 3.25% - 3.35% |  | 3.25% - 3.40% |  |  | 3.35% - 3.40% |
(a) Discount rate for the nine months ended September 30, 2016, and three months ended December 31, 2016, respectively. (b) Expected long-term return on plan assets for the nine months ended September 30, 2016, and three months ended December 31, 2016, respectively. We determine our overall expected long-term rate of return on plan assets, based on our review of historical returns and economic growth models. In 2017, we updated our assumed mortality rates to incorporate the new set of mortality tables issued by the Society of Actuaries. We determine our discount rates annually. We estimate our discount rate based upon a comparison of the expected cash flows associated with our future payments under our defined benefit pension and other postemployment obligations to a hypothetical bond portfolio created using high-quality bonds that closely match expected cash flows. Bond portfolios are developed by selecting a bond for each of the next 60 years based on the maturity dates of the bonds. Bonds selected to be included in the portfolios are only those rated by Moody’s as AA- or better and exclude callable bonds, bonds with less than a minimum issue size, yield outliers and other filtering criteria to remove unsuitable bonds. Regulatory Treatment - The OCC, KCC and regulatory authorities in Texas have approved the recovery of pension costs and other postemployment benefits costs through rates for Oklahoma Natural Gas, Kansas Gas Service and Texas Gas Service, respectively. The costs recovered through rates are based on current funding requirements and the net periodic benefit cost for defined benefit pension and other postemployment costs. Differences, if any, between the expense and the amount recovered through rates would be reflected in earnings, net of authorized deferrals. We historically have recovered defined benefit pension and other postemployment benefit costs through rates. We believe it is probable that regulators will continue to include the net periodic pension and other postemployment benefit costs in our cost of service. Upon adoption of FASB’s ASU 2017-07, we recognized a regulatory asset of $1.5 million, which includes the non-service costs incurred on our pension and other postemployment benefit plans that were capitalized as regulatory assets defined by Topic 980 (Regulated Operations). Obligations and Funded Status - The following table sets forth our defined benefit pension and other postemployment benefit plans, benefit obligations and fair value of plan assets for the periods indicated:
| Pension Benefits |  | Other Postemployment Benefits
| December 31, |  | December 31,
| 2018 |  | 2017 |  | 2018 |  | 2017
Changes in Benefit Obligation | (Thousands of dollars) |  |
Benefit obligation, beginning of period | $ | 993,891 |  |  | $ | 966,531 |  |  | $ | 255,040 |  |  | $ | 243,548 |
Service cost | 12,919 |  |  | 12,176 |  |  | 2,354 |  |  | 2,509 |
Interest cost | 36,801 |  |  | 40,453 |  |  | 9,117 |  |  | 9,890 |
Plan participants’ contributions | — |  |  | — |  |  | 3,563 |  |  | 3,483 |
Actuarial loss (gain) | (42,540 | ) |  | 76,325 |  |  | (31,607 | ) |  | 12,129 |
Benefits paid | (50,561 | ) |  | (55,107 | ) |  | (18,323 | ) |  | (16,690 | )
Plan amendment | — |  |  | — |  |  | — |  |  | 171 |
Settlements | — |  |  | (46,487 | ) |  | — |  |  | — |
Benefit obligation, end of period | 950,510 |  |  | 993,891 |  |  | 220,144 |  |  | 255,040 |
Change in Plan Assets |  |  |  |  |  |  |
Fair value of plan assets, beginning of period | 884,804 |  |  | 739,586 |  |  | 190,226 |  |  | 166,046 |
Actual return (loss) on plan assets | (62,752 | ) |  | 135,056 |  |  | (6,325 | ) |  | 31,228 |
