Carrying amount as of the balance sheet date, which is the cumulative amount paid and (if applicable) the fair value of any noncontrolling interest in the acquiree, adjusted for any amortization recognized prior to the adoption of any changes in generally accepted accounting principles (as applicable) and for any impairment charges, in excess of the fair value of net assets acquired in one or more business combination transactions.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 142

-Paragraph 45

-Subparagraph e

-Clause 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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=14024403&loc=d3e13816-109267

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

-Publisher FASB

-Name Accounting Standards Codification

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141R

-Paragraph 34

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 142

-Paragraph 43

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 7: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 142

-Paragraph 45

-Subparagraph e

-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 8: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141R

-Paragraph 72

-Subparagraph d

-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

- Definition

The aggregate amount of goodwill acquired in the period and allocated to the reportable segment. The value is stated at fair value based on the purchase price allocation.

+ References+ Details

- Definition

Change in the carrying value of goodwill. The change could be the result of new goodwill acquired, goodwill impairment, if any, goodwill written off related to the sale of a business or other adjustments to goodwill.

+ References+ Details

Goodwill and Other Intangible Assets (Goodwill Narrative) (Details) (USD $)	3 Months Ended	12 Months Ended
	Jun. 30, 2012	Dec. 31, 2012	Dec. 31, 2011
Goodwill [Line Items]
Goodwill		$ 27,304,000,000	$ 27,230,000,000
Acquisitions		0	6,000,000
Goodwill balance increase (decrease)		74,000,000	278,000,000
Discount rates used in our reporting unit valuations minimum rate		11.00%
Discount rates used in our reporting unit valuations maximum rate		12.75%
Carrying amount exceeded the fair value of Real Estate	1,800,000,000
Currency Exchange Effect On Goodwill [Member]
Goodwill [Line Items]
Goodwill balance increase (decrease)		180,000,000	89,000,000
Disposition Effect Goodwill [Member]
Goodwill [Line Items]
Goodwill balance increase (decrease)		107,000,000	216,000,000
Real Estate Equity Properties And Investments [Member]
Goodwill [Line Items]
Carrying amount exceeded the fair value of Real Estate		2,600,000,000
Commercial Real Estate Portfolio Segment [Member]
Goodwill [Line Items]
Goodwill		926,000,000
Discount Rate Derived By Capital Asset Pricing Model	11.00%
Amount Carrying Value Exceeds Estimated Fair Value	$ 1,700,000,000