Financial Instruments And Risk Management (Effect Of Derivative Instruments On Statements Of Operations) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012		Mar. 31, 2011
Financial Instruments And Risk Management [Abstract]
Amount of Gain (Loss) Recognized in OCI on Derivative	$ 48	[1]	$ 475	[1]
Amount of Gain (Loss) Reclassified from Accumulated OCI into Income			98	[1]
Amount of Gain (Loss) Recognized in Income on Derivative			$ 3	[2]
Location of Gain (Loss) Reclassified from Accumulated OCI into Income	$26	[1]
Location Of Gain (Loss) Recognized in Income on Derivative	$3	[2]

[1] Effective portion of gain (loss)

[2] Ineffective portion of gain (loss)