Discontinued Operations And Held-For-Sale Businesses (Details) (USD $)	3 Months Ended		9 Months Ended						7 Months Ended	0 Months Ended		0 Months Ended		1 Months Ended	3 Months Ended		1 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013		Sep. 30, 2013 Sonel [Member]	Sep. 30, 2013 Kribi [Member]	Sep. 30, 2013 Dibamba [Member]	Mar. 31, 2014 Cameroon [Member]	Feb. 24, 2014 Saurashtra [Member]	Oct. 30, 2013 Saurashtra [Member] MW	Jan. 30, 2014 US Wind Projects [Member]	Nov. 30, 2013 US Wind Projects [Member] MW project	Jun. 30, 2014 Cameroon [Member]	Jun. 30, 2014 Cameroon [Member]	Sep. 30, 2014 Cameroon [Member] business	Nov. 30, 2013 Armenia Mountain [Member] MW	Sep. 30, 2014 Noncurrent Asset [Member] Cameroon [Member]	Jun. 30, 2014 Noncurrent Asset [Member] Cameroon [Member]
Discontinued Operations Income Loss
Revenue	$ 0	$ 130,000,000	$ 233,000,000	$ 556,000,000	[1]
Income (loss) from operations of discontinued businesses, before income tax	0	(41,000,000)	49,000,000	(35,000,000)	[1]
Income tax benefit (expense)	0	3,000,000	(22,000,000)	(2,000,000)	[1]
Income (loss) from operations of discontinued businesses, after income tax	0	(38,000,000)	27,000,000	(37,000,000)	[1]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Sale of ownership in subsidiary percent						56.00%	56.00%	56.00%					100.00%
Number of Equity Interests Sold																3
Disposal Group, Including Discontinued Operation, Consideration														202,000,000	202,000,000
Disposal Group, Including Discontinued Operation, Non-contingent Consideration, Fair Value, Amount to be Received																			40,000,000
Letter of Credit Related to Sale Agreement																40,000,000
Net proceeds received from sale of businesses										8,000,000		27,000,000		162,000,000
Impairment expenses			304,000,000	309,000,000					101,000,000
Carrying amount									435,000,000									40,000,000
Fair value less costs to sell									334,000,000
Net loss from disposal and impairments of discontinued businesses, after income tax	0	(78,000,000)	(56,000,000)	(111,000,000)	[1]										(7,000,000)
Generation capacity mega watts											39		234				101
Number of wind projects													3
Buyer option to purchase ownership percent																	100.00%
Buyer option to purchase ownership interest, sales price																	75,000,000
Deferred proceeds from divestiture of businesses												$ 3,000,000

[1] Includes the results of operations of our Ukraine utility businesses, which were sold in April 2013.