Derivative Instruments and Hedging Activities (Details 1) (USD $) In Millions	Sep. 30, 2011	Dec. 31, 2010
Fair Values of Derivative Instruments Recorded in the Consolidated Balance Sheet
Derivative asset fair value net	$ 399	$ 306
Derivative liability fair value net	75	318
Prepaid Assets and Other [Member]
Fair Values of Derivative Instruments Recorded in the Consolidated Balance Sheet
Derivative asset fair value net	306	167
Deferred Charges and Other [Member]
Fair Values of Derivative Instruments Recorded in the Consolidated Balance Sheet
Derivative asset fair value net	93	139
Derivative Instruments [Member]
Fair Values of Derivative Instruments Recorded in the Consolidated Balance Sheet
Derivative liability fair value net	50	194
Other Liabilities [Member]
Fair Values of Derivative Instruments Recorded in the Consolidated Balance Sheet
Derivative liability fair value net	$ 25	$ 124