v3.7.0.1
Basis of Presentation and Summary of Significant Accounting Policies (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2017
Jun. 30, 2016
Jun. 30, 2017
Jun. 30, 2016
Dec. 31, 2016
Accounting Policies [Line Items]          
Goodwill, Beginning Balance     $ 187    
Goodwill, Purchase Accounting Adjustments [1]     6    
Goodwill, Ending Balance $ 242   242    
Current 105   105   $ 173
Non-current 28   28   15
Total 133   133   188
Interest costs capitalized 6 $ 5 13 $ 9  
Transfer of Financial Assets Accounted for as Sales, Fair Value of Derecognized Assets 198   198   211
Continuing Involvement with Continued to be Recognized Transferred Financial Assets, Amount Outstanding 35   35   32
Trade Receivables Sold     1,100    
Cash Flows Between Transferor and Transferee, Proceeds from New Transfers     1,100    
Debt service          
Accounting Policies [Line Items]          
Current 18   18   11
Non-current 8   8   8
Total 26   26   19
Construction major maintenance          
Accounting Policies [Line Items]          
Current 21   21   45
Non-current 19   19   6
Total 40   40   51
Security project insurance          
Accounting Policies [Line Items]          
Current 63   63   114
Non-current 0   0   0
Total 63   63   114
Other          
Accounting Policies [Line Items]          
Current 3   3   3
Non-current 1   1   1
Total 4   $ 4   $ 4
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     58 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     46 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     46 years    
Texas [Member]          
Accounting Policies [Line Items]          
Goodwill, Beginning Balance     $ 31    
Goodwill, Ending Balance 30   30    
East [Member]          
Accounting Policies [Line Items]          
Goodwill, Beginning Balance     88    
Goodwill, Purchase Accounting Adjustments [1]     11    
Goodwill, Ending Balance 148   148    
West [Member]          
Accounting Policies [Line Items]          
Goodwill, Beginning Balance     68    
Goodwill, Ending Balance $ 64   64    
Calpine Solutions [Member] | Texas [Member]          
Accounting Policies [Line Items]          
Goodwill, Purchase Accounting Adjustments [1]     (1)    
Calpine Solutions [Member] | East [Member]          
Accounting Policies [Line Items]          
Goodwill, Purchase Accounting Adjustments     (5)    
Calpine Solutions [Member] | West [Member]          
Accounting Policies [Line Items]          
Goodwill, Purchase Accounting Adjustments [1]     (4)    
North American Power [Member]          
Accounting Policies [Line Items]          
Goodwill, Acquired During Period     49    
North American Power [Member] | Texas [Member]          
Accounting Policies [Line Items]          
Goodwill, Acquired During Period     0    
North American Power [Member] | East [Member]          
Accounting Policies [Line Items]          
Goodwill, Acquired During Period     49    
Goodwill, Purchase Accounting Adjustments     16    
North American Power [Member] | West [Member]          
Accounting Policies [Line Items]          
Goodwill, Acquired During Period     $ 0    
[1] The purchase price allocation adjustment in the East segment represents adjustments of $16 million for North American Power and $(5) million for Calpine Solutions.