Overview - Narrative (Details) $ in Millions	Sep. 30, 2017 USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Variable interest entity, assets	$ 8,110
Variable interest entity, assets related to real estate held for investment	7,680
Variable interest entity, liabilities	4,330
Variable interest entity, equity	3,790
Variable interest entity, equity, portion attributable to noncontrolling interest	$ 1,350

Variable Interest Entity, Consolidated, Carrying Amount, Assets, Real Estate Held for Investment

No definition available.

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- Definition

Variable Interest Entity, Consolidated, Carrying Amount, Equity

+ References

No definition available.

+ Details

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Period Type:	instant

- Definition

Variable Interest Entity, Consolidated, Carrying Amount, Equity, Portion Attributable to Noncontrolling Interest

+ References

No definition available.

+ Details

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Namespace Prefix:	nysedei_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- References

No definition available.

+ Details

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- Definition

The carrying amount of the consolidated Variable Interest Entity's assets included in the reporting entity's statement of financial position.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (bb)
-URI http://asc.fasb.org/extlink&oid=77990344&loc=d3e5710-111685

+ Details

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Balance Type:	debit
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- Definition

The carrying amount of the consolidated Variable Interest Entity's liabilities included in the reporting entity's statement of financial position.

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
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