This element represents the aggregate cost of investments accounted for under the equity method of accounting.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 12

-Article 5

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This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment losses recognized.

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- Definition

Total of all Stockholders' Equity (deficit) items, net of receivables from officers, directors owners, and affiliates of the entity which is directly or indirectly attributable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 27

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 20

-Article 7

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Accounting Research Bulletin (ARB)

-Number 51

-Paragraph 26

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Accounting Research Bulletin (ARB)

-Number 51

-Paragraph 38

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Accounting Research Bulletin (ARB)

-Number 51

-Paragraph A3

-Appendix A

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- Definition

The cash outflow associated with other investments held by the entity for investment purposes not otherwise defined in the taxonomy.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 15

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- Definition

The carrying amount of the variable interest entity's assets consolidated into the statement of financial position. In general, a VIE is a corporation, partnership, trust, or any other legal structure used for business purposes that either (a) does not have equity investors with voting rights or (b) has equity investors that do not provide sufficient financial resources for the entity to support its activities. A VIE often holds financial assets, including loans or receivables, real estate or other property. A VIE may be essentially passive or it may engage in research and development or other activities on behalf of another company.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name FASB Interpretation (FIN)

-Number 46R

-Paragraph 26

-Subparagraph b

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number FAS140-4 and FIN46(R)-8

-Paragraph 9

-Subparagraph c(5), c(6)

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-Publisher FASB

-Name FASB Interpretation (FIN)

-Number 46R

-Paragraph 23

-Subparagraph a

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-Publisher FASB

-Name FASB Staff Position (FSP)

-Number FAS140-4 and FIN46(R)-8

-Paragraph C5

-Subparagraph a

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name FASB Interpretation (FIN)

-Number 46R

-Paragraph 23

-Subparagraph b

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name FASB Interpretation (FIN)

-Number 46R

-Paragraph 24

-Subparagraph b

Reference 7: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number FAS140-4 and FIN46(R)-8

-Paragraph C8

-Subparagraph b

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- Definition

Percentage of the VIE's voting interest owned by the registrant. In general, a VIE is a corporation, partnership, trust, or any other legal structure used for business purposes that either (a) does not have equity investors with voting rights or (b) has equity investors that do not provide sufficient financial resources for the entity to support its activities. A VIE often holds financial assets, including loans or receivables, real estate or other property. A VIE may be essentially passive or it may engage in research and development or other activities on behalf of another company.

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- Definition

Describes the terms of arrangements, giving consideration to both explicit arrangements and implicit variable interests, that could require the enterprise to provide financial support (for example, liquidity arrangements and obligations to purchase assets) to the VIE, including events or circumstances that could expose the enterprise to a loss.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number FAS140-4 and FIN46(R)-8

-Paragraph 9

-Subparagraph C(4)

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-Publisher FASB

-Name FASB Staff Position (FSP)

-Number FAS140-4 and FIN46(R)-8

-Paragraph C5

-Subparagraph c

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- Definition

Carrying Value of Restricted Trust Funds and Escrow Accounts for Which the Company is Not the Sole Beneficiary Specifically for Future Settlement of Landfill and Environmental Remediation Liabilities.

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- Definition

Equity Method Investment Non Cash Component.

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- Definition

Equity method investments debt balance.

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- Definition

Variable Interest Entities.

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- Definition

Variable Interest Entities.

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Variable Interest Entity, Noncontrolling Interest in Consolidated Net Income.

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Variable Interest Entity, Reporting Entity Percentage of Interest in Earnings After Achieving Targeted Returns.

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Variable Interest Entity, Third Parties' Percentage of Interest in Earnings After Achieving Targeted Returns.

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Variable Interest Entity, Third Party Initial Investment.

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Variable Interest Entity, Third Party Ownership Percentage of Company One.

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Variable Interest Entities (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended			9 Months Ended			9 Months Ended	1 Months Ended		1 Months Ended	9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010	Dec. 31, 2010	Sep. 30, 2011 Limited Liability Company II [Member]	Sep. 30, 2011 Limited Liability Company II [Member] Limited Liability Company I [Member]	Dec. 31, 2000 Limited Liability Company II [Member] Limited Liability Company I [Member]	Sep. 30, 2011 Limited Liability Company I [Member]	Apr. 30, 2010 Low-Income Housing Properties [Member]	Sep. 30, 2011 Low-Income Housing Properties [Member]	Jan. 30, 2011 Investment in Refined Coal Facility [Member]	Sep. 30, 2011 Investment in Refined Coal Facility [Member]
Variable Interest Entities (Textual) [Abstract]
Percentage of ownership in LLC's						0.25%			0.50%
Percentage of variable interest entities owned by other companies						99.75%			99.50%
Reporting entity percentage of interest in earnings of variable interest entity after achieving targeted returns							80.00%
Other companies percentage of interest in earnings of variable interest entity after achieving targeted returns							20.00%
Noncontrolling interests	$ 337		$ 337		$ 331		$ 248
Value of notes payable included in consideration for investment										215
Cash payments to acquire equity method investment										6		48	48
Investment balance											184		42
Equity method investments debt balance											181
Consolidated variable interest entity carrying amount of asset							310
Total initial investment by other companies								167
Consideration for investment										221
Variable Interest Entities (Additional Details) [Abstract]
Expense recognized for other companies' noncontrolling interests in LLCs earnings	13	13	38	38
Carrying value of restricted trust funds and escrow accounts for which company is the not sole beneficiary specifically for future settlement of landfill and environmental remediation liabilities	$ 108		$ 108
Under the LLC agreements, the LLC shall be dissolved upon the occurrence of any of the following events			(i)A written decision of all members of the LLCs; (ii) December31, 2063; (iii) a court's dissolution of the LLCs; or (iv) the LLCs ceasing to own any interest in the waste-to-energy facilities.