Basis Of Presentation (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Basis of Presentation [Line Items]
Change in diluted earnings per share due to net favorable/(unfavorable) cumulative catch-up adjustments	$ (0.11)	$ 0.21	$ (0.95)	$ (0.38)
Increase/(Decrease) in Earnings from operations due to change in accounting estimate	$ (69)	$ 210	$ (656)	$ (384)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Effect on Net earnings/(loss)	$ 2,279	$ 1,704	$ 3,264	$ 4,150
Effect on Earnings Per Share, Diluted	$ 3.60	$ 2.47	$ 5.04	$ 5.92
Effect on Net Cash Provided by Operating Activities			$ 7,667	$ 6,244
Effect on Net Cash used by Financing Activities			(8,013)	$ (7,609)
Adjustments for New Accounting Pronouncement [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Effect on Net earnings/(loss)	$ 10		$ 64
Effect on Earnings Per Share, Diluted	$ 0.02		$ 0.10
Effect on Net Cash Provided by Operating Activities			$ 64
Effect on Net Cash used by Financing Activities			$ (64)