Benefit Plans and Other Postretirement Benefits (Tables)

12 Months Ended

Dec. 31, 2019

Benefit Plans and Other Postretirement Benefits [Abstract]

Target Asset Allocations and Plan Assets Measured at Fair Value

or each of the fair value hierarchy levels, SPS’ pension plan assets measured at fair value:

	Dec. 31, 2019 (a)													Dec. 31, 2018 (a)
(Millions of Dollars)	Level 1			Level 2		Level 3		Measured at NAV			Total			Level 1		Level 2		Level 3		Measured at NAV			Total
Cash equivalents	$	18.9		$	—	$	—	$	—		$	18.9		$	21.6	$	—	$	—	$	—		$	21.6
Commingled funds	202.5			—		—		144.8			347.3			128.6		—		—		132.5			261.1
Debt securities	—			98.2		0.6		—			98.8			—		98.1		—		—			98.1
Equity securities	12.1			—		—		—			12.1			14.4		—		—		—			14.4
Other	(16.8		)	0.7		—		(2.8		)	(18.9		)	0.2		0.8		—		(4.0		)	(3.0		)
Total	$	216.7		$	98.9	$	0.6	$	142.0		$	458.2		$	164.8	$	98.9	$	—	$	128.5		$	392.2

^(a)  See Note 8 for further information on fair value measurement inputs and methods.

For each of the fair value hierarchy levels, SPS’ proportionate allocation of the total postretirement benefit plan assets that were measured at fair value:

	Dec. 31, 2019 (a)										Dec. 31, 2018 (a)
(Millions of Dollars)	Level 1		Level 2		Level 3		Measured at NAV		Total		Level 1		Level 2		Level 3		Measured at NAV		Total
Cash equivalents	$	2.2	$	—	$	—	$	—	$	2.2	$	1.8	$	—	$	—	$	—	$	1.8
Insurance contracts	—		4.9		—		—		4.9		—		4.3		—		—		4.3
Commingled funds:	6.7		—		—		7.4		14.1		12.8		—		—		3.8		16.6
Debt securities:	—		22.1		0.1		—		22.2		—		17.2		—		—		17.2
Equity securities:	—		—		—		—		—		—		—		—		—		—
Other	—		0.2		—		—		0.2		—		0.1		—		—		0.1
Total	$	8.9	$	27.2	$	0.1	$	7.4	$	43.6	$	14.6	$	21.6	$	—	$	3.8	$	40.0

^(a) 

See Note 8 for further information on fair value measurement inputs and methods.

Target asset allocations:

	Pension Benefits				Postretirement Benefits
	2019		2018		2019		2018
Domestic and international equity securities	37	%	35	%	15	%	18	%
Long-duration fixed income securities	30		32		—		—
Short-to-intermediate fixed income securities	14		16		72		70
Alternative investments	17		15		9		8
Cash	2		2		4		4
Total	100	%	100	%	100	%	100	%

Funded Status of Plans

Funded Status — Comparisons of the actuarially computed benefit obligation, changes in plan assets and funded status of the pension and postretirement health care plans for Xcel Energy are presented in the following table:

	Pension Benefits						Postretirement Benefits
(Millions of Dollars)	2019			2018			2019			2018
Change in Benefit Obligation:
Obligation at Jan. 1	$	477.8		$	515.9		$	41.8		$	47.0
Service cost	8.8			9.7			0.9			1.1
Interest cost	20.1			18.4			1.7			1.6
Plan amendments	—			—			—			—
Actuarial loss (gain)	44.2			(34.8		)	0.4			(5.1		)
Plan participants’ contributions	—			—			0.6			0.6
Benefit payments (a)	(32.1		)	(31.4		)	(2.2		)	(3.4		)
Obligation at Dec. 31	$	518.8		$	477.8		$	43.2		$	41.8
Change in Fair Value of Plan Assets:
Fair value of plan assets at Jan. 1	$	392.2		$	433.2		$	40.0		$	44.1
Actual return on plan assets	80.2			(17.6		)	5.1			(1.3		)
Employer contributions	17.9			8.0			0.1			—
Plan participants’ contributions	—			—			0.6			0.6
Benefit payments	(32.1		)	(31.4		)	(2.2		)	(3.4		)
Fair value of plan assets at Dec. 31	$	458.2		$	392.2		$	43.6		$	40.0
Funded status of plans at Dec. 31	$	(60.6	)	$	(85.6	)	$	0.4		$	(1.8	)
Amounts recognized in the Balance Sheet at Dec. 31:
Noncurrent assets	—			—			0.4			—
Noncurrent liabilities	(60.6		)	(85.6		)	—			(1.8		)
Net amounts recognized	$	(60.6	)	$	(85.6	)	$	0.4		$	(1.8	)
Significant Assumptions Used to Measure Benefit Obligations:
Discount rate for year-end valuation	3.49		%	4.31		%	3.47		%	4.32		%
Expected average long-term increase in compensation level	3.75			3.75			N/A			N/A
Mortality table	Pri-2012			RP-2014			Pri-2012			RP-2014
Health care costs trend rate — initial: Pre-65	N/A			N/A			6.00		%	6.50		%
Health care costs trend rate — initial: Post-65	N/A			N/A			5.10		%	5.30		%
Ultimate trend assumption — initial: Pre-65	N/A			N/A			4.50		%	4.50		%
Ultimate trend assumption — initial: Post-65	N/A			N/A			4.50		%	4.50		%
Years until ultimate trend is reached	N/A			N/A			3			4

