XML 69 R59.htm IDEA: XBRL DOCUMENT v2.4.0.6
Derivative Financial Instruments (Details) (USD $)
 3 Months Ended 6 Months Ended 12 Months Ended 3 Months Ended 6 Months Ended 3 Months Ended 6 Months Ended 6 Months Ended 3 Months Ended 6 Months Ended 3 Months Ended 6 Months Ended 3 Months Ended 6 Months Ended 3 Months Ended 6 Months Ended 3 Months Ended 6 Months Ended 3 Months Ended 6 Months Ended 3 Months Ended 6 Months Ended 3 Months Ended 6 Months Ended 3 Months Ended 6 Months Ended 6 Months Ended 3 Months Ended 6 Months Ended 3 Months Ended 6 Months Ended 3 Months Ended 6 Months Ended 6 Months Ended 6 Months Ended
Jun. 30, 2012
Jun. 30, 2011
Jun. 30, 2012
Jun. 30, 2011
Dec. 31, 2011
Jun. 30, 2012
Operating Revenue [Member]
Jun. 30, 2011
Operating Revenue [Member]
Jun. 30, 2012
Operating Revenue [Member]
Jun. 30, 2011
Operating Revenue [Member]
Jun. 30, 2012
Operating Revenue [Member]
Jun. 30, 2012
Operating Revenue [Member]
Jun. 30, 2012
More Than Two And Within Three Years From Balance Sheet Date [Member]
Dec. 31, 2011
More Than Two And Within Three Years From Balance Sheet Date [Member]
Jun. 30, 2012
Interest Expense [Member]
Jun. 30, 2011
Interest Expense [Member]
Jun. 30, 2012
Total Cash Flow Hedges [Member]
Jun. 30, 2011
Total Cash Flow Hedges [Member]
Jun. 30, 2012
Total Cash Flow Hedges [Member]
Jun. 30, 2011
Total Cash Flow Hedges [Member]
Jun. 30, 2012
Total Cash Flow Hedges [Member]
Operating Revenue [Member]
Jun. 30, 2011
Total Cash Flow Hedges [Member]
Operating Revenue [Member]
Jun. 30, 2012
Total Cash Flow Hedges [Member]
Operating Revenue [Member]
Jun. 30, 2011
Total Cash Flow Hedges [Member]
Operating Revenue [Member]
Jun. 30, 2012
Total Cash Flow Hedges [Member]
Purchased Power [Member]
Jun. 30, 2011
Total Cash Flow Hedges [Member]
Purchased Power [Member]
Jun. 30, 2012
Exelon Generation Co L L C [Member]
GWH
Jun. 30, 2011
Exelon Generation Co L L C [Member]
GWH
Jun. 30, 2012
Exelon Generation Co L L C [Member]
GWH
Jun. 30, 2011
Exelon Generation Co L L C [Member]
GWH
Dec. 31, 2011
Exelon Generation Co L L C [Member]
Jun. 30, 2012
Exelon Generation Co L L C [Member]
Operating Revenue [Member]
Jun. 30, 2011
Exelon Generation Co L L C [Member]
Operating Revenue [Member]
Jun. 30, 2012
Exelon Generation Co L L C [Member]
Operating Revenue [Member]
Jun. 30, 2011
Exelon Generation Co L L C [Member]
Operating Revenue [Member]
Jun. 30, 2011
Exelon Generation Co L L C [Member]
Pro Forma [Member]
Jun. 30, 2011
Exelon Generation Co L L C [Member]
Pro Forma [Member]
Jun. 30, 2012
Exelon Generation Co L L C [Member]
Operating Revenue [Member]
Jun. 30, 2011
Exelon Generation Co L L C [Member]
Operating Revenue [Member]
Jun. 30, 2012
Exelon Generation Co L L C [Member]
Operating Revenue [Member]
Jun. 30, 2011
Exelon Generation Co L L C [Member]
Operating Revenue [Member]
Jun. 30, 2011
Exelon Generation Co L L C [Member]
Operating Revenue [Member]
Pro Forma [Member]
Jun. 30, 2011
Exelon Generation Co L L C [Member]
Operating Revenue [Member]
Pro Forma [Member]
Jun. 30, 2012
Exelon Generation Co L L C [Member]
Purchased Power And Fuel [Member]
Jun. 30, 2011
Exelon Generation Co L L C [Member]
Purchased Power And Fuel [Member]
Jun. 30, 2012
Exelon Generation Co L L C [Member]
Purchased Power And Fuel [Member]
Jun. 30, 2011
Exelon Generation Co L L C [Member]
Purchased Power And Fuel [Member]
Jun. 30, 2011
Exelon Generation Co L L C [Member]
Purchased Power And Fuel [Member]
Pro Forma [Member]
Jun. 30, 2011
Exelon Generation Co L L C [Member]
Purchased Power And Fuel [Member]
Pro Forma [Member]
Jun. 30, 2012
Exelon Generation Co L L C [Member]
Derivative [Member]
Dec. 31, 2011
Exelon Generation Co L L C [Member]
Derivative [Member]
Dec. 31, 2011
Exelon Generation Co L L C [Member]
Cash Flow Hedging [Member]
Jun. 30, 2012
Exelon Generation Co L L C [Member]
Proprietary Trading [Member]
Dec. 31, 2011
Exelon Generation Co L L C [Member]
Proprietary Trading [Member]
Jun. 30, 2012
Exelon Generation Co L L C [Member]
Collateral And Netting [Member]
Dec. 31, 2011
Exelon Generation Co L L C [Member]
Collateral And Netting [Member]
Jun. 30, 2012
Exelon Generation Co L L C [Member]
One Year From Balance Sheet Date [Member]
Jun. 30, 2012
Exelon Generation Co L L C [Member]
More Than One And Within Two Years From Balance Sheet Date [Member]
MW
Jun. 30, 2012
Exelon Generation Co L L C [Member]
More Than Two And Within Three Years From Balance Sheet Date [Member]
Jun. 30, 2012
Exelon Generation Co L L C [Member]
Total Exposure Before Credit Collateral [Member]
Jun. 30, 2012
Exelon Generation Co L L C [Member]
Credit Collateral [Member]
Jun. 30, 2012
Exelon Generation Co L L C [Member]
Net Exposure [Member]
Jun. 30, 2012
Exelon Generation Co L L C [Member]
Number Of Counterparties Greater Than Ten Percent Of Net Exposure [Member]
Jun. 30, 2012
Exelon Generation Co L L C [Member]
Net Exposure Of Counterparties Greater Than Ten Percent Of Net Exposure [Member]
Mar. 11, 2012
Exelon Generation Co L L C [Member]
Energy Related Hedges [Member]
Jun. 30, 2012
Exelon Generation Co L L C [Member]
Energy Related Hedges [Member]
Mar. 31, 2012
Exelon Generation Co L L C [Member]
Energy Related Hedges [Member]
Jun. 30, 2011
Exelon Generation Co L L C [Member]
Energy Related Hedges [Member]
Mar. 31, 2011
Exelon Generation Co L L C [Member]
Energy Related Hedges [Member]
Jun. 30, 2012
Exelon Generation Co L L C [Member]
Energy Related Hedges [Member]
Jun. 30, 2011
Exelon Generation Co L L C [Member]
Energy Related Hedges [Member]
Dec. 31, 2011
Exelon Generation Co L L C [Member]
Energy Related Hedges [Member]
Dec. 31, 2010
Exelon Generation Co L L C [Member]
Energy Related Hedges [Member]
Jun. 30, 2012
Exelon Generation Co L L C [Member]
Energy Related Hedges [Member]
Operating Revenue [Member]
Jun. 30, 2011
Exelon Generation Co L L C [Member]
Energy Related Hedges [Member]
Operating Revenue [Member]
Jun. 30, 2012
Exelon Generation Co L L C [Member]
Energy Related Hedges [Member]
