Taxation (Provision For Income Taxes) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Examination [Line Items]
Income (Loss) from Continuing Operations before Income Taxes, Domestic	$ 350	$ 440	$ 950
Income (Loss) from Continuing Operations before Income Taxes, Foreign	3,812	4,809	3,707
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	4,162	5,249	4,657
Current tax expense	928	908	652
Deferred tax expense	(299)	(113)	43
Provision for income taxes	629	795	695
Domestic Tax Authority [Member]
Income Tax Examination [Line Items]
Current tax expense	52	29	89
Deferred tax expense	2	11	3
Foreign Tax Authority [Member]
Income Tax Examination [Line Items]
Current tax expense	876	879	563
Deferred tax expense	$ (301)	$ (124)	$ 40