General (Details)	6 Months Ended
Jun. 30, 2013 OwnedAndOperatedCompanies OperatingSegments
Other Ownership Interests [Line Items]
Number of operating segments	9
Number of owned and operated electric utility companies in the Western United States	1
Number of owned and operated electric and natural gas utility companies in the Midwestern United States	1
Number of owned and operated interstate natural gas pipeline companies in the United States	2
Number of owned and operated electricity distribution companies in Great Britain	2
Number of owned and operated eal estate brokerage firms in the United States	1
Number of owned and operated real estate franchise networks in the united states	1
Ownership interest in electric transmission businesses, ownership percentage	50.00%
Electric Transmission Texas, LLC [Member]
Other Ownership Interests [Line Items]
Equity method investment, ownership percentage	50.00%
Electric Transmission America, LLC [Member]
Other Ownership Interests [Line Items]
Equity method investment, ownership percentage	50.00%

Number of owned and operated electric and natural gas utility companies in the Midwestern United States.

No definition available.

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- Definition

Number of owned and operated electricity distribution companies in Great Britain.

+ References

No definition available.

+ Details

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- Definition

Number of owned and operated electric utility companies in the Western United States.

+ References

No definition available.

+ Details

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- Definition

Number of owned and operated interstate natural gas pipeline companies in the United States.

+ References

No definition available.

+ Details

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- Definition

Represents the number of owned and operated real estate franchise networks In the United States.

+ References

No definition available.

+ Details

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- Definition

Number of owned and operated residential real estate brokerage firms in the United States.

+ References

No definition available.

+ Details

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- Definition

The Ownership interest percentage in electric transmission businesses.

+ References

No definition available.

+ Details

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- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 159

-Paragraph 18

-Subparagraph f

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 323

-SubTopic 10

-Section 50

-Paragraph 3

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=6382943&loc=d3e33918-111571

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

-Publisher AICPA

-Name Accounting Principles Board Opinion (APB)

-Number 18

-Paragraph 20

-Subparagraph a (1)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

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- Definition

Number of operating segments. An operating segment is a component of an enterprise: (a) that engages in business activities from which it may earn revenues and incur expenses (including revenues and expenses relating to transactions with other components of the same enterprise), (b) whose operating results are regularly reviewed by the enterprise's chief operating decision maker to make decisions about resources to be allocated to the segment and assess its performance, and (c) for which discrete financial information is available. An operating segment may engage in business activities for which it has yet to earn revenues, for example, start-up operations may be operating segments before earning revenues.

+ References

No definition available.

+ Details

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- Details

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