v2.4.0.6

Segment and Significant Customer Information (Details) (USD $) In Millions, unless otherwise specified | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2012 | Sep. 30, 2011 | Sep. 30, 2012 | Sep. 30, 2011
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |
Revenues from external customers | $ 1,996 |  | $ 2,209 |  | $ 4,111 |  | $ 5,341 |
Intersegment revenues | 0 |  | 0 |  | 0 |  | 0 |
Total operating revenues | 1,996 |  | 2,209 |  | 4,111 |  | 5,341 |
Commodity Margin | 897 |  | 825 |  | 2,023 |  | 1,921 |
Add: Mark-to-market commodity activity, net and other | 202 | [1],[2] | (20) | [1],[2] | (58) | [1],[3] | (57) | [1],[3]
Plant operating expense | 207 |  | 212 |  | 699 |  | 711 |
Depreciation and amortization expense | 140 |  | 143 |  | 418 |  | 405 |
Sales, general and other administrative expense | 36 |  | 33 |  | 104 |  | 99 |
Other operating expenses | 18 | [4] | 19 | [4] | 58 | [4] | 57 | [4]
(Income) loss from unconsolidated investments in power plants | (7) |  | (5) |  | (21) |  | (12) |
Income (loss) from operations | 705 |  | 403 |  | 707 |  | 604 |
Interest expense, net of interest income | 181 |  | 190 |  | 545 |  | 568 |
Loss on interest rate derivatives | 0 |  | 3 |  | 14 |  | 149 |
Debt Extinguishment Costs and Other (Income) Expense, Net | 6 |  | 0 |  | 26 |  | 108 |
Income (loss) before income taxes and discontinued operations | 518 |  | 210 |  | 122 |  | (221) |
Lease levelization | 16 |  | 11 |  | 7 |  | 15 |
Contract amortization | 4 |  | 4 |  | 11 |  | 5 |
RGGI Compliance and Other Environmental Costs | 4 |  | 3 |  | 9 |  | 7 |
Commodity Margin Riverside Energy Center | 32 |  | 31 |  | 64 |  | 62 |
West [Member] |  |  |  |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |
Revenues from external customers | 509 |  | 688 |  | 1,183 |  | 1,753 |
Intersegment revenues | 2 |  | 3 |  | 7 |  | 7 |
Total operating revenues | 511 |  | 691 |  | 1,190 |  | 1,760 |
Commodity Margin | 330 |  | 329 |  | 748 |  | 798 |
Add: Mark-to-market commodity activity, net and other | (40) | [1],[2] | 20 | [1],[2] | (80) | [1],[3] | 36 | [1],[3]
Plant operating expense | 88 |  | 94 |  | 281 |  | 297 |
Depreciation and amortization expense | 52 |  | 52 |  | 151 |  | 140 |
Sales, general and other administrative expense | 9 |  | 10 |  | 23 |  | 29 |
Other operating expenses | 10 | [4] | 11 | [4] | 30 | [4] | 30 | [4]
(Income) loss from unconsolidated investments in power plants | 0 |  | 0 |  | 0 |  | 0 |
Income (loss) from operations | 131 |  | 182 |  | 183 |  | 338 |
Texas [Member] |  |  |  |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |
Revenues from external customers | 886 |  | 843 |  | 1,430 |  | 1,939 |
Intersegment revenues | (34) |  | 3 |  | 27 |  | 13 |
Total operating revenues | 852 |  | 846 |  | 1,457 |  | 1,952 |
Commodity Margin | 218 |  | 162 |  | 472 |  | 357 |
Add: Mark-to-market commodity activity, net and other | 249 | [1],[2] | (21) | [1],[2] | 66 | [1],[3] | (54) | [1],[3]
Plant operating expense | 49 |  | 50 |  | 189 |  | 193 |
Depreciation and amortization expense | 35 |  | 34 |  | 104 |  | 99 |
Sales, general and other administrative expense | 12 |  | 10 |  | 36 |  | 33 |
Other operating expenses | 1 | [4] | (1) | [4] | 4 | [4] | 2 | [4]
(Income) loss from unconsolidated investments in power plants | 0 |  | 0 |  | 0 |  | 0 |
Income (loss) from operations | 370 |  | 48 |  | 205 |  | (24) |
North [Member] |  |  |  |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |
Revenues from external customers | 407 |  | 430 |  | 974 |  | 1,025 |
Intersegment revenues | 4 |  | (8) |  | 9 |  | 5 |
Total operating revenues | 411 |  | 422 |  | 983 |  | 1,030 |
