Employee and Retiree Benefit Plans (Tables)

12 Months Ended

Dec. 31, 2019

Defined Benefit Plan Disclosure [Line Items]

Plans' Benefit Obligations and Fair Value of Assets and Statement of Funded Status

The tables that follow provide a reconciliation of the changes in the plans’ benefit obligations and fair value of assets for the years ended December 31, 2019 and 2018 and a statement of the funded status as of December 31, 2019 and 2018.

	Pension Benefits					Other Postretirement Benefits
(Thousands of dollars)	2019			2018		2019		2018
Change in benefit obligation
Obligation at January 1	$	777,645		881,932		94,779		106,276
Service cost	7,964			8,994		1,559		1,965
Interest cost	27,835			26,168		3,864		3,427
Participant contributions	11			—		1,930		2,104
Actuarial loss (gain)	103,374			(57,378	)	10,503		(13,778	)
Medicare Part D subsidy	—			—		234		325
Exchange rate changes	7,687			(12,742	)	30		(67	)
Benefits paid	(41,247		)	(41,132	)	(4,498	)	(5,473	)
Prior Service Cost	—			737		—		—
Other	—			(28,934	)	—		—
Obligation at December 31	883,269			777,645		108,401		94,779
Change in plan assets
Fair value of plan assets at January 1	487,094			563,825		—		—
Actual return on plan assets	70,893			(18,951	)	—		—
Employer contributions	25,915			24,357		2,333		3,044
Participant contributions	11			—		1,930		2,104
Medicare Part D subsidy	—			—		234		325
Exchange rate changes	7,328			(12,071	)	—		—
Benefits paid	(41,247		)	(41,132	)	(4,497	)	(5,473	)
Other	(2,510		)	(28,934	)	—		—
Fair value of plan assets at December 31	547,484			487,094		—		—
Funded status and amounts recognized in the Consolidated Balance Sheets at December 31
Deferred charges and other assets	5,353			11,039		—		—
Other accrued liabilities	(8,810		)	(9,175	)	(5,234	)	(5,101	)
Deferred credits and other liabilities	(332,328		)	(292,415	)	(103,167	)	(89,678	)
Fund Status and net plan liability recognized at December 31	$	(335,785	)	(290,551	)	(108,401	)	(94,779	)

Amounts Included in Accumulated Other Comprehensive Income Not Recognized in Net Periodic Benefit Expense

At December 31, 2019, amounts included in Accumulated other comprehensive loss (AOCL) in the Consolidated Balance Sheets, before reduction for associated deferred income taxes, which have not been recognized in net periodic benefit expense are shown in the following table.

(Thousands of dollars)	Pension Benefits			Other Postretirement Benefits
Net actuarial gain (loss)	$	(269,391	)	3,307
Prior service cost	(4,090		)	—
	$	(273,481	)	3,307

Amounts Included in Accumulated Other Comprehensive Income Expected to be Amortized into Net Periodic Benefit Expense

Amounts included in AOCL at December 31, 2019 that are expected to be amortized into net periodic benefit expense during 2020 are shown in the following table.

(Thousands of dollars)	Pension Benefits			Other Postretirement Benefits
Net actuarial loss	$	(17,096	)	—
Prior service cost	(734		)	—
	$	(17,830	)	—

Projected Benefit Obligations, Accumulated Benefit Obligations and Fair Value of Plan Assets

The table that follows includes projected benefit obligations, accumulated benefit obligations and fair value of plan assets for plans where the accumulated benefit obligation exceeded the fair value of plan assets.

	Projected Benefit Obligations			Accumulated Benefit Obligations		Fair Value of Plan Assets
(Thousands of dollars)	2019		2018	2019	2018	2019	2018
Funded qualified plans where accumulated benefit obligation exceeds fair value of plan assets	$	688,249	457,446	676,177	447,793	525,108	316,543
Unfunded nonqualified and directors’ plans where accumulated benefit obligation exceeds fair value of plan assets	177,999		158,228	171,934	150,586	—	—
Unfunded other postretirement plans	108,401		94,808	108,401	94,808	—	—

Components of Net Periodic Benefit Expense

The table that follows provides the components of net periodic benefit expense for each of the three years ended December 31, 2019.