Operating Revenue [Member]
Jun. 30, 2011
Exelon Generation Co L L C [Member]
Energy Related Hedges [Member]
Operating Revenue [Member]
Jun. 30, 2012
Exelon Generation Co L L C [Member]
Energy Related Hedges [Member]
Purchased Power [Member]
Jun. 30, 2011
Exelon Generation Co L L C [Member]
Total Cash Flow Hedges [Member]
Jun. 30, 2012
Exelon Generation Co L L C [Member]
Total Cash Flow Hedges [Member]
Jun. 30, 2012
Commonwealth Edison Co [Member]
Dec. 31, 2011
Commonwealth Edison Co [Member]
Jun. 30, 2012
Commonwealth Edison Co [Member]
Derivative [Member]
Dec. 31, 2011
Commonwealth Edison Co [Member]
Derivative [Member]
Jun. 30, 2012
PECO Energy Co [Member]
Dec. 31, 2011
PECO Energy Co [Member]
Jun. 30, 2012
Baltimore Gas and Electric Company [Member]
Jun. 30, 2012
Other Segment [Member]
Dec. 31, 2011
Other Segment [Member]
Derivative [Member]
Jun. 30, 2012
Other Segment [Member]
Business Intersegment Eliminations [Member]
Dec. 31, 2011
Other Segment [Member]
Business Intersegment Eliminations [Member]
Cash Flow Hedge Accumulated Other Comprehensive Income [Abstract]                                                                                                                                                                                    
Accumulated OCI derivative gain - Beginning Balance                               $ 703,000,000 $ 354,000,000 $ 488,000,000 $ 400,000,000                                                                                         $ 925,000,000 [1],[2] $ 1,166,000,000 [3],[4] $ 925,000,000 [1],[2] $ 941,000,000 [5] $ 1,011,000,000 [6] $ 925,000,000 [1],[2] $ 1,011,000,000 [6]                                        
Effective portion of changes in fair value                               (17,000,000) [7] (64,000,000) 300,000,000 [8] (46,000,000)                                                                                           0 [9]   (106,000,000) [10]   432,000,000 [11] (43,000,000) [12]                                        
Reclassifications from accumulated OCI to net income                                       (139,000,000) (77,000,000) (244,000,000) (140,000,000)                                                                                                   (243,000,000) [13] (143,000,000) [14] (437,000,000) [15] (275,000,000) [16]                            
Ineffective portion recognized in income         1,000,000                                 3,000,000 (5,000,000) 0 (4,000,000)                                                                                                 (4,000,000) 3,000,000 (5,000,000) 0                          
Accumulated OCI derivative gain - Ending Balance                               547,000,000 209,000,000 547,000,000 209,000,000                                                                                           923,000,000 [1],[2] 1,166,000,000 [3],[4] 688,000,000 [17],[6] 941,000,000 [5] 923,000,000 [1],[2] 688,000,000 [17],[6]                                        
Footnotes To Cash Flow Hedge Accumulated Other Comprehensive Income [Abstract]                                                                                                                                                                                    
Unrealized gain (loss) related to fair value of swap contract                                                                                                                                 315,000,000 419,000,000 458,000,000 562,000,000 315,000,000 458,000,000 420,000,000 589,000,000                                    
Unrealized gain (loss) related to fair value of block contract                                                                                                                                               3,000,000                                    
Net gain (loss) related to effective portion of changes in fair value of swap contract                                                                                                                               88,000,000                                                    
Net gain (loss) of reclassifications from accumulated OCI to net income related to the settlements of swap contract                                                                                                                                   (193,000,000) 39,000,000     2,000,000     (104,000,000) (65,000,000)   133,000,000                            
Net gain (loss) of reclassifications from accumulated OCI to net income related to settlements of block contracts                                                                                                                                     1,000,000 2,000,000                                            
Net gains related to interest rate swaps and treasury rate locks                                                                                                                                 (23,000,000) 12,000,000     (23,000,000)   (10,000,000)                                      
Net gains (losses) related to interest rate swaps                                                                                                                                     2,000,000                                              
Net gain (loss) related to effective portion of changes in fair value of treasury rate locks                                                                                                                                 (12,000,000)                         2,000,000 (23,000,000)                      
Other Comprehensive Income, Reclassification Adjustment on Derivatives Included in Net Income, Net of Tax (6,000,000) 0 (6,000,000) 0                                           (6,000,000)   (6,000,000)                                                                                                                            
