Exit Activities and Discontinued Operations - Narrative (Details) - USD ($) $ in Millions		1 Months Ended		12 Months Ended			39 Months Ended
	Oct. 01, 2021	Mar. 31, 2022	Oct. 31, 2021	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2022
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain from divestiture of business				$ 5	$ 657
Discontinued Operations, Held-for-sale | EnerBank
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from divestiture of businesses	$ 1,000
Gain from divestiture of business			$ 657	5	657	$ 0
Gain from divestiture of business related to post-closing adjustment		$ 6
Post-closing purchase price adjustment					36
Retention Benefits
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cost deferred				24	7
Retention Benefits | D.E. Karn Generating Complex
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Expected cost				35			$ 35
Retention and severance costs							16
Costs incurred and capitalized				0	$ 1
Retention Benefits | D.E. Karn Generating Complex | Retention Incentive Program
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cost deferred							11
Retention Benefits | D.E. Karn Generating Complex | Property, Plant and Equipment
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Costs incurred and capitalized							4
Retention Benefits | J.H. Campbell Generating Units
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Expected cost				50			$ 50
Retention Benefits | J.H. Campbell Generating Units | Retention Incentive Program
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cost deferred				20
Severance Benefits | J.H. Campbell Generating Units
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Retention and severance costs				$ 4