Other Items (Net Interest And Other Financial Income (Costs)) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015		Dec. 31, 2014	Dec. 31, 2013	Dec. 04, 2015
Interest income	$ 6		$ 7	$ 9
Interest expense	(325)		(229)	(195)
Interest capitalized	37		27	28
Loss on extinguishment of debt	(5)	[1]	0	0
Other financial costs	(31)		(21)	(21)
Net interest and other financial income (costs)	$ (318)		$ (216)	$ (179)
MarkWest
Transaction costs					$ 6

[1] 2015 includes $6 million of transaction costs related to the MarkWest Merger.