Segment Information We assess our business on a regional basis due to the impact on our financial performance of the differing characteristics of these regions, particularly with respect to competition, regulation and other factors impacting supply and demand. At March 31, 2014, our reportable segments were West (including geothermal), Texas, North (including Canada) and Southeast. We continue to evaluate the optimal manner in which we assess our performance including our segments and future changes may result. Commodity Margin is a key operational measure reviewed by our chief operating decision maker to assess the performance of our segments. During the fourth quarter of 2013, we changed the methodology previously used during 2013 for allocating corporate expenses to our segments. This change had no impact on our Consolidated Condensed Statements of Operations for the three months ended March 31, 2013; however, segment amounts previously reported for the three months ended March 31, 2013 were adjusted by immaterial amounts. Our segment data for the three months ended March 31, 2013 has been recast to reflect this change. The tables below show our financial data for our segments for the periods indicated (in millions). | | | | | | | | | | | | | | | | | | | | | | | | | | Three Months Ended March 31, 2014 | | West | | Texas | | North | | Southeast | | Consolidation and Elimination | | Total | Revenues from external customers | $ | 491 |
| | $ | 647 |
| | $ | 639 |
| | $ | 188 |
| | $ | — |
| | $ | 1,965 |
| Intersegment revenues | 2 |
| | 12 |
| | 15 |
| | 81 |
| | (110 | ) | | — |
| Total operating revenues | $ | 493 |
| | $ | 659 |
| | $ | 654 |
| | $ | 269 |
| | $ | (110 | ) | | $ | 1,965 |
| Commodity Margin | $ | 202 |
| | $ | 121 |
| | $ | 267 |
| | $ | 55 |
| | $ | — |
| | $ | 645 |
| Add: Unrealized mark-to-market commodity activity, net and other(1) | 29 |
| | (46 | ) | | (17 | ) | | 6 |
| | (9 | ) | | (37 | ) | Less: | | | | | | | | | | | | Plant operating expense | 105 |
| | 90 |
| | 52 |
| | 27 |
| | (9 | ) | | 265 |
| Depreciation and amortization expense | 60 |
| | 42 |
| | 33 |
| | 18 |
| | — |
| | 153 |
| Sales, general and other administrative expense | 10 |
| | 12 |
| | 6 |
| | 6 |
| | (1 | ) | | 33 |
| Other operating expenses | 12 |
| | 2 |
| | 6 |
| | 1 |
| | 1 |
| | 22 |
| (Income) from unconsolidated investments in power plants | — |
| | — |
| | (9 | ) | | — |
| | — |
| | (9 | ) | Income (loss) from operations | 44 |
| | (71 | ) | | 162 |
| | 9 |
| | — |
| | 144 |
| Interest expense, net of interest income | | | | | | | | | | | 165 |
| Other (income) expense, net | | | | | | | | | | | 11 |
| Loss before income taxes | | | | | | | | | | | $ | (32 | ) |
| | | | | | | | | | | | | | | | | | | | | | | | | | Three Months Ended March 31, 2013 | | West | | Texas | | North | | Southeast | | Consolidation and Elimination | | Total | Revenues from external customers | $ | 383 |
| | $ | 407 |
| | $ | 306 |
| | $ | 145 |
| | $ | — |
| | $ | 1,241 |
| Intersegment revenues | 1 |
| | 7 |
| | 7 |
| | 33 |
| | (48 | ) | | — |
| Total operating revenues | $ | 384 |
| | $ | 414 |
| | $ | 313 |
| | $ | 178 |
| | $ | (48 | ) | | $ | 1,241 |
| Commodity Margin | $ | 202 |
| | $ | 76 |
| | $ | 142 |
| | $ | 41 |
| | $ | — |
| | $ | 461 |
| Add: Unrealized mark-to-market commodity activity, net and other(1) | (37 | ) | | (11 | ) | | 7 |
| | 7 |
| | (7 | ) | | (41 | ) | Less: | | | | | | | | | | | | Plant operating expense | 95 |
| | 65 |
| | 43 |
| | 31 |
| | (7 | ) | | 227 |
| Depreciation and amortization expense | 53 |
| | 42 |
| | 33 |
| | 19 |
| | (1 | ) | | 146 |
| Sales, general and other administrative expense | 7 |
| | 14 |
| | 6 |
| | 6 |
| | — |
| | 33 |
| Other operating expenses | 9 |
| | 1 |
| | 7 |
| | 1 |
| | — |
| | 18 |
| (Income) from unconsolidated investments in power plants | — |
| | — |
| | (8 | ) | | — |
| | — |
| | (8 | ) | Income (loss) from operations | 1 |
|
| (57 | ) |
| 68 |
|
| (9 | ) |
| 1 |
| | 4 |
| Interest expense, net of interest income | | | | | | | | | | | 174 |
| Other (income) expense, net | | | | | | | | | | | 5 |
| Loss before income taxes | | | | | | | | | | | $ | (175 | ) |
_________ | | (1) | Includes $(29) million and $(16) million of lease levelization and $4 million and $4 million of amortization expense for the three months ended March 31, 2014 and 2013, respectively. |
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