Quarterly Financial Data (Schedule Of Quarterly Financial Data) (Details) - USD ($) $ / shares in Units, $ 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
Quarterly Financial Information Disclosure [Abstract]
Revenues	$ 17,911	$ 19,980	$ 15,751	$ 22,917	$ 28,341	$ 25,146	$ 24,258	$ 23,382	$ 76,559	$ 101,127	$ 94,005
Cost of Revenue	18,708	16,930	17,810	18,645	22,090	21,040	19,536	18,824	72,093	81,490	76,612
Earnings from operations	(2,204)	1,259	(3,380)	2,350	4,175	2,227	2,710	2,875	(1,975)	11,987	10,344
Net (loss)/earnings	$ (1,010)	$ 1,167	$ (2,942)	$ 2,149	$ 3,424	$ 2,363	$ 2,196	$ 2,477	$ (636)	$ 10,460	$ 8,458
Basic (loss)/earnings per share	$ (1.79)	$ 2.07	$ (5.21)	$ 3.79	$ 6.00	$ 4.11	$ 3.77	$ 4.19	$ (1.12)	$ 18.05	$ 14.03
Diluted earnings per share	$ (1.79)	$ 2.05	$ (5.21)	$ 3.75	$ 5.93	$ 4.07	$ 3.73	$ 4.15	$ (1.12)	$ 17.85	$ 13.85