Credit Risk Exposure [Abstract]                                                                                                                                                                                    
Investment grade                                                                                                                     2,523,000,000 802,000,000 1,721,000,000 0 0                                                      
Non-investment grade                                                                                                                     88,000,000 41,000,000 47,000,000 0 0                                                      
No external ratings - internally rated - investment grade                                                                                                                     552,000,000 16,000,000 536,000,000 1,000,000 286,000,000                                                      
No external ratings - internally rated - non-investment grade                                                                                                                     64,000,000 7,000,000 57,000,000 0 0                                                      
Total                                                                                                                     3,227,000,000 866,000,000 2,361,000,000 1,000,000 286,000,000                                                      
Financial institutions                                                   406,000,000   406,000,000                                                                                                                            
Investor-owned utilities, marketers and power producers                                                   1,091,000,000   1,091,000,000                                                                                                                            
Energy cooperative and municipalities                                                   775,000,000   775,000,000                                                                                                                            
Other                                                   89,000,000   89,000,000                                                                                                                            
Total                                                   2,361,000,000   2,361,000,000                                                                                                                            
Derivative Instruments Gain Loss Recognized In Income Net [Abstract]                                                                                                                                                                                    
Gain on swaps/borrowings                           (2,000,000) [18] 0 [18]                                                                                                                                                      
Loss on swaps/borrowings                           (3,000,000) [18] 0 [18]                                                                                                                                                      
Percent Of Expected Generation Being Hedged [Abstract]                                                                                                                                                                                    
Minimum range of expected generation hedged                                                                                                               99.00% 79.00% 46.00%                                                                
Maximum range of expected generation hedged                                                                                                               102.00% 82.00% 49.00%                                                                
Swap Contract Volumes [Abstract]                                                                                                                                                                                    
Swap contract volumes                                                                                                                 3,000                                                                  
Percent Of Gas Purchases Being Hedged [Abstract]                                                                                                                                                                                    
Maximum percentage of natural gas purchases hedged                                                                                                                                                                       30.00%            
Proprietary Trading Volumes [Abstract]                                                                                                                                                                                    
Proprietary trading activities volume                                                   4,248 1,496 6,077 2,829                                                                                                                          
Cost Of Capital Strategies [Abstract]                                                                                                                                                                                    
Pre-tax net income impact associated with a hypothetical 10% increase in interest rates - exclusive upper bound     2,000,000                                                 2,000,000                                                                                                               2,000,000   2,000,000        
