v3.8.0.1

Investments (Other Long Term Investments) (Details) - USD ($) $ in Millions		Dec. 31, 2017	Dec. 31, 2016
Other Long-Term Investments [Line Items]
Other long-term investments	[1]	$ 12,308	$ 11,283
Private equity
Other Long-Term Investments [Line Items]
Other long-term investments		4,280	4,059
Hedge funds
Other Long-Term Investments [Line Items]
Other long-term investments		3,222	2,660
Real estate-related
Other Long-Term Investments [Line Items]
Other long-term investments		1,218	1,291
Joint ventures and limited partnerships
Other Long-Term Investments [Line Items]
Other long-term investments		8,720	8,010
Wholly Owned Properties [Member]
Other Long-Term Investments [Line Items]
Other long-term investments		2,409	2,195
Other
Other Long-Term Investments [Line Items]
Other long-term investments		1,179	1,078
Mortgages | Senior Notes | Real estate-related
Other Long-Term Investments [Line Items]
Long-term Debt		$ 799	$ 659
[1] See Note 5 for details of balances associated with variable interest entities.

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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16))
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