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v3.23.2

Pension and other post-employment benefits - Components of Net Benefit Costs for Pension Plans and OPEB Recorded as Part of Administrative Expenses (Detail) - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2023 | Jun. 30, 2022 | Jun. 30, 2023 | Jun. 30, 2022
Non-service costs |  |  |  |
Non-service costs | $ 5,306 | $ 2,258 | $ 10,267 | $ 4,836
Pension benefits |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Service cost | 3,166 | 4,532 | 6,093 | 8,388
Non-service costs |  |  |  |
Interest cost | 7,906 | 6,778 | 16,299 | 12,841
Expected return on plan assets | (7,947) | (10,519) | (16,263) | (20,843)
Amortization of net actuarial losses (gains) | (71) | 1,257 | (195) | 2,046
Amortization of prior service credits | (373) | (389) | (746) | (792)
Impact of regulatory accounts | 4,588 | 4,664 | 8,683 | 11,002
Non-service costs | 4,103 | 1,791 | 7,778 | 4,254
Net benefit cost | 7,269 | 6,323 | 13,871 | 12,642
OPEB |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Service cost | 902 | 1,554 | 1,891 | 3,109
Non-service costs |  |  |  |
Interest cost | 2,891 | 2,282 | 6,329 | 4,641
Expected return on plan assets | (2,331) | (2,841) | (5,077) | (5,682)
Amortization of net actuarial losses (gains) | (561) | (86) | (1,122) | (172)
Amortization of prior service credits | (213) | 6 | (426) | 12
Impact of regulatory accounts | 1,417 | 1,106 | 2,785 | 1,783
Non-service costs | 1,203 | 467 | 2,489 | 582
Net benefit cost | $ 2,105 | $ 2,021 | $ 4,380 | $ 3,691

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- Definition Amount of gain (loss) recognized in net periodic benefit (cost) credit of defined benefit plan. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 17 -Publisher FASB -URI https://asc.fasb.org//1943274/2147480482/715-20-55-17 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 3A -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480535/715-20-45-3A Reference 3: http://www.xbrl.org/2003/role/exampleRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 18 -Publisher FASB -URI https://asc.fasb.org//1943274/2147480482/715-20-55-18 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (h)(4) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a)(4) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-6 + Details
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- Definition Amount of expected return (loss) recognized in net periodic benefit (cost) credit, calculated based on expected long-term rate of return and market-related value of plan assets of defined benefit plan. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 17 -Publisher FASB -URI https://asc.fasb.org//1943274/2147480482/715-20-55-17 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 3A -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480535/715-20-45-3A Reference 3: http://www.xbrl.org/2003/role/exampleRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 18 -Publisher FASB -URI https://asc.fasb.org//1943274/2147480482/715-20-55-18 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (h)(3) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a)(3) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-6 + Details
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