Fair Value Measurements, Including Derivatives (Tables)

3 Months Ended

Mar. 31, 2023

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, 2023. The range and weighted average are presented in dollars for market price inputs.

	Fair Value (millions)		Valuation Techniques	Unobservable Input		Range	Weighted Average(1)
Assets
Physical forwards:
Electricity	$	188	Discounted cash flow	Market price (per MWh)	(2)	18-106	48
Total assets	$	188

(1)Averages weighted by volume.

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

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)

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, 2023
Assets
Commodity	$	—	$	—	$	188	$	188
Total assets	$	—	$	—	$	188	$	188
Liabilities
Interest rate	$	—	$	4	$	—	$	4
Total liabilities	$	—	$	4	$	—	$	4
At December 31, 2022
Assets
Commodity	$	—	$	—	$	251	$	251
Interest rate		—		1		—		1
Total assets	$	—	$	1	$	251	$	252
Liabilities
Interest rate	$	—	$	2	$	—	$	2
Total liabilities	$	—	$	2	$	—	$	2

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,
	2023			2022
(millions)
Beginning balance	$	251		$	148
Total realized and unrealized gains:
Included in earnings:
Purchased power		1			3
Included in regulatory assets/liabilities		(63	)		77
Settlements		(1	)		(3	)
Transfers out of Level 3		—			—
Ending balance	$	188		$	225

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, 2023				December 31, 2022
(millions)	Carrying Amount		Estimated Fair Value(1)		Carrying Amount		Estimated Fair Value(1)
Long-term debt(2)	$	3,726	$	3,771	$	3,725	$	3,614
Affiliated long-term debt		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 included in securities due within one year and amounts which represent the unamortized debt issuance costs and discount or premium.