Segment Reporting (Other Expenses By Segment) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Depreciation expense	$ 898	$ 907	$ 787
Capital expenditures	852	1,436	1,548
Operating Segments [Member]
Segment Reporting Information [Line Items]
Depreciation expense	887	896	775
Capital expenditures	852	1,432	1,540
Operating Segments [Member] | European Union [Member]
Segment Reporting Information [Line Items]
Depreciation expense	254	269	213
Capital expenditures	466	813	956
Operating Segments [Member] | Eastern Europe [Member]
Segment Reporting Information [Line Items]
Depreciation expense	147	101	76
Capital expenditures	132	136	97
Operating Segments [Member] | Middle East And Africa [Member]
Segment Reporting Information [Line Items]
Depreciation expense	90	105	88
Capital expenditures	35	65	85
Operating Segments [Member] | South & Southeast Asia [Member]
Segment Reporting Information [Line Items]
Depreciation expense	142	154	153
Capital expenditures	100	129	140
Operating Segments [Member] | East Asia And Australia [Member]
Segment Reporting Information [Line Items]
Depreciation expense	185	173	160
Capital expenditures	67	215	87
Operating Segments [Member] | Latin America & Canada [Member]
Segment Reporting Information [Line Items]
Depreciation expense	69	94	85
Capital expenditures	52	74	175
Other [Member]
Segment Reporting Information [Line Items]
Depreciation expense	11	11	12
Capital expenditures	$ 0	$ 4	$ 8