Financial Instruments and Fair Value Measurements (Equity Method Investment, Summarized Financial Information, Profit (Loss)) (Details) - Digicert Parent, Inc. - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Schedule of Equity Method Investments [Line Items]
Revenue	$ 121	$ 80	$ 230	$ 220
Gross profit	104	67	194	181
Net loss	$ (18)	$ (83)	$ (55)	$ (288)

The amount of gross profit (loss) reported by an equity method investment of the entity.

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The amount of net income (loss) reported by an equity method investment of the entity.

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Amount of revenue from sale of product and rendering of service reported by equity method investee.

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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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