Employer contributions | 42,386 |  |  | 111,936 |  |  | 7,718 |  |  | 6,159 |
Plan participants’ contributions | — |  |  | — |  |  | 3,563 |  |  | 3,483 |
Benefits paid | (50,561 | ) |  | (55,107 | ) |  | (18,323 | ) |  | (16,690 | )
Settlements | 235 |  |  | (46,667 | ) |  | — |  |  | — |
Fair value of assets, end of period | 814,112 |  |  | 884,804 |  |  | 176,859 |  |  | 190,226 |
Balance at December 31 | $ | (136,398 | ) |  | $ | (109,087 | ) |  | $ | (43,285 | ) |  | $ | (64,814 | )
Current liabilities | $ | (962 | ) |  | $ | (963 | ) |  | $ | — |  |  | $ | — |
Noncurrent liabilities | (135,436 | ) |  | (108,124 | ) |  | (43,285 | ) |  | (64,814 | )
Balance at December 31 | $ | (136,398 | ) |  | $ | (109,087 | ) |  | $ | (43,285 | ) |  | $ | (64,814 | )
During 2017, we purchased group annuity contracts for $46.7 million, and transferred to a third-party insurance company liabilities of approximately $46.5 million related to certain participants in our defined benefit pension plan. The accumulated benefit obligation for our defined benefit pension plans was $890.4 million and $936.7 million at December 31, 2018 and 2017, respectively. In 2019, we expect to contribute $1.0 million to our defined benefit pension plans and expect to contribute $3.0 million to our other postemployment benefit plans. There are no plan assets expected to be withdrawn and returned to us in 2019. Components of Net Periodic Benefit Cost - The following tables set forth the components of net periodic benefit cost, prior to regulatory deferrals, for our defined benefit pension and other postemployment benefit plans for the period indicated:
| Pension Benefits
| Year Ended December 31,
| 2018 |  | 2017 |  | 2016
| (Thousands of dollars)
Components of net periodic benefit cost |  |  |  |  |
Service cost | $ | 12,919 |  |  | $ | 12,176 |  |  | $ | 12,055 |
Interest cost (a) | 36,801 |  |  | 40,453 |  |  | 45,550 |
Expected return on assets (a) | (60,579 | ) |  | (58,496 | ) |  | (61,183 | )
Amortization of net loss (a) | 39,913 |  |  | 36,107 |  |  | 35,543 |
Net periodic benefit cost | $ | 29,054 |  |  | $ | 30,240 |  |  | $ | 31,965 |
(a) These amounts, net of any amounts capitalized as a regulatory asset since adoption of ASU 2017-07 on January 1, 2018, have been recognized as other income (expense), net in the Consolidated Statements of Income. See Note 14 for additional detail of our other income (expense), net.
| Other Postemployment Benefits
| Year Ended December 31,
| 2018 |  | 2017 |  | 2016
| (Thousands of dollars)
Components of net periodic benefit cost |  |  |  |  |
Service cost | $ | 2,354 |  |  | $ | 2,509 |  |  | $ | 2,675 |
Interest cost (a) | 9,117 |  |  | 9,890 |  |  | 10,235 |
Expected return on assets (a) | (14,284 | ) |  | (12,590 | ) |  | (12,370 | )
Amortization of unrecognized prior service cost (a) | (4,567 | ) |  | (4,597 | ) |  | (3,316 | )
Amortization of net loss (a) | 3,887 |  |  | 6,484 |  |  | 5,369 |
Net periodic benefit cost (credit) | $ | (3,493 | ) |  | $ | 1,696 |  |  | $ | 2,593 |
(a) These amounts, net of any amounts capitalized as a regulatory asset since adoption of ASU 2017-07 on January 1, 2018, have been recognized as other income (expense), net in the Consolidated Statements of Income. See Note 14 for additional detail of our other income (expense), net. Other Comprehensive Income (Loss) - The following table sets forth the amounts recognized in other comprehensive income (loss), net of regulatory deferrals, related to our defined benefit pension benefits for the period indicated:
| Pension Benefits
| Year Ended December 31,
| 2018 |  | 2017 |  | 2016
| (Thousands of dollars)