Interest Rate Risk - Fair Value Hedges [Abstract]                                                                                                                                                                                    
Notional amounts of fair value hedges outstanding related to interest rate swaps                       650,000,000 100,000,000                                                                                                                                                          
Fair value assets                       55,000,000 14,000,000                                                                                                                                                          
Interest rate swaps previously held by acquiree 550,000,000   550,000,000                                                                                                                                                                              
Fair value of interest rate swaps from merger acquiree 44,000,000   44,000,000                                                                                                                                                                              
Notional amount of interest rate swaps acquired from merger 150,000,000   150,000,000                                                                                                                                                                              
Fair value of interest rate swaps acquired from merger 5,000,000   5,000,000                                                                                                                                                                              
Interest Rate Risk - Cash Flow Hedges [Abstract]                                                                                                                                                                                    
DOE interest rate swap     485,000,000                                                                                                                                                                              
Percentage of interest rate swap in relation to DOE guarantee                                                   75   75                                                                                                                            
Notional amount of interest rate swap DOE advance                                                   52,000,000   52,000,000                                                                                                                            
Percent of DOE loan advance offset                                                       75.00%                                                                                                                            
Notional amount of remaining cash flow hedges                                                   433,000,000   433,000,000                                                                                                                            
Notional amounts on forward starting interest rate swaps                                                   31,000,000   31,000,000                                                                                                                            
Noncurrent Derivative Liability Forward Starting Interest Rate Swaps                                                   4,000,000   4,000,000                                                                                                                            
Cash Flow Hedge Activity Impact [Abstract]                                                                                                                                                                                    
Net unrealized pre-tax gain (loss) on effective cash flow hedges                                                       1,928,000,000                                                                                                                            
Net unrealized pre-tax gain (loss) on effective cash flow hedges related to swap contract                                                       693,000,000                                                                                                                            
Expected reclassification from accumulated other comprehensive income to results of operations                                                                                                               1,105,000,000                                                                    
Expected reclassification from accumulated other comprehensive income to results of operations related to fair value of swap contracts                                                       521,000,000                                                                                                                            
Cash flow hedge activity impact on pre-tax net income based on reclassification adjustment from accumulated other comprehensive income 230,000,000 127,000,000 403,000,000 231,000,000                                           402,000,000 237,000,000 722,000,000 454,000,000                                                                                                                          
Change in cash flow hedge ineffectiveness 0   (5,000,000)                                             0   (5,000,000)                                                                                                                            
Cash flow hedge ineffectiveness adjustment to accumulated other comprehensive income 0   0                                             0   0                                                                                                                            
Due From Related Parties [Abstract]                                                                                                                                                                                    
