XML 177 R127.htm IDEA: XBRL DOCUMENT v3.4.0.3
Segment Information - Generation Total Revenues Net of Purchased Power and Fuel Expense (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2016
Mar. 31, 2015
Segment Reporting Information [Line Items]    
Revenues $ 7,573 $ 8,830
Derivative, Gain on Derivative   (7)
Unrealized Gain (Loss) on Derivatives 107 91
Generation Total Consolidated Group [Member]    
Segment Reporting Information [Line Items]    
Segment Reporting Information Revenue Net of Purchase Power And Fuel 2,297 2,407
Revenues 4,739 5,840
Generation Mid Atlantic [Member]    
Segment Reporting Information [Line Items]    
Segment Reporting Information Revenue Net of Purchase Power And Fuel 841 787
Revenues 1,520 1,513
Generation Midwest [Member]    
Segment Reporting Information [Line Items]    
Segment Reporting Information Revenue Net of Purchase Power And Fuel 718 703
Revenues 1,095 1,276
Generation New England [Member]    
Segment Reporting Information [Line Items]    
Segment Reporting Information Revenue Net of Purchase Power And Fuel 81 158
Revenues 470 859
Generation New York [Member]    
Segment Reporting Information [Line Items]    
Segment Reporting Information Revenue Net of Purchase Power And Fuel 130 189
Revenues 203 310
Generation ERCOT [Member]    
Segment Reporting Information [Line Items]    
Segment Reporting Information Revenue Net of Purchase Power And Fuel 61 55
Revenues 163 180
Generation Other Regions [Member]    
Segment Reporting Information [Line Items]    
Segment Reporting Information Revenue Net of Purchase Power And Fuel 76 46
Revenues 223 214
Other Segments [Member] | Scenario, Adjustment [Member]    
Segment Reporting Information [Line Items]    
Segment Reporting Information Revenue Net of Purchase Power And Fuel   9
Generation All Other Segments [Member]    
Segment Reporting Information [Line Items]    
Amortization Of Intangible Assets Related To Commodity Contracts For Revenue Net Purchased Power And Fuel 19 38
Segment Reporting Information Revenue Net of Purchase Power And Fuel 390 469
Revenues 1,065 1,488
Derivative, Gain on Derivative 63 154
Unrealized Gain (Loss) on Derivatives 103 162
Generation All Other Segments [Member] | Scenario, Adjustment [Member]    
Segment Reporting Information [Line Items]    
Segment Reporting Information Revenue Net Of Purchase Power And Fuel From External Customers   (5)
Intersegment RNF   (4)
Revenues   (43)
Generation Reportable Segments Total [Member]    
Segment Reporting Information [Line Items]    
Segment Reporting Information Revenue Net of Purchase Power And Fuel 1,907 1,938
Revenues 3,674 4,352
Generation Reportable Segments Total [Member] | Scenario, Adjustment [Member]    
Segment Reporting Information [Line Items]    
Intersegment RNF   4
Segment Reporting Information Revenue Net of Purchase Power And Fuel   5
Revenues   43
Intersegment Eliminations [Member] | Generation Total Consolidated Group [Member]    
Segment Reporting Information [Line Items]    
Intersegment RNF 0 0
Revenues 0 0
Intersegment Eliminations [Member] | Generation Mid Atlantic [Member]    
Segment Reporting Information [Line Items]    
Intersegment RNF 9 (21)
Revenues [1] (12) (43)
Intersegment Eliminations [Member] | Generation Midwest [Member]    
Segment Reporting Information [Line Items]    
Intersegment RNF 3 (6)
Revenues 6 0
Intersegment Eliminations [Member] | Generation New England [Member]    
Segment Reporting Information [Line Items]    
Intersegment RNF (5) (24)
Revenues (1) (6)
Intersegment Eliminations [Member] | Generation New York [Member]    