Net gain (loss) arising during the period | $ | 1,173 |  |  | $ | (2,101 | ) |  | $ | (1,262 | )
Amortization of loss | 1,082 |  |  | 837 |  |  | 751 |
Deferred income taxes | (848 | ) |  | 486 |  |  | 197 |
Total recognized in other comprehensive income (loss) | $ | 1,407 |  |  | $ | (778 | ) |  | $ | (314 | )
Due to our regulatory deferrals, there were no amounts recognized in other comprehensive income (loss) related to our other postemployment benefits for the periods presented. The tables below set forth the amounts in accumulated other comprehensive loss that had not yet been recognized as components of net periodic benefit expense for the periods indicated:
| Pension Benefits
| December 31,
| 2018 |  | 2017
| (Thousands of dollars)
Accumulated loss | $ | (419,238 | ) |  | $ | (378,595 | )
Accumulated other comprehensive loss before regulatory assets | (419,238 | ) |  | (378,595 | )
Regulatory asset for regulated entities | 412,545 |  |  | 369,647 |
Accumulated other comprehensive loss after regulatory assets | (6,693 | ) |  | (8,948 | )
Deferred income taxes | 2,607 |  |  | 3,455 |
Accumulated other comprehensive loss, net of tax | $ | (4,086 | ) |  | $ | (5,493 | )
| Other Postemployment Benefits
| December 31,
| 2018 |  | 2017
| (Thousands of dollars)
Prior service credit (cost) | $ | 875 |  |  | $ | 5,442 |
Accumulated loss | (34,144 | ) |  | (49,030 | )
Accumulated other comprehensive loss before regulatory assets | $ | (33,269 | ) |  | $ | (43,588 | )
Regulatory asset for regulated entities | 33,269 |  |  | 43,588 |
Accumulated other comprehensive loss after regulatory assets | $ | — |  |  | $ | — |
The following table sets forth the amounts recognized in either accumulated comprehensive income (loss) or regulatory assets expected to be recognized as components of net periodic benefit expense in the next fiscal year:
| Pension Benefits |  | Other Postemployment Benefits
Amounts to be recognized in 2019 | (Thousands of dollars)
Prior service credit (cost) | $ | — |  |  | $ | (673 | )
Actuarial net loss | $ | 33,039 |  |  | $ | 2,244 |
Health Care Cost Trend Rates - The following table sets forth the assumed health care cost-trend rates for the periods indicated:
| 2018 |  | 2017
Health care cost-trend rate assumed for next year | 7.00% |  | 7.00%
Rate to which the cost-trend rate is assumed to decline (the ultimate trend rate) | 5.00% |  | 5.00%
Year that the rate reaches the ultimate trend rate | 2024 |  | 2023
Assumed health care cost-trend rates have a significant effect on the amounts reported for our other postemployment benefit plans. A one percentage point change in assumed health care cost-trend rates would have the following effects:
| One Percentage |  | One Percentage
| Point Increase |  | Point Decrease
| (Millions of dollars)
Effect on total of service and interest cost | $ | 0.2 |  |  | $ | (0.2 | )
Effect on other postemployment benefit obligation | $ | 2.3 |  |  | $ | (2.4 | )
Plan Assets - Our investment strategy is to invest plan assets in accordance with sound investment practices that emphasize long-term fundamentals. The goal of this strategy is to maximize investment returns while managing risk in order to meet the plan’s current and projected financial obligations. To achieve this strategy, we have established a liability-driven investment strategy to change the allocations as the plan reaches certain funded status. The plan’s investments include a diverse blend of various domestic and international equities, investment-grade debt securities which mirror the cash flows of our liability, insurance contracts and alternative investments. The current target allocation for the assets of our defined benefit pension plan is as follows:
