Investments In and Advances To Affiliates (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended			9 Months Ended			0 Months Ended	9 Months Ended		0 Months Ended		0 Months Ended
	Sep. 30, 2014		Sep. 30, 2013	Sep. 30, 2014		Sep. 30, 2013	Apr. 11, 2014 Global Infrastructure Partners [Member]	Sep. 30, 2014 Minority Owned Affiliates [Member]	Sep. 30, 2013 Minority Owned Affiliates [Member]	Jul. 02, 2014 Silver Ridge Power [Member]	Jul. 02, 2014 Silver Ridge Power [Member]	Jul. 01, 2014 Silver Ridge - Italy [Member]	Sep. 30, 2014 Silver Ridge - Italy [Member]	Sep. 30, 2014 Silver Ridge- Puerto Rico [Member]	Sep. 30, 2014 Silver Ridge- Italy and Spain [Member]
Investments in and Advances to Affiliates [Line Items]
Equity Method Investment, Ownership Percentage											50.00%		50.00%	50.00%
Equity Method Investment, Purchase Price Agreement										$ 179		$ 42
Revenue								716	830
Operating margin	767		927	2,380		2,577		159	191
Net income	508		223	849		755		89	(9)
Acquisitions, net of cash acquired				(728)		(3)
Proceeds from Interests in Affiliate				1,668		167	730
Equity method Investment balance reclassed to Other noncurrent assets															32
accumulated other comprehensive income reclassed to other noncurrent assets	$ 40	[1]		$ 40	[1]										$ 40

[1] (1) Reclassification resulting from Silver Ridge Power transaction. See Note 7 — Investments In and Advances to Affiliates for further information.