Net receivable from electric utility                                                   61,000,000   61,000,000                                                                                                                            
Net receivable from affiliated electric and gas utility                                                   59,000,000   59,000,000                                                                                                                   11,000,000        
Natural Gas Supply And Management Agreement Credit Exposure [Abstract]                                                                                                                                                                                    
Natural gas asset manager parental guarantee                                                                                                                                                                       14,000,000            
Credit exposure under natural gas supply and management agreements                                                                                                                                                                       4,000,000            
Credit exposure under off system sales                                                                                                                                                                           2,000,000        
Collateral And Contingent Related Features [Abstract]                                                                                                                                                                                    
Aggregate fair value of derivatives with credit-risk-related contingent features (4,126,000,000) [19]   (4,126,000,000) [19]   (1,014,000,000) [19]                                                                                                                                                                          
Contractual right of offset related to derivative assets 3,235,000,000 [20]   3,235,000,000 [20]   928,000,000 [20]                                                                                                                                                                          
Net liability position after contractual right of offset (891,000,000) [21]   (891,000,000) [21]   (86,000,000) [21]                                                                                                                                                                          
Incremental collateral for loss of investment grade credit rating                                                   2,375,000,000   2,375,000,000   1,612,000,000                                                                                                           36,000,000   54,000,000        
Cash collateral held                                                   1,007,000,000   1,007,000,000   542,000,000                                                                                                                        
Cash collateral posted                                                   697,000,000   697,000,000                                                                                                                            
Letters of credit held                                                   152,000,000   152,000,000   89,000,000                                                                                                                        
Letters of credit posted                                                   1,189,000,000   1,189,000,000                                                                                                                            
Swap Contract Collateral Posting Limit [Abstract]                                                                                                                                                                                    
Swap contract collateral posting limit                                                   200,000,000   200,000,000                                                                                                       200,000,000                    
Credit Derivative, Collateral Held Directly or by Third Parties Monetary Amount                                                                                                                                                               20,000,000                    
Fair value of interest-rate swap in asset position                                                   18,000,000   18,000,000                                                                                                                            
Master Netting Arrangements [Abstract]                                                                                                                                                                                    
Cash collateral received not offset against net derivative positions                                                   13,000,000   13,000,000   2,000,000                                                                                                                        
Derivatives Fair Value [Line Items]                                                                                                                                                                                    
Mark-to-market derivative assets (current assets) 1,150,000,000   1,150,000,000   432,000,000                                         1,150,000,000 [22]   1,150,000,000 [22]   432,000,000 [23]                                     4,863,000,000 [24] 1,195,000,000 438,000,000 [25] 5,360,000,000 217,000,000 (9,073,000,000) [26] (1,418,000,000) [26]                                                     0 [24] 0       0 [24] 0   0
