Exit Activities and Discontinued Operations (Income from Discontinued Operations) (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Oct. 31, 2021	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on sale		$ 0	$ 5	$ 657
Income tax expense		0	1	170
Income from discontinued operations, net of tax		$ 1	4	602
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
Operating expenses			0	60
Interest expense			0	34
Income before income taxes			0	115
Gain on sale	$ 657		5	657
Income from discontinued operations before income taxes			5	772
Income tax expense			1	170
Income from discontinued operations, net of tax			$ 4	$ 602