The amount of expense provided in the period for legal costs incurred on or before the balance sheet date pertaining to resolved, pending or threatened litigation, including arbitration and mediation proceedings.

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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.

+ References

No definition available.

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- Definition

Amount of damages awarded to the plaintiff in the legal matter.

+ References

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

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-Topic 460
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Contingent Liabilities (Narrative) (Details) - USD ($) $ in Millions		3 Months Ended
	Jan. 17, 2014	Mar. 31, 2019	Mar. 31, 2018
Loss Contingencies [Line Items]
Legal fees		$ 1	$ 3
Pending Litigation \| Minimum
Loss Contingencies [Line Items]
Loss contingency, estimate of possible loss		0
Pending Litigation \| Maximum
Loss Contingencies [Line Items]
Loss contingency, estimate of possible loss		$ 34
Butte Local Development v. Masters Group v. Comerica Bank
Loss Contingencies [Line Items]
Amount of damages awarded by the jury	$ 52