Exit Activities and Discontinued Operations - Narrative (Details) - USD ($) $ in Millions		1 Months Ended	12 Months Ended			27 Months Ended
	Oct. 01, 2021	Oct. 31, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2021
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	$ 657	$ 0	$ 0
Post-closing purchase price adjustment			36			$ 36
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			0	13		16
Costs incurred and capitalized			1	$ 2
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]
Regulatory asset			$ 7			7
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