Supplemental Cash Flow Information - Reconciliation of Additions to Property, Plant and Equipment to Total Capital Expenditures (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013
Supplemental Cash Flow Elements [Abstract]
Additions to property, plant and equipment per consolidated statements of cash flows					$ 952		$ 733
Non-cash additions to property, plant and equipment					4		0
Acquisitions					2,714	[1]	1,386	[1]
Asset retirement expenditures					1		0
Increase in capital accruals					0		63
Total capital expenditures	$ 3,101	[2],[3]	$ 336	[2],[3]	$ 3,671	[2],[3]	$ 2,182	[2],[3]

[1] The 2014 acquisition includes the acquisition of Hess' Retail Operations and Related Assets. The 2013 acquisition includes the acquisition of the Galveston Bay Refinery and Related Assets. The acquisition numbers above include property, plant and equipment and intangibles. See Note 4.

[2] See Note 18 for a reconciliation of total capital expenditures to additions to property, plant and equipment as reported in the consolidated statements of cash flows.

[3] Capital expenditures include changes in capital accruals and acquisitions.