Summary of Significant Accounting Policies - Summary of Financial Information for Joint Ventures (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Equity Method Investments and Joint Ventures [Abstract]
Total assets	$ 2,261	$ 1,924
Total liabilities	1,727	1,451
Revenues	804	731	$ 731
Net income	$ 106	$ 114	$ 261