Segment and Revenue Information (Schedule Of Revenue from External Customers Attributed to Foreign Countries by Geographic Area) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	$ 17,911	$ 19,980	$ 15,751	$ 22,917	$ 28,341	$ 25,146	$ 24,258	$ 23,382	$ 76,559	$ 101,127	$ 94,005
Non-U.S.
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									42,137	56,451	50,299
Asia, Other Than China
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									10,662	12,141	9,195
Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									10,366	12,976	11,240
China
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									5,684	13,764	11,932
Middle East
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									9,272	9,745	11,433
Oceania
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									2,006	2,298	1,931
Canada
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									2,019	2,583	2,212
Africa
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									1,113	1,486	815
Latin America, Caribbean And Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									1,015	1,458	1,541
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									$ 42,681	$ 44,676	$ 43,706