Investment-grade bonds | 40.0 | %
U.S. large-cap equities | 18.0 | %
Alternative investments | 14.0 | %
Developed foreign large-cap equities | 10.0 | %
Mid-cap equities | 7.0 | %
Emerging markets equities | 6.0 | %
Small-cap equities | 5.0 | %
Total | 100 | %
As part of our risk management for the plans, minimums and maximums have been set for each of the asset classes listed above. All investment managers for the plan are subject to certain restrictions on the securities they purchase and, with the exception of indexing purposes, are prohibited from owning our stock. The current target allocation for the assets of our other postemployment benefits plan is 30 percent fixed income securities and 70 percent equity securities. The following tables set forth our pension benefits and other postemployment benefits plan assets by fair value category as of the measurement date:
| Pension Benefits
| December 31, 2018
Asset Category | Level 1 | Level 2 | Level 3 | Total
| (Thousands of dollars)
Investments: |  |  |  |
Equity securities (a) | $ | 282,668 |  | $ | 35,870 |  | $ | — |  | $ | 318,538 |
Government obligations | — |  | 69,475 |  | — |  | 69,475 |
Corporate obligations (b) | — |  | 240,900 |  | — |  | 240,900 |
Cash and money market funds (c) | 2,419 |  | 71,991 |  | — |  | 74,410 |
Insurance contracts and group annuity contracts | — |  | — |  | 30,445 |  | 30,445 |
Other investments (d) | — |  | 1,139 |  | 79,205 |  | 80,344 |
Total assets | $ | 285,087 |  | $ | 419,375 |  | $ | 109,650 |  | $ | 814,112 |
(a) - This category represents securities of the various market sectors from diverse industries. (b) - This category represents bonds from diverse industries. (c) - This category is primarily money market funds. (d) - This category represents alternative investments such as hedge funds and other financial instruments.
| Pension Benefits
| December 31, 2017
Asset Category | Level 1 | Level 2 | Level 3 | Total
| (Thousands of dollars)
Investments: |  |  |  |
Equity securities (a) | $ | 301,911 |  | $ | 91,014 |  | $ | — |  | $ | 392,925 |
Government obligations | — |  | 74,596 |  | — |  | 74,596 |
Corporate obligations (b) | — |  | 260,907 |  | — |  | 260,907 |
Cash and money market funds (c) | 21,139 |  | 20,787 |  | — |  | 41,926 |
Insurance contracts and group annuity contracts | — |  | — |  | 35,158 |  | 35,158 |
Other investments (d) | — |  | 585 |  | 78,707 |  | 79,292 |
Total assets | $ | 323,050 |  | $ | 447,889 |  | $ | 113,865 |  | $ | 884,804 |
(a) - This category represents securities of the various market sectors from diverse industries. (b) - This category represents bonds from diverse industries. (c) - This category is primarily money market funds. (d) - This category represents alternative investments such as hedge funds and other financial instruments.
| Other Postemployment Benefits
| December 31, 2018
Asset Category | Level 1 | Level 2 | Level 3 | Total
| (Thousands of dollars)
Investments: |  |  |  |
Equity securities (a) | $ | 58,087 |  | $ | 2,382 |  | $ | — |  | $ | 60,469 |
Government obligations | — |  | 74 |  | — |  | 74 |
Corporate obligations (b) | — |  | 25,857 |  | — |  | 25,857 |
Cash and money market funds (c) | 1,249 |  | 300 |  | — |  | 1,549 |
Insurance contracts and group annuity contracts (d) | — |  | 88,910 |  | — |  | 88,910 |
Total assets | $ | 59,336 |  | $ | 117,523 |  | $ | — |  | $ | 176,859 |
(a) - This category represents securities of the various market sectors from diverse industries. (b) - This category represents bonds from diverse industries. (c) - This category is primarily money market funds. (d) - This category includes equity securities and bonds held in a captive insurance product.
