Intangible Assets - Finite-lived Intangible Assets (Detail) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets - Remaining Weighted-Average Estimated Useful Life	7 years	7 years 9 months 18 days
Finite-lived intangible assets - Gross Carrying Amount	$ 976	$ 976
Finite-lived intangible assets - Accumulated Amortization	291	185
Finite-lived intangible assets - Net Carrying Amount	$ 685	$ 791
Management Contracts [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets - Remaining Weighted-Average Estimated Useful Life	4 years	4 years 9 months 18 days
Finite-lived intangible assets - Gross Carrying Amount	$ 283	$ 283
Finite-lived intangible assets - Accumulated Amortization	172	135
Finite-lived intangible assets - Net Carrying Amount	$ 111	$ 148
Investor/Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets - Remaining Weighted-Average Estimated Useful Life	8 years 2 months 12 days	9 years 2 months 12 days
Finite-lived intangible assets - Gross Carrying Amount	$ 476	$ 476
Finite-lived intangible assets - Accumulated Amortization	88	39
Finite-lived intangible assets - Net Carrying Amount	$ 388	$ 437
Technology-Related [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets - Remaining Weighted-Average Estimated Useful Life	6 years 4 months 24 days	7 years 4 months 24 days
Finite-lived intangible assets - Gross Carrying Amount	$ 203	$ 203
Finite-lived intangible assets - Accumulated Amortization	25	9
Finite-lived intangible assets - Net Carrying Amount	$ 178	$ 194
Trade Names / Trademarks [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets - Remaining Weighted-Average Estimated Useful Life	2 years 3 months 18 days	3 years 3 months 18 days
Finite-lived intangible assets - Gross Carrying Amount	$ 14	$ 14
Finite-lived intangible assets - Accumulated Amortization	6	2
Finite-lived intangible assets - Net Carrying Amount	$ 8	$ 12

Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275

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- Definition

Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 928
-SubTopic 340
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6473545&loc=d3e61844-108004

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
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-Section 50
-Paragraph 2
-Subparagraph (a)(1)
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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.

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Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 926
-SubTopic 20
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=120154696&loc=d3e54445-107959

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-URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275

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- Definition

Remaining amortization period of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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