Leases - Operating Leases Information (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Leases [Abstract]
Cash paid for amounts included in the measurement of operating lease liabilities	$ 28	$ 27	$ 56	$ 53
Right-of-use assets obtained in exchange for new operating lease liabilities	$ 2	$ 11	$ 6	$ 20
Weighted-average remaining lease term (years)	5 years 7 months 6 days	6 years 6 months	5 years 7 months 6 days	6 years 6 months
Weighted-average discount rate applied to operating leases (percent)	3.60%	3.60%	3.60%	3.60%