Fair Value Measurements, Including Derivatives (Schedule of Quantitative Information About Level 3 Fair Value Measurements) (Details) - USD ($)		Jun. 30, 2025	Dec. 31, 2024
Fair Value, Inputs, Level 3 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets, fair value		$ 270,000,000
Total liability, fair value		5,000,000
Electricity [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets, fair value		202,000,000
Total liability, fair value		5,000,000
Natural gas [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total assets, fair value	[1]	68,000,000
Assets [Member] | Electricity [Member] | Fair Value, Inputs, Level 3 [Member] | Minimum [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value inputs market price (per MWh)	[2]	28
Assets [Member] | Electricity [Member] | Fair Value, Inputs, Level 3 [Member] | Maximum [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value inputs market price (per MWh)	[2]	86
Assets [Member] | Electricity [Member] | Fair Value, Inputs, Level 3 [Member] | Weighted average [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value inputs market price (per MWh)	[3]	49
Assets [Member] | Natural gas [Member] | Fair Value, Inputs, Level 3 [Member] | Minimum [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value inputs market price per decatherm	[2]	$ 1
Fair value inputs price volatility	[4]	11.00%
Assets [Member] | Natural gas [Member] | Fair Value, Inputs, Level 3 [Member] | Maximum [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value inputs market price per decatherm	[2]	$ 9
Fair value inputs price volatility	[4]	72.00%
Assets [Member] | Natural gas [Member] | Fair Value, Inputs, Level 3 [Member] | Weighted average [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value inputs market price per decatherm	[3]	$ 4
Fair value inputs price volatility	[3]	43.00%
Liability [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total liability, fair value	[5]	$ 4,000,000	$ 1,000,000
Liability [Member] | Electricity [Member] | Fair Value, Inputs, Level 3 [Member] | Minimum [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value inputs market price (per MWh)	[2]	28
Liability [Member] | Electricity [Member] | Fair Value, Inputs, Level 3 [Member] | Maximum [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value inputs market price (per MWh)	[2]	80
Liability [Member] | Electricity [Member] | Fair Value, Inputs, Level 3 [Member] | Weighted average [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value inputs market price (per MWh)	[3]	$ 51

[1] Includes basis.

[2] Represents market prices beyond defined terms for Levels 1 and 2.

[3] Averages weighted by volume.

[4] Represents volatilities unrepresented in published markets.

[5] Excludes derivative liabilities of $4 million at June 30, 2025, which are not subject to master netting or similar arrangements. DESC did not have any derivative liabilities at December 31, 2024 which were not subject to master netting or similar arrangements.