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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