Debt (Convertible Debenture Terms) (Details) $ / shares in Units, $ in Millions	12 Months Ended
Dec. 31, 2019 USD ($) $ / shares
Debt Disclosure [Abstract]
Outstanding principal amount	$ 215
Unamortized debt discount	68
Net debt carrying amount	145
Equity Component carrying amount	$ 78
Conversion rate (shares of common stock per $1,000 of principal amount)	13.9500
Effective conversion price (per $1,000 of principal amount) per share \| $ / shares	$ 71.6843

Carrying amount of long-term convertible debt as of the balance sheet date, net of the amount due in the next twelve months or greater than the normal operating cycle, if longer. The debt is convertible into another form of financial instrument, typically the entity's common stock.

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-SubTopic 10
-Section S99
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No definition available.

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The carrying amount of the equity component of convertible debt which may be settled in cash upon conversion.

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The price per share of the conversion feature embedded in the debt instrument.

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Ratio applied to the conversion of debt instrument into equity with equity shares divided by debt principal amount.

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Face (par) amount of debt instrument at time of issuance.

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Amount, after accumulated amortization, of debt discount.

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