Segment Reporting Information [Line Items]    
Intersegment RNF (11) 20
Revenues [1] (15) 3
Intersegment Eliminations [Member] | Generation ERCOT [Member]    
Segment Reporting Information [Line Items]    
Intersegment RNF (20) (33)
Revenues 0 (1)
Intersegment Eliminations [Member] | Generation Other Regions [Member]    
Segment Reporting Information [Line Items]    
Intersegment RNF (10) (26)
Revenues [2] 1 2
Intersegment Eliminations [Member] | Generation All Other Segments [Member]    
Segment Reporting Information [Line Items]    
Intersegment RNF 34 90
Revenues [3] 21 45
Intersegment Eliminations [Member] | Generation Reportable Segments Total [Member]    
Segment Reporting Information [Line Items]    
Intersegment RNF (34) (90)
Revenues (21) (45)
Operating Segments [Member] | Generation Total Consolidated Group [Member]    
Segment Reporting Information [Line Items]    
Segment Reporting Information Revenue Net Of Purchase Power And Fuel From External Customers 2,297 2,407
Revenues [4] 4,739 5,840
Operating Segments [Member] | Generation Mid Atlantic [Member]    
Segment Reporting Information [Line Items]    
Segment Reporting Information Revenue Net Of Purchase Power And Fuel From External Customers 832 808
Revenues [1],[4] 1,532 1,556
Operating Segments [Member] | Generation Midwest [Member]    
Segment Reporting Information [Line Items]    
Segment Reporting Information Revenue Net Of Purchase Power And Fuel From External Customers 715 709
Revenues [4] 1,089 1,276
Operating Segments [Member] | Generation New England [Member]    
Segment Reporting Information [Line Items]    
Segment Reporting Information Revenue Net Of Purchase Power And Fuel From External Customers 86 182
Revenues [4] 471 865
Operating Segments [Member] | Generation New York [Member]    
Segment Reporting Information [Line Items]    
Segment Reporting Information Revenue Net Of Purchase Power And Fuel From External Customers 141 169
Revenues [1],[4] 218 307
Operating Segments [Member] | Generation ERCOT [Member]    
Segment Reporting Information [Line Items]    
Segment Reporting Information Revenue Net Of Purchase Power And Fuel From External Customers 81 88
Revenues [4] 163 181
Operating Segments [Member] | Generation Other Regions [Member]    
Segment Reporting Information [Line Items]    
Segment Reporting Information Revenue Net Of Purchase Power And Fuel From External Customers 86 72
Revenues [2],[4] 222 212
Operating Segments [Member] | Generation All Other Segments [Member]    
Segment Reporting Information [Line Items]    
Segment Reporting Information Revenue Net Of Purchase Power And Fuel From External Customers 356 379
Operating Segments [Member] | Generation Reportable Segments Total [Member]    
Segment Reporting Information [Line Items]    
Segment Reporting Information Revenue Net Of Purchase Power And Fuel From External Customers 1,941 2,028
Revenues [4] $ 3,695 $ 4,397
[1] {F|ahBzfndlYmZpbGluZ3MtaHJkcmoLEgZYTUxEb2MiXlhCUkxEb2NHZW5JbmZvOmI4M2MxNDE3MDYxODRkNzQ5ZTcwNzJlZThlYmU3MWU2fFRleHRTZWxlY3Rpb246NjVBNzc5N0FGN0ZBMTJDMUQ2OThGQkE2NTU2Rjg4MUMM}
[2] {F|ahBzfndlYmZpbGluZ3MtaHJkcmoLEgZYTUxEb2MiXlhCUkxEb2NHZW5JbmZvOmI4M2MxNDE3MDYxODRkNzQ5ZTcwNzJlZThlYmU3MWU2fFRleHRTZWxlY3Rpb246N0VDOTc2NzhBOTQxRTVCRjVFQTBGQkE2NTU2RkQzMkMM}
[3] {F|ahBzfndlYmZpbGluZ3MtaHJkcmoLEgZYTUxEb2MiXlhCUkxEb2NHZW5JbmZvOmI4M2MxNDE3MDYxODRkNzQ5ZTcwNzJlZThlYmU3MWU2fFRleHRTZWxlY3Rpb246NUFDMUZBMUNBNUIxOEE4RTZBQjFGQkE2NTU2RjBBOEUM}
[4] {F|ahBzfndlYmZpbGluZ3MtaHJkcmoLEgZYTUxEb2MiXlhCUkxEb2NHZW5JbmZvOmI4M2MxNDE3MDYxODRkNzQ5ZTcwNzJlZThlYmU3MWU2fFRleHRTZWxlY3Rpb246NUMzQ0MzNUZBOUJFQjJEREJCRDZGQkE2NTU2RkRBMTEM}