| Other Postemployment Benefits
| December 31, 2017
Asset Category | Level 1 | Level 2 | Level 3 | Total
| (Thousands of dollars)
Investments: |  |  |  |
Equity securities (a) | $ | 63,180 |  | $ | 123 |  | $ | — |  | $ | 63,303 |
Government obligations | — |  | 101 |  | — |  | 101 |
Corporate obligations (b) | — |  | 25,905 |  | — |  | 25,905 |
Cash and money market funds (c) | 4,512 |  | 28 |  | — |  | 4,540 |
Insurance contracts and group annuity contracts | — |  | 96,377 |  | — |  | 96,377 |
Total assets | $ | 67,692 |  | $ | 122,534 |  | $ | — |  | $ | 190,226 |
(a) - This category represents securities of the various market sectors from diverse industries. (b) - This category represents bonds from diverse industries. (c) - This category is primarily money market funds. The following table sets forth the reconciliation of Level 3 fair value measurements of our pension plans for the periods indicated:
| Pension Benefits
| Insurance Contracts |  | Other Investments |  | Total
| (Thousands of dollars)
January 1, 2017 | $ | 45,140 |  |  | $ | 57,352 |  |  | $ | 102,492 |
Net realized and unrealized gains (losses) | 2,569 |  |  | 5,055 |  |  | 7,624 |
Purchases | — |  |  | 16,300 |  |  | 16,300 |
Settlements | (12,551 | ) |  | — |  |  | (12,551 | )
December 31, 2017 | $ | 35,158 |  |  | $ | 78,707 |  |  | $ | 113,865 |
Net realized and unrealized gains (losses) | (611 | ) |  | 496 |  |  | (115 | )
Purchases | — |  |  | — |  |  | — |
Sales and settlements | (4,100 | ) |  | — |  |  | (4,100 | )
December 31, 2018 | $ | 30,445 |  |  | $ | 79,205 |  |  | $ | 109,650 |
Pension and Other Postemployment Benefit Payments - Benefit payments for our defined benefit pension and other postemployment benefit plans for the period ended December 31, 2018 were $50.6 million and $18.3 million, respectively. The following table sets forth the pension benefits and other postemployment benefits payments expected to be paid in 2019-2028:
| Pension Benefits |  | Other Postemployment Benefits
Benefits to be paid in: | (Thousands of dollars)
2019 | $ | 52,368 |  |  | $ | 16,746 |
2020 | $ | 53,332 |  |  | $ | 16,737 |
2021 | $ | 54,245 |  |  | $ | 16,632 |
2022 | $ | 55,474 |  |  | $ | 16,603 |
2023 | $ | 56,477 |  |  | $ | 16,424 |
2024 through 2028 | $ | 295,565 |  |  | $ | 77,769 |
The expected benefits to be paid are based on the same assumptions used to measure our benefit obligation at December 31, 2018 and include estimated future employee service. Other Employee Benefit Plans 401(k) Plan - We have a 401(k) Plan which covers all full-time employees, and employee contributions are discretionary. We match 100 percent of each participant’s eligible contribution up to 6 percent of eligible compensation, subject to certain limits. Our contributions made to the plan were $12.1 million, $11.7 million and $10.8 million in 2018, 2017 and 2016, respectively. Profit Sharing Plan - We have a profit sharing plan for all employees who do not participate in our defined benefit pension plan. We plan to make a contribution to the profit sharing plan each quarter equal to 1 percent of each participant’s eligible compensation during the quarter. Additional discretionary employer contributions may be made at the end of each year. Employee contributions are not allowed under the plan. Our contributions made to the plan were $7.4 million, $8.1 million and $6.0 million in 2018, 2017 and 2016, respectively.

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- Definition EMPLOYEE BENEFIT PLANS [Abstract] + References No definition available. + Details
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- Definition The entire disclosure for pension and other postretirement benefits. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -URI http://asc.fasb.org/topic&trid=2235017 + Details
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