^(a)  Includes approximately $6.8 million in 2019 and $6.9 million in 2018, of lump-sum benefit payments used in the determination of a settlement charge.

Accumulated benefit obligation for the pension plan was $481.1 million and $445.8 million as of Dec. 31, 2019 and 2018, respectively.

Components of Net Periodic Benefit Costs

Components of net periodic benefit cost (credit) and the amounts recognized in other comprehensive income and regulatory assets and liabilities are as follows:

	Pension Benefits									Postretirement Benefits
(Millions of Dollars)	2019			2018			2017			2019			2018			2017
Service cost	$	8.8		$	9.7		$	9.8		$	0.9		$	1.1		$	0.9
Interest cost	20.1			18.4			19.7			1.7			1.6			1.7
Expected return on plan assets	(28.6		)	(28.3		)	(27.9		)	(2.0		)	(2.5		)	(2.4		)
Amortization of prior service credit	(0.1		)	(0.1		)	—			(0.5		)	(0.4		)	(0.4		)
Amortization of net loss	11.3			14.1			13.0			(0.4		)	(0.4		)	(0.6		)
Settlement charge (a)	2.4			3.2			—			—			—			—
Net periodic pension cost (credit)	13.9			17.0			14.6			(0.3		)	(0.6		)	(0.8		)
Costs not recognized due to effects of regulation	0.9			(2.2		)	0.3			—			—			—
Net benefit cost (credit) recognized for financial reporting	$	14.8		$	14.8		$	14.9		$	(0.3	)	$	(0.6	)	$	(0.8	)
Significant Assumptions Used to Measure Costs:
Discount rate	4.31		%	3.63		%	4.13		%	4.32		%	3.62		%	4.13		%
Expected average long-term increase in compensation level	3.75			3.75			3.75			—			—			—
Expected average long-term rate of return on assets	6.78			6.78			6.78			5.30			5.80			5.80

^(a) 

A settlement charge is required when the amount of all lump-sum distributions during the year is greater than the sum of the service and interest cost components of the annual net periodic pension cost. In 2019 and 2018, as a result of lump-sum distributions during the 2019 and 2018 plan years, SPS recorded a total pension settlement charge of $2.4 million and $3.2 million in 2019 and 2018, respectively. A total of $0.6 million and $0.7 million of that amount was recorded in the income statement in 2019 and 2018, respectively.

Projected Benefit Payments for the Pension and Postretirement Benefit Plans

Projected Benefit Payments

SPS’ projected benefit payments:

(Millions of Dollars)	Projected Pension Benefit Payments		Gross Projected Postretirement Health Care Benefit Payments		Expected Medicare Part D Subsidies		Net Projected Postretirement Health Care Benefit Payments
2020	$	30.7	$	2.9	$	—	$	2.9
2021	29.4		2.9		—		2.9
2022	30.3		2.9		—		2.9
2023	30.4		2.9		—		2.9
2024	30.4		2.8		—		2.8
2025-2029	153.5		13.2		0.1		13.1

Other Postretirement Benefits Plan [Member]

Benefit Plans and Other Postretirement Benefits [Abstract]

Amounts Not Yet Recognized as Components of Net Periodic Benefit Cost

	Pension Benefits						Postretirement Benefits
(Millions of Dollars)	2019			2018			2019			2018
Amounts Not Yet Recognized as Components of Net Periodic Benefit Cost:
Net loss	$	209.7		$	230.9		$	(11.9	)	$	(9.6	)
Prior service credit	(1.1		)	(1.2		)	(1.4		)	(1.8		)
Total	$	208.6		$	229.7		$	(13.3	)	$	(11.4	)
Amounts Not Yet Recognized as Components of Net Periodic Benefit Cost Have Been Recorded as Follows Based Upon Expected Recovery in Rates:
Current regulatory assets	$	11.0		$	12.9		$	—		$	—
Noncurrent regulatory assets	197.6			216.8			—			—
Current regulatory liabilities	—			—			(0.8		)	(0.9		)
Noncurrent regulatory liabilities	—			—			(12.5		)	(10.5		)
Total	$	208.6		$	229.7		$	(13.3	)	$	(11.4	)

Measurement date Dec. 31, 2019 Dec. 31, 2018 Dec. 31, 2019 Dec. 31, 2018