Mark-to-market derivative assets with affiliate (current assets) 0   0   0                                         506,000,000 [22]   506,000,000 [22]   503,000,000 [23]                                     506,000,000 [24] 0 503,000,000 [25] 0 0 0 0                                                     0 [24] 0         0 (506,000,000) [24] (503,000,000) [25]
Mark-to-market derivative assets (noncurrent assets) 1,140,000,000   1,140,000,000   650,000,000                                         1,140,000,000 [22]   1,140,000,000 [22]   635,000,000 [23]                                     2,797,000,000 [24] 582,000,000 419,000,000 [25] 1,664,000,000 71,000,000 (3,321,000,000) [26] (437,000,000) [26]                                                     0 [24] 0         15,000,000 0 [24] 0
Mark-to-market derivative assets with affiliate (noncurrent assets)         0                                         0   0   191,000,000 [23]                                       0 191,000,000 [25]   0   0                                                       0         0   (191,000,000) [25]
Total mark-to-market derivative assets 2,290,000,000   2,290,000,000   1,082,000,000                                         2,796,000,000 [22]   2,796,000,000 [22]   1,761,000,000 [23]                                     8,166,000,000 [24] 1,777,000,000 1,551,000,000 [25] 7,024,000,000 288,000,000 (12,394,000,000) [26] (1,855,000,000) [26]                                                     0 [24] 0         15,000,000 (506,000,000) [24] (694,000,000) [25]
Mark-to-market derivative liabilities (current liabilities) (810,000,000)   (810,000,000)   (112,000,000)                                         (791,000,000) [22]   (791,000,000) [22]   (103,000,000) [23]                                     (4,405,000,000) [24] (965,000,000) (9,000,000) [25] (5,360,000,000) (194,000,000) 8,974,000,000 [26] 1,065,000,000 [26]                                                     (19,000,000) [27] (9,000,000) [27] 0 0     0 0 [24] 0
Mark-to-market derivative liability with affiliate (current liability) 0   0   0                                         0   0   0                                     0 [24] 0 0 0 0 0 0                                                 (506,000,000) (503,000,000) (506,000,000) [24] (503,000,000) [25] 0 0     0 506,000,000 [24] 503,000,000 [25]
Mark-to-market energy derivative liabilities (noncurrent liabilities) (507,000,000)   (507,000,000)   (107,000,000)                                         (415,000,000) [22]   (415,000,000) [22]   (10,000,000) [23]                                     (1,903,000,000) [24] (186,000,000) (4,000,000) [25] (1,609,000,000) (70,000,000) 3,097,000,000 [26] 250,000,000 [26]                                                     (92,000,000) [27] (97,000,000) [27]         0 0 [24] 0
Mark-to-market derivative liabilities with affiliate (noncurrent liabilities)         0                                                 0                                       0 0   0   0                                                 0 (191,000,000)   (191,000,000) [25]         0   191,000,000 [25]
Total mark-to-market derivative liabilities (1,317,000,000)   (1,317,000,000)   (219,000,000)                                         (1,206,000,000) [22]   (1,206,000,000) [22]   (113,000,000) [23]                                     (6,308,000,000) [24] (1,151,000,000) (13,000,000) [25] (6,969,000,000) (264,000,000) 12,071,000,000 [26] 1,315,000,000 [26]                                                     (617,000,000) [24],[27] (800,000,000) [25],[27]         0 506,000,000 [24] 694,000,000 [25]
Total mark-to-market derivative net assets (liabilities) 973,000,000   973,000,000   863,000,000                                         1,590,000,000 [22]   1,590,000,000 [22]   1,648,000,000 [23]                                     1,858,000,000 [24] 626,000,000 1,538,000,000 [25] 55,000,000 24,000,000 (323,000,000) [26] (540,000,000) [26]                                                     (617,000,000) [24],[27] (800,000,000) [25],[27]         15,000,000 0 [24] 0
Footnotes To Derivative Instruments In Statement Of Financial Position Fair Value [Abstract]                                                                                                                                                                                    
Fair value swap contract current asset                                                                                                 506,000,000 503,000,000                                                                                
Fair value swap contract noncurrent asset                                                                                                   191,000,000                                                                                
Fair value swap contract current liability                                                                                                                                                                   506,000,000 503,000,000              
Fair value swap contract noncurrent liability                                                                                                                                                                     191,000,000              
Current assets collateral                                                   233,000,000   233,000,000                                                     338,000,000                                                                      
Noncurrent assets collateral                                                   424,000,000   424,000,000                                                     187,000,000                                                                      
