Commitments and Contingencies - Purchase Obligations (Details) $ in Millions	12 Months Ended
Dec. 31, 2022 USD ($)	Jan. 31, 2022 MW
Posey Solar
Purchase Obligations
Solar array generating capacity (in Megawatts) \| MW		191
Natural Gas and Coal Supply
Purchase Obligations
2023	$ 1,014
2024	887
2025	648
2026	488
2027	421
2028 and beyond	2,070
Natural Gas and Coal Supply \| CERC Corp
Purchase Obligations
2023	894
2024	827
2025	599
2026	445
2027	377
2028 and beyond	1,954
Technology Hardware and Software
Purchase Obligations
2023	151
2024	208
2025	681
2026	45
2027	86
2028 and beyond	$ 453
Technology Hardware and Software \| Minimum \| Capital Addition Purchase Commitments
Purchase Obligations
Purchase obligation term	15 years
Technology Hardware and Software \| Maximum \| Capital Addition Purchase Commitments
Purchase Obligations
Purchase obligation term	25 years

Solar Array Generating Capacity

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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Amount of purchase arrangement to be paid after fifth fiscal year following current fiscal year. Includes, but is not limited to, recorded and unrecorded purchase obligations, long-term purchase commitment, and short-term purchase commitment. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

No definition available.

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Amount of purchase arrangement to be paid in fifth fiscal year following current fiscal year. Includes, but is not limited to, recorded and unrecorded purchase obligations, long-term purchase commitment, and short-term purchase commitment. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

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Amount of purchase arrangement to be paid in fourth fiscal year following current fiscal year. Includes, but is not limited to, recorded and unrecorded purchase obligations, long-term purchase commitment, and short-term purchase commitment. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

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Amount of purchase arrangement to be paid in next fiscal year following current fiscal year. Includes, but is not limited to, recorded and unrecorded purchase obligations, long-term purchase commitment, and short-term purchase commitment. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

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- Definition

Amount of purchase arrangement to be paid in second fiscal year following current fiscal year. Includes, but is not limited to, recorded and unrecorded purchase obligations, long-term purchase commitment, and short-term purchase commitment. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

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- Definition

Amount of purchase arrangement to be paid in third fiscal year following current fiscal year. Includes, but is not limited to, recorded and unrecorded purchase obligations, long-term purchase commitment, and short-term purchase commitment. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

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- Definition

Term of the unrecognized unconditional purchase obligation, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 440
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=123406679&loc=d3e25336-109308

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