Acquisitions, Discontinued Operations and Dispositions - Summary of Results (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income/(loss) from discontinued operations, net of tax	$ 0	$ 0	$ 321
Discontinued Operations | South Central Portfolio
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Operating revenue			31
Operating costs and expenses			(23)
(Loss)/gain from operations of discontinued components, before tax			8
Income/(loss) on disposal of discontinued operations, net of tax			20
Income/(loss) from discontinued operations, net of tax			28
Discontinued Operations | Carlsbad Energy Holdings LLC
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Operating revenue			19
Operating costs and expenses			(9)
Other expenses			(5)
Gain/(loss) from discontinued operations, net of tax			5
Gain/(loss) on disposal of discontinued operations, net of tax			265
Income/(expense) from California property tax indemnification			22
Income/(expense) from other commitments, indemnification and fees			4
Income/(loss) on disposal of discontinued operations, net of tax			291
Income/(loss) from discontinued operations, net of tax			$ 296