Lease Obligations - Summary of Leased Assets and Lease Liability Obligations (Detail) - USD ($) $ in Millions		Dec. 31, 2019	Dec. 31, 2018
Leases [Abstract]
Operating lease assets		$ 364
Finance lease assets		$ 50	$ 70
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]		us-gaap:PropertyPlantAndEquipmentNet	us-gaap:PropertyPlantAndEquipmentNet
Total leased assets		$ 414	$ 70
Operating liabilities, Current		98
Finance liabilities, Current	[1]	47	8
Lease liabilities, Current		145	8
Operating liabilities, Noncurrent		304
Finance liabilities, Noncurrent			66
Lease liabilities, Noncurrent		304	66
Total lease liabilities		$ 449	$ 74

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