Net Interest And Other Financial Costs (Detail) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Other Income and Expenses [Abstract]
Interest income		$ (9)	$ (25)	$ (18)	$ (45)
Interest expense		350	229	690	442
Interest capitalized		(35)	(16)	(67)	(34)
Pension and other postretirement non-service costs	[1]	3	2	0	2
Loss on extinguishment of debt		0	0	0	4
Other financial costs		13	5	23	9
Net interest and other financial costs		$ 322	$ 195	$ 628	$ 378

[1] See Note 21.