Investments and Restricted Cash and Investments Equity Method Investments (Details) $ in Millions	9 Months Ended
Sep. 30, 2018 USD ($)
Accounting Standards Update 2016-15 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Prior Period Reclassification Adjustment	$ 26

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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