Commitments, Contingencies and Other Items - Other Commitments (Details) - USD ($)	Jun. 30, 2019	Dec. 31, 2018
Loss Contingencies [Line Items]
Amount outstanding under letters of credit or other similar obligations	$ 27,000,000	$ 30,000,000
Collateralized by cash, that is reflected on the consolidated balance sheets as restricted cash	21,000,000	$ 24,000,000
Unfavorable Regulatory Action
Loss Contingencies [Line Items]
Estimate of possible loss	$ 100,000

The value of the collateral (typically cash) that the entity receives in a financing transaction in exchange for securities lent. This item represents a liability in the financial statements of the lender of the securities.

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The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

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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.

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Reflects the estimated amount of loss from the specified contingency as of the balance sheet date.

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