Fair Value (Instruments Not Measured at Fair Value) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014		Dec. 31, 2013
Carrying Amount [Member]
Financial Instruments Not Measured At Fair Value In the Condensed Consolidated Balance Sheets [Abstract]
Accounts receivable - noncurrent	$ 220	[1]	$ 260	[1]
Non-recourse debt	15,940		15,380
Recourse debt	5,783		5,669
Fair Value [Member]
Financial Instruments Not Measured At Fair Value In the Condensed Consolidated Balance Sheets [Abstract]
Accounts receivable - noncurrent	194	[1]	194	[1]
Non-recourse debt	16,500		15,620
Recourse debt	6,147		6,164
Value added tax	38		46
Fair Value [Member] | Level 1 [Member]
Financial Instruments Not Measured At Fair Value In the Condensed Consolidated Balance Sheets [Abstract]
Accounts receivable - noncurrent	0	[1]	0	[1]
Non-recourse debt	0		0
Recourse debt	0		0
Fair Value [Member] | Level 2 [Member]
Financial Instruments Not Measured At Fair Value In the Condensed Consolidated Balance Sheets [Abstract]
Accounts receivable - noncurrent	0	[1]	0	[1]
Non-recourse debt	14,143		13,397
Recourse debt	6,147		6,164
Fair Value [Member] | Level 3 [Member]
Financial Instruments Not Measured At Fair Value In the Condensed Consolidated Balance Sheets [Abstract]
Accounts receivable - noncurrent	194	[1]	194	[1]
Non-recourse debt	2,357		2,223
Recourse debt	$ 0		$ 0

[1] These accounts receivable principally relate to amounts due from CAMMESA, the administrator of the wholesale electricity market in Argentina, and are included in “Noncurrent assets — Other” in the accompanying condensed consolidated balance sheets. The fair value and carrying amount of these accounts receivable exclude value-added tax of $38 million and $46 million at June 30, 2014 and December 31, 2013, respectively.