Current liabilities collateral                                                   (134,000,000)   (134,000,000)                                                     15,000,000                                                                      
Noncurrent liabilities collateral                                                   (200,000,000)   (200,000,000)                                                     0                                                                      
Total cash collateral received net of cash collateral posted                                                   323,000,000   323,000,000                                                     540,000,000                                                                      
Noncurrent liability interest rate swap AVSR                                                                                                     19,000,000                                                                              
Other Derivatives Not Designated As Hedging Instruments [Abstract]                                                                                                                                                                                    
Change in fair value 72,000,000   176,000,000             16,000,000 [28] 27,000,000 [28]                             56,000,000 (4,000,000) 149,000,000 (7,000,000)           (4,000,000) (7,000,000) 44,000,000 0 177,000,000 0 12,000,000 13,000,000 12,000,000 (4,000,000) (28,000,000) (7,000,000) (16,000,000) (20,000,000)                                                                                    
Reclassification to realized at settlement 134,000,000   106,000,000             (10,000,000) [28] (10,000,000) [28]                             144,000,000 (126,000,000) 116,000,000 (273,000,000)           (126,000,000) (273,000,000) (54,000,000) 0 (109,000,000) 0 (137,000,000) (271,000,000) 198,000,000 (126,000,000) 225,000,000 (273,000,000) 11,000,000 (2,000,000)                                                                                    
Net mark-to-market gains (losses) 206,000,000   282,000,000             6,000,000 [28] 17,000,000 [28]                             200,000,000 (130,000,000) [29] 265,000,000 (280,000,000) [29]           (130,000,000) [29] (280,000,000) [29] (10,000,000) 0 [29] 68,000,000 0 [29] (125,000,000) [29] (258,000,000) [29] 210,000,000 (130,000,000) [29] 197,000,000 (280,000,000) [29] (5,000,000) [29] (22,000,000) [29]                                                                                    
Proprietary Trading Activities [Abstract]                                                                                                                                                                                    
Change in fair value           12,000,000 16,000,000 14,000,000 19,000,000                                           12,000,000 16,000,000 14,000,000 19,000,000                                                                                                                
Reclassification to realized at settlement           31,000,000 (7,000,000) 32,000,000 (12,000,000)                                           31,000,000 (7,000,000) 32,000,000 (12,000,000)                                                                                                                
Net mark-to-market gains (losses)           $ 43,000,000 $ 9,000,000 $ 46,000,000 $ 7,000,000                                           $ 43,000,000 $ 9,000,000 $ 46,000,000 $ 7,000,000                                                                                                                
[1] Includes $315 million and $420 million of gains, net of taxes, related to the fair value of the five-year financial swap contract with ComEd, as of June 30, 2012 and December 31, 2011.
[2] Excludes $23 million of losses and $10 million of losses, net of taxes, related to interest rate swaps and treasury locks for the six months ended June 30, 2012 and year ended December 31, 2011, respectively.
[3] Includes $315 million and $419 million of gains, net of taxes, related to the fair value of the five-year financial swap contract with ComEd, as of June 30, 2012 and March 31, 2012, respectively.
[4] Excludes $23 million of losses and $12 million of gains net of taxes, related to interest rate swaps and treasury rate locks for the three months ended June 30, 2012
[5] Includes $458 million and $562 million of gains, net of taxes, related to the fair value of the five-year financial swap contract with ComEd, $1 million and $2 million of gains, net of taxes, related to the fair value of the block contracts with PECO as of June 30, 2011 and March 31, 2011, respectively.
[6] Includes $458 million and $589 million of gains, net of taxes, related to the fair value of the five-year financial swap contract with ComEd, and $1 million and $3 million of gains, net of taxes, related to the fair value of the block contracts with PECO as of June 30, 2011 and December 31, 2010, respectively.
[7] Includes $12 million of losses, net of taxes, at Generation related to the effective portion of changes in fair value of interest rate swaps and treasury rate locks.
[8] Includes $23 million of losses, net of taxes, related to the effective portion of changes in fair value of interest rate swaps and treasury rate locks.
[9] Due to the de-designation of all commodity cash flow positions prior to the merger date, there are no changes in fair value.
[10] Includes a $39 million gain, net of taxes, related to the effective portion of changes in fair value of the five-year financial swap contract with ComEd for the three months ended June 30, 2011. The PECO block contracts were designated as normal sales as of May 31, 2010. As such, there were no effective changes in fair value of the block contracts with PECO for the three months ended June 30, 2011 as the mark-to-market balances previously recorded will be amortized over the term of the contract.
