Leases - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Lessee Lease Description [Line Items]
Operating lease weighted average remaining term	3 years
Finance lease weighted average remaining term	5 years
Operating lease weighted-average discount rates	6.50%
Finance lease weighted-average discount rates	5.60%
Impairment of operating right-of-use assets	$ 2
Rental expense			$ 48
Total future lease commitments	46
Series of Individually Immaterial Business Acquisitions [Member]
Lessee Lease Description [Line Items]
Rental expense	2	$ 2	$ 3
Total future lease commitments	$ 4
Operating leases, expiry year	2023