RECENT INVESTMENT ACTIVITY (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended			0 Months Ended		3 Months Ended	6 Months Ended	3 Months Ended	6 Months Ended				3 Months Ended	6 Months Ended					1 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010		Apr. 06, 2011 South America Acquisition [Member]		Jun. 30, 2011 South America Acquisition [Member]	Jun. 30, 2011 South America Acquisition [Member]	Jun. 30, 2011 Luz Del Sur [Member]	Jun. 30, 2011 Luz Del Sur [Member]	Sep. 06, 2011 Luz Del Sur [Member]	Apr. 06, 2011 Luz Del Sur [Member]		Jun. 30, 2011 Chilquinta Energia [Member]	Jun. 30, 2011 Chilquinta Energia [Member]	Apr. 06, 2011 Chilquinta Energia [Member]		Apr. 06, 2011 Other Holding Companies [Member]		Apr. 30, 2010 Mexican Pipeline And Natural Gas Infrastructure Member
Business Acquisition Line Items
Ownership Percentage Before Acquisition													38.00%				50.00%
Acquired percentage interest in joint venture													76.00%				100.00%
Maximum percent of Luz del Sur minority interests												14.73%
Luz del Sur tender offer, maximum cash expenditure												$ 164
Consideration withheld related to purchase						32
Fair value of businesses acquired [Abstract]
Cash consideration (fair value of total consideration)						888							385				495		8
Fair value of equity method investments immediately prior to the acquisition						882							385				495		2
Fair value of noncontrolling interests						279							242				37
Total fair value of businesses acquired						2,049							1,012				1,027		10
Property, plant and equipment
Cash						245							22				219		4
Accounts receivable						266	[1]						101	[1]			159	[1]	6	[1]
Other current assets						39							19				20
Property, plant and equipment						1,485							931				554
Other noncurrent assets						66											66
Accounts payable						(138)							(59)				(79)
Short-term and current portion of long-term debt						(47)							(47)
Other current liabilities						(85)							(56)				(29)
Long-term debt						(473)							(179)				(294)
Other noncurrent liabilities						(268)							(178)				(90)
Total identifiable net assets						1,090							554				526		10
Goodwill						959							458				501
Acquisition-related costs (included in Other Operation and Maintenance expense in the Condensed Consolidated Statements of Operations for the three months and six months ended June 30, 2011)								2	2	1	1				1	1
Allowance for doubtful accounts													1				6
Remeasurement of equity method investments	277		277						277
Book value of equity interests						605
Revenue of acquiree since acquisition date									361
Net Income of acquiree since acquisition date									48
Earnings of acquiree since acquisition date									40
Pro forma revenues	2,422	2,353	5,199	5,163
Pro forma earnings	234	245	517	647	[2]
Cash consideration (fair value of total consideration)																					307
Business acquisition, Cash paid, net of cash acquired						611															292
Contributions to equity method investees		$ 65

[1] We expect acquired accounts receivable to be substantially realizable in cash. Accounts receivable are net of collection allowances of $6 million for Chile and $1 million for Peru.

[2] Pro forma earnings in the six months ended June 30, 2010 include a $277 million gain on this transaction related to the remeasurement of equity method investments.