Fair Value Instruments - Convertible Debt (Details) - 1.250 Convertible Senior Notes due 2025 - Convertible Debt - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Equity component	$ 361	$ 403
Principal amount	2,221	2,300
Unamortized debt discount	(289)	(355)
Net carrying amount	$ 1,932	$ 1,945

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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- Definition

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

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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

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Amount of unamortized debt discount (premium) and debt issuance costs.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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