Discontinued Operations and Held-For-Sale Businesses (Schedule of Disposal Groups, Including Discontinued Operations) (Details) - USD ($) $ in Millions	3 Months Ended			12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019	Jun. 30, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income tax expense				$ 0	$ 0	$ 2
Income (loss) from operations of discontinued businesses, after income tax				0	0	(9)
Net loss from disposal and impairments of discontinued businesses, after income tax				3	1	225
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent				3	1	218
Asset Impairment Charges				1,066	277	355
Other Asset Impairment Charges	$ 849	$ 69	$ 116	$ 864	$ 185	$ 208
Eletropaulo Subsidiary [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net loss from disposal and impairments of discontinued businesses, after income tax			$ 199