v2.4.0.6
Income Taxes (Income Tax Expense (Benefit)) (Details) (USD $)
 3 Months Ended 9 Months Ended 12 Months Ended
Sep. 30, 2012
Sep. 30, 2011
Sep. 30, 2012
Sep. 30, 2011
Dec. 31, 2011
Income Tax Disclosure [Abstract]          
Operating Loss Carryforwards Available To Offset Future Income         $ 6,300,000,000
One time tax benefit from consolidation       76,000,000  
Income tax expense (benefit) 81,000,000 20,000,000 23,000,000 (45,000,000) [1]  
Effective Income Tax Rate, Continuing Operations 16.00% 10.00% 19.00% 20.00%  
Income Tax Expense (Benefit), Intraperiod Tax Allocation 3,000,000 36,000,000 7,000,000 20,000,000  
Other Comprehensive Income (Loss), Tax (3,000,000) (34,000,000) (7,000,000) (18,000,000)  
NOLs expected to expire unutilized related to pre-emergence date NOLs         640,000,000
NOLs expected to expire unutilized due to carryforward time constraints     50,000,000    
Percent Decline In Market Cap Required To Trigger Transfer Restrictions 35.00%   35.00%    
Emergence Date Capitalization 8,600,000,000   8,600,000,000    
Percent Change in Ownership Required To Trigger Transfer Restrictions 25.00%   25.00%    
Holders with ownership that could be affected by transfer restrictions 5.00%   5.00%    
Unrecognized Tax Benefits 92,000,000   92,000,000    
Unrecognized Tax Benefits that Would Impact Effective Tax Rate 47,000,000   47,000,000    
Unrecognized Tax Benefits Resulting in Net Operating Loss Carryforward 45,000,000   45,000,000    
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued 23,000,000   23,000,000    
Unrecognized Tax Benefits, Increases Resulting from Prior Period Tax Positions     18,000,000    
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Estimated Range of Change, Lower Bound 0   0    
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Estimated Range of Change, Upper Bound 23,000,000   23,000,000    
Tax refund due to foreign dividend income treatment 10,000,000   10,000,000    
Tax refund plus accrued interest due to foreign dividend income treatment 13,000,000   13,000,000    
Accrued interest on foreign dividend refund $ 3,000,000   $ 3,000,000    
[1] approximately $76 million related to the election to consolidate our CCFC and Calpine groups for federal income tax reporting purposes for the nine months ended September 30, 2011.