Summary of Significant Accounting Policies - Investments (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Schedule of Equity Method Investments [Line Items]
Other investments	$ 2	$ 2
Cleopatra
Schedule of Equity Method Investments [Line Items]
Ownership	1.00%	1.00%
Other investments	$ 2	$ 2
Economic Interest \| General Partner SPLC
Schedule of Equity Method Investments [Line Items]
Noncontrolling interest	2.00%

Equity Securities Without Readily Determinable Fair Value Percent

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- Definition

Amount of investment in equity security without readily determinable fair value.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 321
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=120269885&loc=SL75117539-209714

+ Details

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- Definition

The equity interest of noncontrolling shareholders, partners or other equity holders in consolidated entity.

+ References

No definition available.

+ Details

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- Definition

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.

+ Details

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