v2.4.0.8

Summary of Significant Accounting Policies (Details) (USD $) In Millions, unless otherwise specified |  |  |  |  |  |  |  |  |  |  |  |  |  | 12 Months Ended
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Dec. 31, 2013 | Dec. 31, 2012 | Dec. 31, 2013 Freestone Energy Center [Member] | Dec. 31, 2013 Hidalgo Energy Center [Member] | Dec. 31, 2013 Debt Service | Dec. 31, 2012 Debt Service | Dec. 31, 2013 Rent Reserve [Member] | Dec. 31, 2012 Rent Reserve [Member] | Dec. 31, 2013 Construction Major Maintenance | Dec. 31, 2012 Construction Major Maintenance | Dec. 31, 2013 Security Project Insurance | Dec. 31, 2012 Security Project Insurance | Dec. 31, 2013 Other | Dec. 31, 2012 Other | Dec. 31, 2013 Greenfield [Member] | Dec. 31, 2013 Whitby [Member] | Dec. 31, 2012 Comprehensive Income [Member] | Dec. 31, 2011 Comprehensive Income [Member] | Dec. 31, 2012 Cash Flow Statement [Member] | Dec. 31, 2011 Cash Flow Statement [Member]
Restricted Cash and Cash Equivalents Items [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Prior Period Reclassification Adjustment |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ (6) | $ (14) | $ 5 | $ 0
Held-to-maturity Securities, Restricted | 24 | 25 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Current | 203 | 193 |  |  | 11 | [1] | 11 | [1] | 3 | 0 | 35 | 32 | 151 | 101 | 3 | 49 |  |  |  |  |  |
Non-current | 69 | 60 |  |  | 41 | [1] | 41 | [1] | 0 | 0 | 20 | 14 | 6 | 3 | 2 | 2 |  |  |  |  |  |
Total | 272 | 253 |  |  | 52 | [1] | 52 | [1] | 3 | 0 | 55 | 46 | 157 | 104 | 5 | 51 |  |  |  |  |  |
Prior Period Adjustment [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership percentage in equity method investment |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 50.00% | 50.00% |  |  |  |
Cash and cash equivalents subject to project finance facilities and lease agreements | 292 | 131 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Inventory | 364 | 301 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Property, plant and equipment, salvage value (as a percent) | 10.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Property, plant and equipment, salvage value of rotables (as a percent) | 0.15% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Asset retirement obligations | 44 | 38 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Jointly Owned Plants [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Jointly Owned Utility Plant, Proportionate Ownership Share |  |  | 75.00% | 78.50% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Jointly Owned Utility Plant, Gross Ownership Amount of Plant in Service |  |  | 393 | 255 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Jointly Owned Utility Plant, Ownership Amount of Plant Accumulated Depreciation |  |  | (135) | (93) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Jointly Owned Utility Plant, Ownership Amount of Construction Work in Progress |  |  | $ 0 | $ 0 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
[1] | At December 31, 2013 and 2012, amounts restricted for debt service included approximately $24 million and $25 million, respectively, of repurchase agreements with a financial institution containing maturity dates greater than one year.

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- Definition The carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 410 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Asset Retirement Obligation -URI http://asc.fasb.org/extlink&oid=6505190 + Details
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