Supplemental Cash Flow Information - Summary of Supplemental Cash Flow Information (Detail) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Net cash provided by operating activities included:
Interest paid (net of amounts capitalized)	$ 82	$ 86
Net income taxes paid to taxing authorities	299	719
Non-cash investing and financing activities:
Capital lease obligations increase	0	61
Property, plant and equipment sold	4	0
Property, plant and equipment acquired	4	0
Acquisition:
Contingent consideration	0	600	[1]
Payable to seller	$ 0	$ 6	[1]

[1] Acquisition-date fair value of non-cash consideration associated with the Galveston Bay Refinery and Related Assets acquisition.