Debt - Summary of Outstanding Debt (Details) - Long-Term Debt - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Outstanding Principal Amount	$ 845	$ 500
Unamortized Debt Issuance Costs	(14)	(9)
Carrying Value	831	491
2025 Senior Notes
Debt Instrument [Line Items]
Outstanding Principal Amount	500	500
Unamortized Debt Issuance Costs	(8)	(9)
Carrying Value	492	$ 491
2026 Senior Notes
Debt Instrument [Line Items]
Outstanding Principal Amount	345
Unamortized Debt Issuance Costs	(6)
Carrying Value	$ 339

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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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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Amount, before accumulated amortization, of debt issuance costs classified as noncurrent. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

+ References

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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.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
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