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Summary of Significant Accounting Policies - Additional Information (Detail) $ / shares in Units, $ in Millions		1 Months Ended	3 Months Ended
	Feb. 28, 2020 $ / shares shares	Dec. 31, 2020 shares	Dec. 31, 2020 USD ($) shares	Sep. 30, 2020 shares	Jun. 05, 2020 shares
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Capital stock authorized (in shares)	2,100,000,000
Preferred stock authorized (in shares)	100,000,000
Preferred stock par value (in dollars per share) | $ / shares	$ 1.00
Stock split, conversion ratio	477,242.614671815
Preferred stock outstanding (in shares)		0	0		0
Stock-based compensation expense | $			$ 6
Restricted Stock Units (RSUs)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Shares issued under Omnibus Incentive Plan (in shares)			30,914
Restricted Stock Units (RSUs) | Omnibus Incentive Plan
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Shares issued under Omnibus Incentive Plan (in shares)			2,553
Class A Common Stock
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Common stock authorized (in shares)	1,000,000,000	1,000,000,000	1,000,000,000	1,000,000,000
Common stock outstanding (in shares)		111,167,356	111,167,356	88,578,361
Shares issued in period (in shares)		22,586,442	4,321,259
Class A Common Stock | Omnibus Incentive Plan
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Common stock available for issuance (in shares)		31,169,099	31,169,099
Incentive plan period			10 years
Class A Common Stock | IPO
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Common stock outstanding (in shares)		88,550,000	88,550,000		88,550,000
Class A Common Stock | IPO | Omnibus Incentive Plan
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Common stock available for issuance (in shares)		1,000,000	1,000,000
Class B Common Stock
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Common stock authorized (in shares)	1,000,000,000	1,000,000,000	1,000,000,000	1,000,000,000
Common stock outstanding (in shares)	510,000,000	403,184,814	403,184,814	421,450,000
Exchange of LLC Units for Class B shares (in shares)			18,265,813
Class B Common Stock | IPO
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Common stock outstanding (in shares)		421,450,000	421,450,000		421,450,000

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