Retirement Benefits (Tables)

9 Months Ended

Sep. 30, 2021

Retirement Benefits [Abstract]

Schedule of Net Benefit Costs

The following tables summarize the Company’s net periodic benefit cost for the three and nine months ended September 30, 2021 and 2020:

Puget Energy	Qualified Pension Benefits				SERP Pension Benefits				Other Benefits
	Three Months Ended September 30,
(Dollars in Thousands)	2021		2020		2021		2020		2021		2020
Components of net periodic benefit cost:
Service cost	$	6,722	$	6,084	$	115	$	176	$	34	$	47
Interest cost	5,595		6,295		293		362		72		92
Expected return on plan assets	(12,060)		(12,476)		—		—		(84)		(97)
Amortization of prior service cost	(476)		(393)		87		87		2		—
Amortization of net loss (gain)	2,951		2,040		588		512		(10)		(20)
Net periodic benefit cost	$	2,732	$	1,550	$	1,083	$	1,137	$	14	$	22

Puget Energy	Qualified Pension Benefits				SERP Pension Benefits				Other Benefits
	Nine Months Ended September 30,
(Dollars in Thousands)	2021		2020		2021		2020		2021		2020
Components of net periodic benefit cost:
Service cost	$	20,166	$	18,253	$	344	$	580	$	117	$	142
Interest cost	16,786		18,885		879		1,102		226		276
Expected return on plan assets	(36,179)		(37,427)		—		—		(266)		(292)
Amortization of prior service cost	(1,428)		(1,180)		262		262		5		—
Amortization of net loss (gain)	8,852		6,120		1,763		1,610		(30)		(61)
Net periodic benefit cost	$	8,197	$	4,651	$	3,248	$	3,554	$	52	$	65

Puget Sound Energy	Qualified Pension Benefits				SERP Pension Benefits				Other Benefits
	Three Months Ended September 30,
(Dollars in Thousands)	2021		2020		2021		2020		2021		2020
Components of net periodic benefit cost:
Service cost	$	6,722	$	6,084	$	115	$	176	$	34	$	47
Interest cost	5,595		6,295		293		362		72		92
Expected return on plan assets	(12,061)		(12,478)		—		—		(84)		(97)
Amortization of prior service cost	(378)		(393)		87		87		2		—
Amortization of net loss (gain)	5,465		4,761		635		575		(11)		(34)
Net periodic benefit cost	$	5,343	$	4,269	$	1,130	$	1,200	$	13	$	8

Puget Sound Energy	Qualified Pension Benefits				SERP Pension Benefits				Other Benefits
	Nine Months Ended September 30,
(Dollars in Thousands)	2021		2020		2021		2020		2021		2020
Components of net periodic benefit cost:
Service cost	$	20,166	$	18,253	$	344	$	580	$	117	$	142
Interest cost	16,786		18,885		879		1,102		226		276
Expected return on plan assets	(36,182)		(37,433)		—		—		(266)		(292)
Amortization of prior service cost	(1,135)		(1,180)		262		262		5		—
Amortization of net loss (gain)	16,396		14,283		1,906		1,810		(40)		(103)
Net periodic benefit cost	$	16,031	$	12,808	$	3,391	$	3,754	$	42	$	23

Schedule of Changes in Projected Benefit Obligations

The following table summarizes the Company’s change in benefit obligation for the periods ended September 30, 2021 and December 31, 2020:

Puget Energy and Puget Sound Energy	Qualified Pension Benefits				SERP Pension Benefits				Other Benefits
	Nine Months Ended		Year Ended		Nine Months Ended		Year Ended		Nine Months Ended		Year Ended
(Dollars in Thousands)	September 30, 2021		December 31, 2020		September 30, 2021		December 31, 2020		September 30, 2021		December 31, 2020
Change in benefit obligation:
Benefit obligation at beginning of period	$	849,383	$	774,305	$	46,742	$	63,000	$	12,114	$	11,627
Amendments	—		—		—		—		—		44
Service cost	20,166		24,337		344		756		117		190
Interest cost	16,786		25,180		879		1,464		226		368
Actuarial loss (gain)	4,580		69,413		(630)		3,663		(80)		604
Benefits paid	(37,807)		(42,775)		(1,485)		(22,141)		(669)		(906)
Medicare part D subsidy received	—		—		—		—		195		187
Administrative Expense	—		(1,077)		—		—		—		—
Benefit obligation at end of period	$	853,108	$	849,383	$	45,850	$	46,742	$	11,903	$	12,114