	Pension Benefits							Other Postretirement Benefits
(Thousands of dollars)	2019			2018		2017		2019		2018		2017
Service cost	$	7,964		8,994		8,279		1,559		1,965		1,601
Interest cost	27,835			26,168		27,047		3,864		3,427		3,444
Expected return on plan assets	(25,719		)	(29,236	)	(28,941	)	—		—		—
Amortization of prior service cost (credit)	964			1,021		1,026		—		(38	)	(74	)
Recognized actuarial loss	14,106			21,893		16,691		(193	)	—		—
Net periodic benefit expense	$	25,150		28,840		24,102		5,230		5,354		4,971

Weighted-Average Assumptions used in Measurement of Benefit Obligations and Net Periodic Benefit Expense

The following table provides the weighted-average assumptions used in the measurement of the Company’s benefit obligations at December 31, 2019 and 2018 and net periodic benefit expense for 2019 and 2018 .

	Benefit Obligations								Net Periodic Benefit Expense
	Pension Benefits				Other Postretirement Benefits				Pension Benefits				Other Postretirement Benefits
	December 31,				December 31,				Year				Year
	2019		2018		2019		2018		2019		2018		2019		2018
Discount rate	3.85	%	4.07	%	3.42	%	3.73	%	3.35	%	3.54	%	4.42	%	4.32	%
Expected return on plan assets	5.05	%	5.37	%	—		—		5.05	%	5.37	%	—		—
Rate of compensation increase	3.28	%	3.28	%	—		—		3.52	%	3.52	%	—		—

Benefit Payments Expected to be Paid in Future Years

Benefit payments, reflecting expected future service as appropriate, which are expected to be paid in future years from the assets of the plans or by the Company are shown in the following table.

(Thousands of dollars)	Pension Benefits		Other Postretirement Benefits
2020	$	42,399	5,233
2021	43,500		5,360
2022	44,824		5,428
2023	44,850		5,421
2024	45,557		5,505
2025-2030	233,751		27,847

One Percent Change in Assumed Health Care Cost Trend Rates

Assumed health care cost trend rates have a significant effect on the expense and obligation reported for the postretirement benefit plan.  A one percent change in assumed health care cost trend rates would have the following effects.

(Thousands of dollars)	1% Increase		1% Decrease
Effect on total service and interest cost components of net periodic postretirement benefit expense for the year ended December 31	$	930	(737	)
Effect on the health care component of the accumulated postretirement benefit obligation at December 31	15,257		(12,291	)

Weighted Average Asset Allocation for Funded Pension Benefit Plans

The weighted average asset allocation for the Company’s funded pension benefit plans at December 31, 2019 and 2018 are presented in the following table.

	December 31,
	2019		2018
Equity securities	54.9	%	56.0	%
Fixed income securities	26.2		42.2
Alternatives	17.3		—
Cash equivalents	1.6		1.8
	100.0	%	100.0	%

The following table provides the asset allocation of each plan on December 31, 2019.

	Allocation of Plan Assets
	Domestic Plan		Canadian Plan		U.K. Plan
	Target	Allocation at	Target	Allocation at	Target	Allocation at
	Allocation	December 31, 2019	Allocation	December 31, 2019	Allocation	December 31, 2019
Equity securities	40-70%	54.0%	28-38%	34.5%	N/A	59.2%
Fixed income securities	25-60%	27.8%	60-70%	63.5%	N/A	18.4%
Alternatives	0-20%	16.9%	—%	—%	N/A	20.2%
Cash and equivalents	0-15%	1.3%	0-10%	2.0%	N/A	2.2%

Fair Value Measurements of Retirement Plan Assets

At December 31, 2019, the fair value measurements of retirement plan assets within the fair value hierarchy are included in the table that follows.

