XML 42 R43.htm IDEA: XBRL DOCUMENT v3.2.0.727
Summary of Significant Accounting Policies General and Basis of Presentation (Details)
People in Millions, $ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2015
USD ($)
Jun. 30, 2015
USD ($)
variable_interest_entities
People
Jun. 30, 2014
USD ($)
Jun. 30, 2015
USD ($)
variable_interest_entities
People
Jun. 30, 2014
USD ($)
Sep. 30, 2014
USD ($)
General and Basis of Presentation            
Population of TVA's service area | People   9   9    
Amount of appropriation investment that was be repaid           $ 1,000
Number of variable interest entities | variable_interest_entities   3   3    
Reclassification from Environmental cleanup costs-Kingston ash spill-non cash to Other, net       $ 51    
Reclassification from Environmental cleanup costs-Kingston ash spill to Other, net       (65)    
Reclassification to Other, net from Environmental cleanup costs-Kingston ash spill-non cash and Environmental cleanup costs-Kingston ash spill       $ (14)    
Period of time for customers to fulfill payment arrangements       90 days    
Allowance for uncollectible accounts, accounts receivable   $ 1   $ 1   1
Loans receivable   99   99   81
Loans receivable, allowance   9   9   $ 9
Depreciation expense   462 $ 391 1,200 $ 1,100  
Accelerated depreciation   81   81    
Total possible amount of payments   162   162    
Payments attributable to BLEU fuel program   131   131    
BLEU fuel obligation   $ 12   $ 12    
Scenario, Forecast [Member]            
General and Basis of Presentation            
Accelerated depreciation $ 137