Equity (Schedule of redeemable noncontrolling interest) (Details) $ in Millions	3 Months Ended
Mar. 31, 2016 USD ($)
Increase (Decrease) in Temporary Equity [Roll Forward]
Balance as of December 31, 2015	$ 920
Net income attributable to noncontrolling interest	26
Distributions payable to noncontrolling interest	(22)
Redemption value adjustment	(4)
Balance as of March 31, 2016	$ 920

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

No definition available.

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- Definition

Change in noncontrolling interest during the period as a result of a change in the redemption value of redeemable noncontrolling interest.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 480
-SubTopic 10
-Section S99
-Paragraph 3A
-Subparagraph 15
-URI http://asc.fasb.org/extlink&oid=65877616&loc=SL6540498-122764

Reference 2: http://www.xbrl.org/2003/role/presentationRef
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-Section S99
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-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

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-URI http://asc.fasb.org/extlink&oid=65877616&loc=SL6540498-122764

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- Definition

Decrease in noncontrolling interest balance from payment of dividends or other distributions by the non-wholly owned subsidiary or partially owned entity, included in the consolidation of the parent entity, to the noncontrolling interest holders.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

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- Definition

Amount of Net Income (Loss) attributable to redeemable noncontrolling interest.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.19)
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- Definition

As of the reporting date, the aggregate carrying amount of all noncontrolling interests which are redeemable by the (parent) entity (1) at a fixed or determinable price on a fixed or determinable date, (2) at the option of the holder of the noncontrolling interest, or (3) upon occurrence of an event that is not solely within the control of the (parent) entity. This item includes noncontrolling interest holder's ownership (or holders' ownership) regardless of the type of equity interest (common, preferred, other) including all potential organizational (legal) forms of the investee entity.

+ References

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