Risks And Uncertainties (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2010 years integer	Dec. 31, 2009	Dec. 31, 2008	Dec. 31, 2007
Risks And Uncertainties Details Abstract
Cash and cash equivalents	$ 2,552	$ 1,780	$ 864	$ 2,014
Percent Of Revenue Generated Outside US	86.00%
Range Of Remaining Terms Of Power Sales Contracts	The remaining term of the power sales contracts related to the Company’s power plants range from less than one to 38 years.
Number Of Countries In Which Entity Operates	28
Percent Of Revenue From Discontinued Operations Generated Outside US	56.00%

- Definition

Includes currency on hand as well as demand deposits with banks or financial institutions. It also includes other kinds of accounts that have the general characteristics of demand deposits in that the Entity may deposit additional funds at any time and also effectively may withdraw funds at any time without prior notice or penalty. Cash equivalents, excluding items classified as marketable securities, include short-term, highly liquid investments that are both readily convertible to known amounts of cash, and so near their maturity that they present minimal risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three years ago does not become a cash equivalent when its remaining maturity is three months. Compensating balance arrangements that do not legally restrict the withdrawal or usage of cash amounts may be reported as Cash and Cash Equivalents, while legally restricted deposits held as compensating balances against borrowing arrangements, contracts entered into with others, or company statements of intention with regard to particular deposits should not be reported as cash and cash equivalents.

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