Exit Activities and Discontinued Operations - Income from Discontinued Operations (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended		9 Months Ended
	Oct. 31, 2021	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on sale				$ 5	$ 0
Income tax expense		$ 0	$ 9	1	25
Income from discontinued operations, net of tax		0	30	4	82
Discontinued Operations, Held-for-sale | EnerBank
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Operating revenue		0	70	0	209
Operating expenses		0	17	0	60
Interest expense		0	11	0	34
Income before income taxes		0	42	0	115
Gain on sale	$ 657	0	(3)	5	(8)
Income from discontinued operations before income taxes		0	39	5	107
Income tax expense		0	9	1	25
Income from discontinued operations, net of tax		$ 0	$ 30	$ 4	$ 82