Lease Commitments - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Leases Disclosure [Line Items]
Rental expense for operating leases	$ 47	$ 46	$ 41
Operating leases, future minimum payment, total	186
Operating leases, future minimum payment, 2019	42
Operating leases,future minimum payment, 2020	36
Operating leases, future minimum payment, 2021	29
Operating leases, future minimum payment, 2022	26
Operating leases, future minimum payment, 2023	20
Operating leases, future minimum payment, 2024 and thereafter	$ 33
Maximum
Leases Disclosure [Line Items]
Operating leases expiration date	2045