Debt - Cumulative Minimum Principal Amounts Committed to be Repaid (Details) - South Central Generating $ in Thousands	Sep. 30, 2019 USD ($)
For the year ending Dec. 31,
2019	$ 66,700
2020	132,300
2021	200,000
2022	266,700
2023	332,300
2024	$ 400,000

Long-Term Debt, Maturities, Cumulative Repayments Of Principal, Year Five

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Long-Term Debt, Maturities, Cumulative Repayments Of Principal, Year Four

+ References

No definition available.

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Long-Term Debt, Maturities, Cumulative Repayments Of Principal, Year Three

+ References

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Long-Term Debt, Maturities, Cumulative Repayments Of Principal, Year Two

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
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-Publisher FASB
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-Section S99
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-Topic 210
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-Section S99
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-Subparagraph (SX 210.5-02(22))
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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the remainder of the fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 3
-Subparagraph (SX 210.12-04.(a))
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