Leasing - Schedule of Aggregate Right-of Use Assets and Related Lease Obligations (Detail) - USD ($) $ in Millions	Mar. 31, 2019	Jan. 01, 2019
Leases [Abstract]
Operating lease right-of-use assets	$ 185	$ 201
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:PropertyPlantAndEquipmentNet
Other current liabilities	$ 66
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilitiesCurrent
Other noncurrent liabilities and deferred credits	$ 119
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	us-gaap:DeferredCreditsAndOtherLiabilitiesNoncurrent
Total operating lease liabilities	$ 185	$ 201