XML 200 R75.htm IDEA: XBRL DOCUMENT v3.8.0.1
Regulatory Matters Regulatory Matters - Annual Electric Distribution/Transmission Filings (Details) - USD ($)
$ in Millions
 3 Months Ended 12 Months Ended 60 Months Ended
Feb. 05, 2018
Jan. 02, 2018
Dec. 19, 2017
Dec. 18, 2017
Nov. 15, 2017
Oct. 27, 2017
Oct. 20, 2017
Oct. 18, 2017
Sep. 11, 2017
Sep. 08, 2017
Aug. 24, 2017
Aug. 17, 2017
Jul. 25, 2017
Jul. 24, 2017
Jul. 14, 2017
Jun. 09, 2017
 [1]
Mar. 30, 2017
Mar. 24, 2017
Mar. 22, 2017
Mar. 08, 2017
Feb. 15, 2017
Feb. 01, 2017
Dec. 17, 2016
Nov. 30, 2016
Nov. 15, 2016
Jul. 29, 2016
May 17, 2016
Feb. 01, 2016
Jun. 30, 2017
Jun. 30, 2016
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2023
Commonwealth Edison Co [Member]                                                                    
Public Utilities, General Disclosures [Line Items]                                                                    
Public Utilities, Requested Rate Increase (Decrease), Amount                               $ (7.0)                             $ 44.0 [2] $ 90.0 [2] $ 68.0 [2]  
Prior Year Revenue Adjustment [2]                                                             (33.0) 4.0 18.0  
Proposed Capital Expenditure [2],[3]                                                             0.0 0.0 0.0  
Public Utilities, Approved Rate Increase (Decrease), Amount                 $ 12.0                                           $ 11.0 [2] $ 94.0 [2] $ 86.0 [2]  
Public Utilities, Approved Equity Capital Structure, Percentage                 6.47%                                           8.43% [4] 8.47% [4] 8.61% [4]  
Public Utilities, Requested Return on Equity, Percentage [5]                                                             11.50% 11.50% 11.50%  
Public Utilities, Approved Return on Equity, Percentage                 8.40%                                                  
Cap on Equity Component of Rate of Return on Common Equity in Federal Energy Regulatory Committee Complaint                                                             55.00%      
Commonwealth Edison Co [Member] | Electric Distribution [Member]                                                                    
Public Utilities, General Disclosures [Line Items]                                                                    
Public Utilities, Requested Rate Increase (Decrease), Amount                                                             $ 78.0 $ 134.0 $ 85.0  
Public Utilities, Approved Rate Increase (Decrease), Amount                                                             18.0 (7.0) (152.0)  
Public Utilities, Requested Rate Increase (Decrease), Amended, Amount                                     $ (18.0)                       $ 96.0 $ 127.0 [6] $ (67.0)  
Public Utilities, Requested Equity Capital Structure, Percentage                                                             6.47% 6.71% 7.05%  
Public Utilities, Approved Equity Capital Structure, Percentage                                                             6.45% 6.69% 7.02%  
Public Utilities, Requested Return on Equity, Percentage                                                             8.40% 8.64% 9.14%  
Public Utilities, Approved Return on Equity, Percentage [7]                                                             8.34% 8.59% 9.09%  
Commonwealth Edison Co [Member] | Maximum [Member] | Electric Distribution [Member]                                                                    
Public Utilities, General Disclosures [Line Items]                                                                    
Public Utilities, Requested Rate Increase (Decrease), Amount                                                             $ 96.0 $ 138.0 $ (50.0)  
Baltimore Gas and Electric Company [Member]                                                                    
Public Utilities, General Disclosures [Line Items]                                                                    
Public Utilities, Requested Rate Increase (Decrease), Amount                                                             31.0 [2] 12.0 [2] 0.0 [2] $ 242.0
Prior Year Revenue Adjustment [2]                                                             3.0 3.0 (3.0)  
Proposed Capital Expenditure                                                             (8.0) [2],[3] 13.0 [2],[3] 13.0 [2],[3] $ 963.0
Public Utilities, Approved Rate Increase (Decrease), Amount [2]                                                             $ 26.0 $ 28.0 $ 10.0  
Public Utilities, Approved Equity Capital Structure, Percentage [4]                                                             7.47% 8.09% 8.46%  
Public Utilities, Requested Return on Equity, Percentage [5]                                                             10.50% 10.50% 11.30%  
Baltimore Gas and Electric Company [Member] | Electric Distribution [Member]                                                                    
Public Utilities, General Disclosures [Line Items]                                                                    
Public Utilities, Requested Rate Increase (Decrease), Amount                                                             $ 116.0      
Public Utilities, Approved Rate Increase (Decrease), Amount                                                   $ 44.0                
Public Utilities, Requested Return on Equity, Percentage                                                   9.75%                
Potomac Electric Power Company [Member]                                                                    
Public Utilities, General Disclosures [Line Items]                                                                    
Public Utilities, Requested Rate Increase (Decrease), Amount [2]                                                             5.0 $ 2.0 $ 10.0  
Prior Year Revenue Adjustment [2]                                                             15.0 (10.0) (3.0)  
Current Year Revenue Adjustment [2],[8]                                                             0.0 (15.0) (2.0)  
Public Utilities, Approved Rate Increase (Decrease), Amount [2]                                                             $ 20.0 $ (23.0) $ 5.0  
Public Utilities, Approved Equity Capital Structure, Percentage [4]                                                             7.92% 7.88% 8.36%  
Public Utilities, Requested Return on Equity, Percentage [5]                                                             10.50% 10.50% 11.30%  
Potomac Electric Power Company [Member] | Electric Distribution [Member]                                                                    
Public Utilities, General Disclosures [Line Items]                                                                    
