RECENT INVESTMENT ACTIVITY 2 (DETAILS) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended		3 Months Ended	9 Months Ended		3 Months Ended		9 Months Ended
	Sep. 30, 2011		Sep. 30, 2011		Sep. 30, 2012 Willmut Gas [Member]	Sep. 30, 2012 Willmut Gas [Member]	May 20, 2012 Willmut Gas [Member]	Sep. 30, 2012 South America Acquisition [Member]	Sep. 30, 2011 South America Acquisition [Member]	Sep. 30, 2012 South America Acquisition [Member]	Sep. 30, 2011 South America Acquisition [Member]	Sep. 13, 2011 Luz Del Sur [Member]	Apr. 06, 2011 Luz Del Sur [Member]	Apr. 06, 2011 Chilquinta Energia [Member]
Property, plant and equipment
Property, plant and equipment							$ 17
Total liabilities							(10)
Goodwill							10
Remeasurement of equity method investments			277	[1]
Revenue of acquiree since acquisition date					3	5		356	345	1,100	706
Net Income of acquiree since acquisition date								56	60	155	108
Earnings of acquiree since acquisition date								49	52	135	92
Pro forma revenues	2,576		7,775
Pro forma earnings	$ 289	[1]	$ 794	[1],[2]
Ownership Percentage Before Acquisition													38.00%	50.00%
Acquired percentage interest in joint venture							100.00%							100.00%
Ownership percentage after Luz Del Sur tender offer												80.00%

[1] As adjusted for the retrospective effect of a change in accounting principle as we discuss in Note 1.

[2] Excludes the $277 million gain related to remeasurement of equity method investments.