Taxation (Provision For Income Taxes) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Examination [Line Items]
Income (Loss) from Continuing Operations before Income Taxes, Domestic	$ 950	$ 527	$ 766
Income (Loss) from Continuing Operations before Income Taxes, Foreign	3,707	3,195	4,184
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	4,657	3,722	4,950
Current tax expense	652	359	824
Deferred tax expense	43	(498)	(9)
Provision for income taxes	695	(139)	815
Domestic Tax Authority [Member]
Income Tax Examination [Line Items]
Current tax expense	89	46	97
Deferred tax expense	3	2	(27)
Foreign Tax Authority [Member]
Income Tax Examination [Line Items]
Current tax expense	563	313	727
Deferred tax expense	$ 40	$ (500)	$ 18