[11] Includes $88 million of gains, net of taxes, related to the effective portion of changes in fair value of the five-year financial swap contract with ComEd through the date of de-designation prior to the merger.
[12] Includes a $2 million of gains, net of taxes, related to the effective portion of changes in fair value of the five-year financial swap contract with ComEd for the six months ended June 30, 2011. The PECO block contracts were designated as normal sales as of May 31, 2010. As such, there were no additional effective changes in fair value of PECO's block contracts as the mark-to-market balances previously recorded are being amortized over the term of the contract.
[13] Includes $104 million of losses, net of taxes, reclassified from accumulated OCI to recognize gains in net income related to the settlements of the five-year financial swap contract with ComEd.
[14] Includes a $65 million loss, net of taxes, reclassified from accumulated OCI to recognize gains in net income related to the settlements of the five-year financial swap contract with ComEd, and a $1 million loss, net of taxes, reclassified from accumulated OCI to recognize gains in net income related to the fair value of the block contracts with PECO for the three months ended June 30, 2011.
[15] Includes $193 million of losses, net of taxes, reclassified from accumulated OCI to recognize gains in net income related to the settlements of the five-year financial swap contract with ComEd
[16] Includes a $133 million loss, net of taxes, reclassified from accumulated OCI to recognize gains in net income related to the settlements of the five-year financial swap contract with ComEd and a $2 million loss, net of taxes, reclassified from accumulated OCI to recognize gains in net income related to the fair value of the block contracts with PECO for the six months ended June 30, 2011
[17] Excludes $2 million of gains, net of taxes, related to interest rate swaps.
[18] For the six months ended June 30, 2012, the loss on the swaps in the table above includes pre-tax losses of $5 million, not related to changes in benchmark interest rates and is excluded from hedge ineffectiveness.
[19] Amount represents the gross fair value of out-of-the-money derivative contracts containing credit-risk-related contingent features that are not fully collateralized by posted cash collateral on an individual, contract-by-contract basis ignoring the effects of master netting agreements.
[20] Amount represents the offsetting fair value of in-the-money derivative contracts under legally enforceable master netting agreements with the same counterparty, which reduces the amount of any liability for which a Registrant could potentially be required to post collateral.
[21] Amount represents the net fair value of out-of-the-money derivative contracts containing credit-risk related contingent features after considering the mitigating effects of offsetting positions under master netting arrangements and reflects the actual net liability upon which any potential contingent collateral obligations would be based.
[22] Current and noncurrent assets are shown net of collateral of $233 million and $424 million, respectively, and current and noncurrent liabilities are shown inclusive of collateral of $(134) million and $(200) million, respectively. The total cash collateral received, net of cash collateral posted and offset against mark-to-market assets and liabilities was $323 million at June 30, 2012.
[23] Current and noncurrent assets are shown net of collateral of $338 million and $187 million, respectively, and current and noncurrent liabilities are shown inclusive of collateral of $15 million and $0 million, respectively. The total cash collateral received net of cash collateral posted and offset against mark-to-market assets and liabilities was $540 million at December 31, 2011.
[24] Includes current assets for Generation and current liabilities for ComEd of $506 million related to the fair value of the five-year financial swap contract between Generation and ComEd, as described above.
[25] Includes current and noncurrent assets for Generation and current and noncurrent liabilities for ComEd of $503 million and $191 million, respectively, related to the fair value of the five-year financial swap contract between Generation and ComEd, as described above. For Generation excludes $19 million noncurrent liability relating to an interest rate swap in connection with a loan agreement to fund Antelope Valley as discussed above.
[26] Represents the netting of fair value balances with the same counterparty and the application of collateral.
[27] Includes current and noncurrent liabilities relating to floating-to-fixed energy swap contracts with unaffiliated suppliers.
[28] Prior to the merger, the five-year financial swap contract between Generation and ComEd was de-designated. As a result, all prospective changes in fair value are recorded to operating revenues and eliminated in consolidation.
[29] Exelon and Generation have historically presented mark-to-market gains and losses within purchased power expense for all non-trading, energy-related derivatives that were not accounted for as cash flow hedges. In 2011, Exelon and Generation classified the mark-to-market gains and losses for contracts, where the underlying hedged transaction was an expected sale to hedge power, to operating revenues