Segment 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, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	$ 23,286	$ 23,898	$ 24,755	$ 22,632	$ 23,573	$ 25,849	$ 24,543	$ 22,149	$ 94,571	$ 96,114	$ 90,762
Non-U.S. [member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues									55,806	56,827	52,920
Asia, Other Than China [member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues									10,553	13,433	11,900
Europe [member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues									13,790	12,248	11,898
China [member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues									10,312	12,556	11,029
Middle East [member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues									13,297	10,846	9,243
Oceania [member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues									1,843	2,601	1,757
Canada [member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues									2,076	1,870	1,901
Africa [member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues									1,999	1,398	2,596
Latin America, Caribbean And Other [member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues									1,936	1,875	2,596
United States [member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues									$ 38,765	$ 39,287	$ 37,842