Public Utilities, Requested Rate Increase (Decrease), Amount $ 11.0 $ 41.0 $ 66.0                             $ 69.0                       $ 86.0        
Public Utilities, Approved Rate Increase (Decrease), Amount           $ 32.0 $ 34.0           $ 37.0                       $ 53.0                  
Public Utilities, Requested Rate Increase (Decrease), Amended, Amount                     $ 67.0                     $ 77.0                        
Public Utilities, Requested Return on Equity, Percentage     10.10%                                                              
Public Utilities, Approved Return on Equity, Percentage             9.50%           9.50%                 10.60%     9.55%                  
Potomac Electric Power Company [Member] | Maximum [Member]                                                                    
Public Utilities, General Disclosures [Line Items]                                                                    
Public Utilities, Requested Return on Equity, Percentage                                                             10.50%      
Delmarva Power and Light Company [Member]                                                                    
Public Utilities, General Disclosures [Line Items]                                                                    
Public Utilities, Requested Rate Increase (Decrease), Amount [2]                                                             $ 6.0 $ 8.0 $ 15.0  
Prior Year Revenue Adjustment [2]                                                             8.0 (10.0) (1.0)  
Current Year Revenue Adjustment [2],[8]                                                             0.0 (12.0) (2.0)  
Public Utilities, Approved Rate Increase (Decrease), Amount [2]                                                             $ 14.0 $ (14.0) $ 12.0  
Public Utilities, Approved Equity Capital Structure, Percentage [4]                                                             7.16% 7.21% 7.80%  
Public Utilities, Requested Return on Equity, Percentage [5]                                                             10.50% 10.50% 11.30%  
Public Utilities, Approved Return on Equity, Percentage                       0.00%                                 0.00%          
Delmarva Power and Light Company [Member] | Electric Distribution [Member]                                                                    
Public Utilities, General Disclosures [Line Items]                                                                    
Public Utilities, Requested Rate Increase (Decrease), Amount               $ 31.0       $ 24.0   $ 27.0                         $ 63.0              
Public Utilities, Approved Rate Increase (Decrease), Amount       $ 13.0                               $ 31.5 $ 38.0   $ 30.0                 $ 32.0    
Public Utilities, Requested Rate Increase (Decrease), Amended, Amount         $ 19.3                             $ 60.0                            
Public Utilities, Approved Return on Equity, Percentage       9.50%                               9.70% 9.60%                          
Atlantic City Electric Company [Member]                                                                    
Public Utilities, General Disclosures [Line Items]                                                                    
Public Utilities, Requested Rate Increase (Decrease), Amount [2]                                                             $ 20.0 8.0 $ 10.0  
Prior Year Revenue Adjustment [2]                                                             22.0 (14.0) 2.0  
Proposed Capital Expenditure                                           $ 29.0           $ 9.0 $ 32.0 $ 19.0        
Current Year Revenue Adjustment [2],[8]                                                             0.0 0.0 0.0  
Public Utilities, Approved Rate Increase (Decrease), Amount [2]                                                             $ 42.0 $ (6.0) $ 12.0  
Public Utilities, Approved Equity Capital Structure, Percentage [4]                                                             8.02% 7.83% 8.51%  
Public Utilities, Requested Return on Equity, Percentage [5]                                                             10.50% 10.50% 11.30%  
Atlantic City Electric Company [Member] | Electric Distribution [Member]                                                                    
Public Utilities, General Disclosures [Line Items]                                                                    
Public Utilities, Requested Rate Increase (Decrease), Amount                                 $ 70.0                                  
Public Utilities, Approved Rate Increase (Decrease), Amount                   $ 43.0                           $ 1.0                    
Public Utilities, Requested Rate Increase (Decrease), Amended, Amount                             $ 73.0                                      
Public Utilities, Approved Return on Equity, Percentage                   9.60%                                                
[1] Reflects higher projected PJM capacity revenues compared to projected energy efficiency costs.
[2] The time period for any challenges to the annual transmission formula rate update flings expired with no challenges submitted
[3] BGE's transmission revenues include a FERC approved dedicated facilities charge to recover the costs of providing transmission service to specifically designated load by BGE.
[4] Represents to the weighted average debt and equity return on transmission rate bases.
[5] As part of the FERC-approved settlement of ComEd’s 2007 transmission rate case, the rate of return on common equity is 11.50%, inclusive of a 50-basis-point incentive adder for being a member of a RTO, and the common equity component of the ratio used to calculate the weighted average debt and equity return for the transmission formula rate is currently capped at 55%. As part of the FERC-approved settlement of the ROE complaint against BGE, Pepco, DPL and ACE, the rate of return on common equity is 10.50%, inclusive of a 50-basis-point incentive adder for being a member of a RTO.
[6] On March 22, 2017, the ICC issued an order approving ComEd's proposal to reduce the 2016 revenue requirement by $18 million, which was reflected in customer rates beginning in April 2017. This reduction is not reflected in the 2016 revenue requirement amounts above.
[7] Includes a reduction of 6 basis points in 2017 and 5 basis points in 2016 and 2015 for a reliability performance metric penalty.
[8] In 2012, PJM terminated the MAPP transmission line construction project planned for the Pepco and DPL service territories. Pursuant to a FERC approved settlement agreement, the abandonment costs associated with MAPP were being recovered in transmission rates over a three-year period that ended in May 2016.