Derivative Financial Instruments (Schedule Of Derivative Financial Instruments Included In The Consolidated Comprehensive Statements Of Earnings) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Derivatives, Fair Value [Line Items]
Net gains (losses) recognized in consolidated comprehensive statements of earnings	$ (194)	$ 430
Commodity Derivatives [Member] | Oil, Gas And NGL Derivatives [Member]
Derivatives, Fair Value [Line Items]
Net gains (losses) recognized in consolidated comprehensive statements of earnings	33	294
Commodity Derivatives [Member] | Marketing And Midstream Revenues [Member]
Derivatives, Fair Value [Line Items]
Net gains (losses) recognized in consolidated comprehensive statements of earnings		2
Interest Rate Derivatives [Member] | Other Nonoperating Items [Member]
Derivatives, Fair Value [Line Items]
Net gains (losses) recognized in consolidated comprehensive statements of earnings	(72)	1
Foreign Currency Derivatives [Member] | Other Nonoperating Items [Member]
Derivatives, Fair Value [Line Items]
Net gains (losses) recognized in consolidated comprehensive statements of earnings	$ (155)	$ 133