Other Liabilities - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Other Liabilities Disclosure [Abstract]
Operating lease costs	$ 116	$ 132	$ 339	$ 374