Leasing - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019	Jan. 01, 2019
Leases [Line Items]
Operating lease right-of-use assets	$ 158	$ 158	$ 201
Operating lease, liability	158	158	$ 201
Costs from operating leases	21	60
Short-term rental expense		4
Variable lease payments	4	12
New lease cost	$ 4	$ 11
Minimum [Member]
Leases [Line Items]
Remaining lease term		1 year
Maximum [Member]
Leases [Line Items]
Remaining lease term		38 years