Fair Value Measurements, Including Derivatives (Tables)

3 Months Ended

Mar. 31, 2024

Fair Value Disclosures [Abstract]

Schedule of Quantitative Information About Level 3 Fair Value Measurements

The following table presents DESC’s quantitative information about Level 3 fair value measurements at March 31, 2024. The range and weighted average are presented in dollars for market price inputs and percentages for price volatility.

	Fair Value (millions)		Valuation Techniques	Unobservable Input		Range	Weighted Average(1)
Assets
Physical forwards:
Electricity	$	246	Discounted cash flow	Market price (per MWh)	(3)	24-102	51
Physical options:
Natural gas(2)	$	7	Option model	Market price (per Dth)	(3)	1-3	2
				Price volatility	(4)	10%-51%	34%
Total assets	$	253

(1)Averages weighted by volume.

(2)Includes basis.

(3)Represents market prices beyond defined terms for Levels 1 and 2.

(4)Represents volatilities unrepresented in published markets.

Schedule of Sensitivity of The Fair Value Measurements To Changes in The Significant Unobservable Inputs

Sensitivity of the fair value measurements to changes in the significant unobservable inputs is as follows:

Significant Unobservable Inputs	Position	Change to Input	Impact on Fair Value Measurement
Market price	Buy	Increase (decrease)	Gain (loss)
Market price	Sell	Increase (decrease)	Loss (gain)
Price volatility	Buy	Increase (decrease)	Gain (loss)
Price volatility	Sell	Increase (decrease)	Loss (gain)

Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis

The following table presents DESC’s assets and liabilities that are measured at fair value on a recurring basis for each hierarchy level, including both current and noncurrent portions:

(millions)	Level 1		Level 2		Level 3		Total
At March 31, 2024
Assets
Commodity	$	—	$	1	$	253	$	254
Interest rate		—		1		—		1
Total assets	$	—	$	2	$	253	$	255
Liabilities
Interest rate	$	—	$	2	$	—	$	2
Total liabilities	$	—	$	2	$	—	$	2
At December 31, 2023
Assets
Commodity	$	—	$	—	$	176	$	176
Interest rate		—		—		—		—
Total assets	$	—	$	—	$	176	$	176
Liabilities
Interest rate	$	—	$	4	$	—	$	4
Total liabilities	$	—	$	4	$	—	$	4

Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis and included in Level 3

The following table presents the net change in DESC’s assets and liabilities measured at fair value on a recurring basis and included in the Level 3 fair value category.

	Three Months Ended March 31,
	2024			2023
(millions)
Beginning balance	$	176		$	251
Total realized and unrealized gains (losses):
Included in earnings:
Purchased power		(2	)		1
Included in regulatory assets/liabilities		70			(63	)
Settlements		2			(1	)
Purchases		7			—
Ending balance	$	253		$	188

Schedule of Carrying Values and Estimated Fair Values of Debt Instruments

For financial instruments that are not recorded at fair value, the carrying amounts and estimated fair values are as follows:

	March 31, 2024				December 31, 2023
(millions)	Carrying Amount		Estimated Fair Value(1)		Carrying Amount		Estimated Fair Value(1)
Long-term debt(2)	$	4,219	$	4,221	$	4,219	$	4,301
Affiliated long-term debt(3)		230		230		230		230

(1)Fair value is estimated using market prices, where available, and interest rates currently available for issuance of debt with similar terms and remaining maturities. All fair value measurements are classified as Level 2. The carrying amount of debt issuances with short-term maturities and variable rates refinanced at current market rates is a reasonable estimate of their fair value.

(2)Carrying amount includes current portions, if any, presented in securities due within one year and amounts which represent the unamortized debt issuance costs and discount or premium.

(3)Carrying amount includes current portions presented in affiliated and related party payables.