Acquisitions and Investments (Acquisition of Refinery and Related Logistics and Marketing Assets) (Detail) (USD $)	6 Months Ended		1 Months Ended			3 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Feb. 01, 2013 Galveston Bay Refinery and Related Assets site Pipeline Terminal BPCD BPD MW	Jun. 30, 2014 Galveston Bay Refinery and Related Assets	Dec. 31, 2013 Galveston Bay Refinery and Related Assets	Sep. 30, 2014 Galveston Bay Refinery and Related Assets Subsequent Event
Business Acquisition [Line Items]
Refinery capacity (in barrels per calendar day)			451,000
Intrastate natural gas liquid pipelines (in number of pipelines)			3
Number of light product terminals (in number of terminals)			4
Number of branded sites (in number of sites)			1,200
Electric cogeneration capacity, megawatt			1,040
Allocation of space on Colonial Pipeline (in barrels per day)			50,000
Cash paid for acquisition	$ 42,000,000	$ 1,515,000,000	$ 1,490,000,000			$ 180,000,000
Inventories					935,000,000
Total cumulative payment capped over six-year period			$ 700,000,000	$ 700,000,000
Term of payment of maximum earnout provision payable to the company, years			6 years