			Fair Value Measurements Using
(Thousands of dollars)	Fair Value at December 31, 2019		Quoted Prices in Active Markets for Identical Assets (Level 1)	Significant Other Observable Inputs (Level 2)	Significant Unobservable Inputs (Level 3)
Domestic Plans
Equity securities:
U.S. core equity	$	63,169	63,169	—	—
U.S. small/midcap	26,062		26,062	—	—
Hedged funds and other alternative strategies	58,864		—	—	58,864
International commingled trust fund	73,783		924	55,798	17,061
Emerging market commingled equity fund	25,911		8,011	17,900	—
Fixed income securities:
U.S. fixed income	88,525		—	88,525	—
International commingled trust fund	8,720		—	8,720	—
Cash and equivalents	4,485		4,485	—	—
Total Domestic Plans	349,519		102,651	170,943	75,925
Foreign Plans
Equity securities funds	68,878		—	68,840	—
Fixed income securities funds	46,582		—	46,390	—
Diversified pooled fund	42,582		—	42,582	—
Other	35,661		—	—	35,661
Cash and equivalents	4,262		—	4,256	—
Total Foreign Plans	197,965		—	162,068	35,661
Total	$	547,484	102,651	333,011	111,586

At December 31, 2018, the fair value measurements of retirement plan assets within the fair value hierarchy are included in the table that follows.

			Fair Value Measurements Using
(Thousands of dollars)	Fair Value at December 31, 2018		Quoted Prices in Active Markets for Identical Assets (Level 1)	Significant Other Observable Inputs (Level 2)	Significant Unobservable Inputs (Level 3)
Domestic Plans
Equity securities:
U.S. core equity	$	62,105	62,105	—	—
U.S. small/midcap	19,436		19,436	—	—
Hedged funds and other alternative strategies	45,844		—	10,789	35,055
International commingled trust fund	63,089		—	63,089	—
Emerging market commingled equity fund	15,355		—	15,355	—
Fixed income securities:
U.S. fixed income	87,526		—	87,526	—
International commingled trust fund	13,274		—	13,274	—
Emerging market mutual fund	4,570		—	4,570	—
Cash and equivalents	5,344		5,344	—	—
Total Domestic Plans	316,543		86,885	194,603	35,055
Foreign Plans
Equity securities funds	67,165		—	67,165	—
Fixed income securities funds	89,417		—	89,417	—
Diversified pooled fund	10,762		—	10,762	—
Cash and equivalents	3,207		—	3,207	—
Total Foreign Plans	170,551		—	170,551	—
Total	$	487,094	86,885	365,154	35,055

Effects of Fair Value Measurements Using Significant Unobservable Inputs on Changes in Level 3 Plan Assets

The effects of fair value measurements using significant unobservable inputs on changes in Level 3 plan assets are outlined below:

(Thousands of dollars)	Hedged Funds and Other Alternative Strategies
Total at December 31, 2017	$	37,950
Actual return on plan assets:
Relating to assets held at the reporting date	(2,921		)
Total at December 31, 2018	35,029
Actual return on plan assets:
Relating to assets held at the reporting date	20,811
Purchases, sales and settlements	55,746
Total at December 31, 2019	$	111,586

Foreign Plans

Defined Benefit Plan Disclosure [Line Items]

Plans' Benefit Obligations and Fair Value of Assets and Statement of Funded Status

	Pension Benefits				Other Postretirement Benefits
(Thousands of dollars)	2019			2018	2019	2018
Benefit obligation at December 31	$	209,923		173,860	387	812
Fair value of plan assets at December 31	197,965			170,551	—	—
Net plan liabilities recognized	(11,957		)	3,309	387	812
Net periodic benefit expense (benefit)	(933		)	3,983	147	146