Fair Value Of Financial Instruments (Schedule Of Fair Value Of Outstanding Derivative Positions) (Details) (USD $) In Millions	Sep. 30, 2011		Dec. 31, 2010
Derivatives, Fair Value [Line Items]
Asset	$ 1,735		$ 4,460
Liability	1,735		4,460
Commodity Forwards And Options [Member]
Derivatives, Fair Value [Line Items]
Asset	556	[1],[2]	3,437	[1],[2]
Liability	556	[1],[2]	3,437	[1],[2]
Fixed-Income Options And Futures [Member]
Derivatives, Fair Value [Line Items]
Asset	667	[2],[3]	578	[2],[3]
Liability	667	[2],[3]	578	[2],[3]
Stock Options And Futures [Member]
Derivatives, Fair Value [Line Items]
Asset	314	[2],[3]	237	[2],[3]
Liability	314	[2],[3]	237	[2],[3]
Index Options And Futures [Member]
Derivatives, Fair Value [Line Items]
Asset	198	[2],[3]	208	[2],[3]
Liability	$ 198	[2],[3]	$ 208	[2],[3]

[1] We determine the fair value of our forward contracts using standard valuation models that are based on market-based observable inputs including LIBOR rates and the spot price of the underlying instrument.

[2] We determine the fair value of our option contracts using standard valuation models that are based on market-based observable inputs including implied volatility, interest rates and the spot price of the underlying instrument.

[3] We determine the fair value of our futures contracts based upon quoted market prices and average quoted market yields.