Lease Obligations - Summary of Leased Assets and Lease Liability Obligations (Detail) - USD ($) $ in Millions		Mar. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Operating lease assets		$ 330	$ 349
Finance lease assets	[1]	$ 50	$ 50
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]		us-gaap:PropertyPlantAndEquipmentNet	us-gaap:PropertyPlantAndEquipmentNet
Total leased assets		$ 380	$ 399
Operating lease liabilities, Current		93	93
Finance lease liabilities, Current		45	47
Current lease obligations		138	140
Operating lease liabilities, Noncurrent		279	294
Total lease obligations		$ 417	$ 434

[1] As a result of the debt compliance matters, we determined that the classification of our finance lease obligations was current and, accordingly, we recorded those obligations within Current Liabilities on the Balance Sheets as of March 31, 2020 and December 31, 2019.