Commodity Margin | 266 | [5] | 259 | [5] | 591 | [5] | 578 | [5]
Add: Mark-to-market commodity activity, net and other | (26) | [1],[2] | (11) | [1],[2] | (17) | [1],[3] | (12) | [1],[3]
Plant operating expense | 51 |  | 44 |  | 154 |  | 136 |
Depreciation and amortization expense | 33 |  | 36 |  | 100 |  | 102 |
Sales, general and other administrative expense | 8 |  | 7 |  | 22 |  | 19 |
Other operating expenses | 6 | [4] | 7 | [4] | 21 | [4] | 23 | [4]
(Income) loss from unconsolidated investments in power plants | (7) |  | (5) |  | (21) |  | (12) |
Income (loss) from operations | 149 |  | 159 |  | 298 |  | 298 |
Southeast [Member] |  |  |  |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |
Revenues from external customers | 194 |  | 248 |  | 524 |  | 624 |
Intersegment revenues | 68 |  | 31 |  | 84 |  | 116 |
Total operating revenues | 262 |  | 279 |  | 608 |  | 740 |
Commodity Margin | 83 |  | 75 |  | 212 |  | 188 |
Add: Mark-to-market commodity activity, net and other | 27 | [1],[2] | 0 | [1],[2] | (5) | [1],[3] | (4) | [1],[3]
Plant operating expense | 29 |  | 33 |  | 98 |  | 107 |
Depreciation and amortization expense | 21 |  | 22 |  | 66 |  | 67 |
Sales, general and other administrative expense | 8 |  | 7 |  | 23 |  | 18 |
Other operating expenses | (1) | [4] | 0 | [4] | 2 | [4] | 3 | [4]
(Income) loss from unconsolidated investments in power plants | 0 |  | 0 |  | 0 |  | 0 |
Income (loss) from operations | 53 |  | 13 |  | 18 |  | (11) |
Consolidation and Elimination [Member] |  |  |  |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |
Revenues from external customers | 0 |  | 0 |  | 0 |  | 0 |
Intersegment revenues | (40) |  | (29) |  | (127) |  | (141) |
Total operating revenues | (40) |  | (29) |  | (127) |  | (141) |
Commodity Margin | 0 |  | 0 |  | 0 |  | 0 |
Add: Mark-to-market commodity activity, net and other | (8) | [1],[2] | (8) | [1],[2] | (22) | [1],[3] | (23) | [1],[3]
Plant operating expense | (10) |  | (9) |  | (23) |  | (22) |
Depreciation and amortization expense | (1) |  | (1) |  | (3) |  | (3) |
Sales, general and other administrative expense | (1) |  | (1) |  | 0 |  | 0 |
Other operating expenses | 2 | [4] | 2 | [4] | 1 | [4] | (1) | [4]
(Income) loss from unconsolidated investments in power plants | 0 |  | 0 |  | 0 |  | 0 |
Income (loss) from operations | $ 2 |  | $ 1 |  | $ 3 |  | $ 3 |
[1] | Mark-to-market commodity activity represents the change in the unrealized portion of our mark-to-market activity, net, included in operating revenues and fuel and purchased energy expense on our Consolidated Condensed Statements of Operations
[2] | Includes $16 million and $11 million of lease levelization for the three months ended September 30, 2012 and 2011, respectively, and $4 million of amortization expense for each of the three months ended September 30, 2012 and 2011.
[3] | Includes $7 million and $15 million of lease levelization and $11 million and $5 million of amortization expense for the nine months ended September 30, 2012 and 2011, respectively.
[4] | Excludes $4 million and $3 million of RGGI compliance and other environmental costs for the three months ended September 30, 2012 and 2011, respectively, and $9 million and $7 million for the nine months ended September 30, 2012 and 2011, respectively, which are components of Commodity Margin.
[5] | Our North segment includes Commodity Margin related to Riverside Energy Center, LLC of $32 million and $31 million for the three months ended September 30, 2012 and 2011, respectively, and $64 million and $62 million for the nine months ended September 30, 2012 and 2011, respectively.

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