XML 151 R133.htm IDEA: XBRL DOCUMENT v3.6.0.2
Commitments, Guarantees and Contingencies - Other Legal Proceedings (Details) - USD ($)
Dec. 31, 2016
Dec. 06, 2016
Dec. 05, 2016
Dec. 31, 2015
Loss Contingencies [Line Items]        
Nuclear plant decommissioning trusts $ 2,514,000,000     $ 2,282,000,000
Parental support agreement 3,300,000,000      
Nuclear Plant Matters        
Loss Contingencies [Line Items]        
Nuclear plant decommissioning trusts 2,500,000,000      
Additions to parental guarantee associated with funding of decommissioning costs 25,000,000      
NG | Nuclear Plant Matters        
Loss Contingencies [Line Items]        
Nuclear plant decommissioning trusts 10,000,000      
FES        
Loss Contingencies [Line Items]        
Nuclear plant decommissioning trusts 1,552,000,000     $ 1,327,000,000
NG | Parent Support Agreement | FES | Nuclear Plant Matters        
Loss Contingencies [Line Items]        
Parental support agreement 400,000,000      
Revolving Credit Facility | Line of Credit        
Loss Contingencies [Line Items]        
Maximum amount borrowed under revolving credit facility 500,000,000 $ 4,000,000,000 $ 3,500,000,000.0  
Revolving Credit Facility | Line of Credit | Nuclear Plant Matters        
Loss Contingencies [Line Items]        
Maximum amount borrowed under revolving credit facility $ 500,000,000      
Revolving Credit Facility | Line of Credit | FES        
Loss Contingencies [Line Items]        
Maximum amount borrowed under revolving credit facility     $ 900,000,000