XML 70 R38.htm IDEA: XBRL DOCUMENT v3.3.1.900
Summary of Significant Accounting Policies General and Basis of Presentation (Details)
People in Millions, $ in Millions
 3 Months Ended 12 Months Ended
Dec. 31, 2015
USD ($)
variable_interest_entities
People
Dec. 31, 2014
USD ($)
Sep. 30, 2016
USD ($)
Sep. 30, 2015
USD ($)
Sep. 30, 2014
USD ($)
General and Basis of Presentation          
Population of TVA's service area | People 9        
Amount of appropriation investment that was repaid         $ 1,000
Number of variable interest entities | variable_interest_entities 3        
Reclassification from Environmental cleanup costs-Kingston ash spill-non cash to Other, net   $ 12      
Reclassification from Environmental cleanup costs-Kingston ash spill to Other, net   (9)      
Reclassification from Other Long-Term Assets to Long-Term Debt, Net $ 80        
Reclassification from Other Long-Term Assets to Long-term Power Bonds, Net 67        
Reclassification from Other Long-Term Assets to Long-Term Variable Interest Entities, Net 13        
Allowance for uncollectible accounts, accounts receivable 1     $ 1  
Loans receivable 124     117  
Loans receivable, allowance 8     $ 8  
Depreciation expense 364 $ 380      
Change in depreciation 22        
Total estimated amount of BLEU payments 162        
Payments attributable to BLEU fuel program 131        
BLEU fuel obligation $ 12        
Scenario, Forecast          
General and Basis of Presentation          
Change in depreciation     $ 83