XML 87 R48.htm IDEA: XBRL DOCUMENT v3.4.0.3
Commitments and Contingencies (Legal Matters) (Details)
 1 Months Ended 3 Months Ended
Dec. 31, 2015
claim
Dec. 31, 2015
claim
Apr. 30, 2015
project
Aug. 31, 2014
project
May. 31, 2014
project
Jul. 31, 2013
project
Mar. 31, 2013
USD ($)
claim
Jul. 31, 2012
USD ($)
plaintiff
Apr. 30, 2012
utility
Mar. 31, 2016
USD ($)
Nov. 30, 2014
USD ($)
Legal Matters - Gas Supply Litigation (Numeric) [Abstract]                      
Number of separate claims included in the complaint against PPL Montana | claim             39        
Average requested amount, per day per violation, of injunctive relief and civil penalties             $ 36,000        
Amount of civil penalties to be used for beneficial mitigation projects             $ 100,000        
Estimated number of post-2000 projects alleged not to be in compliance with the Clean Air Act | project           40          
Number of plant projects that had claims dismissed under alleged Clean Air Act violations   2     3            
Number of plant projects included in a second amended complaint under alleged Clean Air Act violations | project       8              
Number of plant projects with remaining claims to be pursued by plaintiffs 4   4                
Number of plants with more preferable legal standards claims | claim 2                    
Regulatory Issues - Maryland Capacity Order (Numeric) [Abstract]                      
Number electric utilities ordered to enter into long term contracts | utility                 3    
Regulatory Issues - Electric - Reliability Standards (Numeric) [Abstract]                      
Maximum per day penalties for reliability violations                   $ 1,000,000  
Pacific Northwest Markets                      
Regulatory Issues - Pacific Northwest Markets (Numeric) [Abstract]                      
Number of parties claiming refunds | plaintiff               2      
Claim sought               $ 23,000,000      
Remaining claim outstanding                   $ 50,000,000  
Pending Litigation | Topaz Gas Supply                      
Legal Matters - Gas Supply Litigation (Numeric) [Abstract]                      
Loss Contingency, Estimate of Possible Loss                     $ 7,000,000
Settled litigation | Pacific Northwest Markets                      
Regulatory Issues - Pacific Northwest Markets (Numeric) [Abstract]                      
Number of parties claiming refunds | plaintiff               1      
Settlement amount reached with one of the parties               $ 75,000