v2.4.0.8
Basis of Presentation and Summary of Significant Accounting Policies (Details) (USD $)
In Millions, unless otherwise specified
 3 Months Ended 9 Months Ended
Sep. 30, 2013
Sep. 30, 2012
Sep. 30, 2013
Sep. 30, 2012
Dec. 31, 2012
Accounting Policies [Line Items]          
Held-to-maturity Securities, Restricted $ 24   $ 24   $ 25
Current 185   185   193
Non-current 63   63   60
Total 248   248   253
Cash and cash equivalents subject to project finance facilities and lease agreements 195   195   131
Interest Costs Capitalized 9 10 33 27  
Inventory 325   325   301
Treasury Stock, Value, Acquired, Cost Method     462    
Adjustments Related to Tax Withholding for Share-based Compensation     13    
Debt Service
          
Accounting Policies [Line Items]          
Current 19 [1]   19 [1]   11 [1]
Non-current 43 [1]   43 [1]   41 [1]
Total 62 [1]   62 [1]   52 [1]
Rent Reserve
          
Accounting Policies [Line Items]          
Current 4   4   0
Non-current 0   0   0
Total 4   4   0
Construction Major Maintenance
          
Accounting Policies [Line Items]          
Current 26   26   32
Non-current 11   11   14
Total 37   37   46
Security Project Insurance
          
Accounting Policies [Line Items]          
Current 131   131   101
Non-current 7   7   3
Total 138   138   104
Other
          
Accounting Policies [Line Items]          
Current 5   5   49
Non-current 2   2   2
Total 7   7   51
Geothermal Properties, Gross [Member] | Minimum [Member]
          
Accounting Policies [Line Items]          
Property, Plant and Equipment, Estimated Useful Lives     13 years    
Geothermal Properties, Gross [Member] | Maximum [Member]
          
Accounting Policies [Line Items]          
Property, Plant and Equipment, Estimated Useful Lives     59 years    
Property, Plant and Equipment, Other Types [Member] | Minimum [Member]
          
Accounting Policies [Line Items]          
Property, Plant and Equipment, Estimated Useful Lives     3 years    
Property, Plant and Equipment, Other Types [Member] | Maximum [Member]
          
Accounting Policies [Line Items]          
Property, Plant and Equipment, Estimated Useful Lives     47 years    
Building, Machinery and Equipment, Gross [Member] | Minimum [Member]
          
Accounting Policies [Line Items]          
Property, Plant and Equipment, Estimated Useful Lives     3 years    
Building, Machinery and Equipment, Gross [Member] | Maximum [Member]
          
Accounting Policies [Line Items]          
Property, Plant and Equipment, Estimated Useful Lives     47 years    
Income Statement [Member]
          
Accounting Policies [Line Items]          
Prior Period Reclassification Adjustment   4   9  
Cash Flow Statement [Member]
          
Accounting Policies [Line Items]          
Prior Period Reclassification Adjustment       $ 4  
[1] At September 30, 2013 and December 31, 2012, amounts restricted for debt service included approximately $24 million and $25 million, respectively, of repurchase agreements with a financial institution containing maturity dates greater than one year.