Exit Activities and Discontinued Operations - Income from Discontinued Operations (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Oct. 31, 2021	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on sale		$ 5	$ 657
Income tax expense		1	170	$ 18
Income from discontinued operations, net of tax		4	602	58
Discontinued Operations, Held-for-sale | EnerBank
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Operating revenue		0	209	262
Operating expenses		0	60	130
Interest expense		0	34	56
Income before income taxes		0	115	76
Gain on sale	$ 657	5	657	0
Income from discontinued operations before income taxes		5	772	76
Income tax expense		1	170	18
Income from discontinued operations, net of tax		$ 4	$ 602	$ 58