Related Party Transactions (Narrative) (Detail) (USD $)	12 Months Ended				3 Months Ended	12 Months Ended								12 Months Ended		0 Months Ended	12 Months Ended			1 Months Ended	12 Months Ended			1 Months Ended			12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Jun. 30, 2011	Mar. 31, 2012 Centennial [Member]	Dec. 31, 2013 Centennial [Member]	Dec. 31, 2012 Centennial [Member]	Dec. 31, 2011 Centennial [Member]	Dec. 31, 2013 LOOP [Member]	Dec. 31, 2013 TAAE [Member]	Oct. 02, 2013 TAAE [Member]	Dec. 31, 2013 TACE [Member]	Dec. 31, 2013 TAME [Member]	Dec. 31, 2011 Marathon Oil Companies [Member]		Feb. 01, 2011 Marathon Oil Companies [Member] Revenue Bonds [Member]	Dec. 31, 2013 Marathon Oil Companies [Member] Revenue Bonds [Member]	Jul. 18, 2007 Marathon Oil Companies [Member] Revenue Bonds [Member]	Dec. 31, 2005 PFD [Member]	Jul. 18, 2007 PFD [Member] Related Party Credit Agreement [Member]	Dec. 31, 2013 PFD [Member] Related Party Credit Agreement [Member]	Dec. 31, 2011 PFD [Member] Related Party Credit Agreement [Member]	Oct. 28, 2010 PFD [Member] Related Party Credit Agreement [Member]	Jul. 18, 2007 PFD [Member] Euro Dollar Denominated Loans [Member] Related Party Credit Agreement [Member]	Jul. 18, 2007 PFD [Member] Euro Dollar Denominated Loans [Member] Minimum [Member] Related Party Credit Agreement [Member]	Jul. 18, 2007 PFD [Member] Euro Dollar Denominated Loans [Member] Maximum [Member] Related Party Credit Agreement [Member]	Dec. 31, 2013 Initial Agreement [Member] PFD [Member] Related Party Credit Agreement [Member]	Dec. 31, 2013 Amended Agreement [Member] PFD [Member] Related Party Credit Agreement [Member]
Related Party Transaction [Line Items]
Equity method investments, Ownership Percentage						50.00%			51.00%	43.00%	43.00%	60.00%	67.00%
Separation and distribution agreement date of Spin off transaction	May 25, 2011
Aggregate cash and cash equivalent balance				$ 1,625,000,000
Maximum duration of agreement for administrative services with former parent (in years)	1 year
Operating pipeline revenue from related parties included in other income						1,000,000	1,000,000	0
Selling, general and administrative expenses from transactions with related party														26,000,000
Long-term receivable from related party						2,000,000
Impairment of prepaid tariff					14,000,000
Line of Credit Facility, Initiation Date																											Jul. 18, 2007	Oct. 28, 2010
Line of Credit Facility, Maximum Borrowing Capacity																				2,900,000,000.0			4,400,000,000.0
Line of credit facility, expiration date																	Apr. 01, 2011				Jun. 30, 2011						May 04, 2012	Nov. 01, 2013
Long-term debt payable to related parties - borrowings	0	0	7,748,000,000																			7,750,000,000
Long-term debt payable to related parties – repayments	0	0	11,366,000,000													1,050,000,000						10,320,000,000
Interest rate, description																				higher of the prime rate or the sum of 0.5 percent, plus the federal funds rate				LIBOR plus a margin ranging from 0.25 percent to 1.125 percent
Debt instrument basis spread on variable rate																				0.50%					0.25%	1.125%
Debt instrument amount																		1,100,000,000
Loan Agreement interest Rate																		5.125%
Preferred stock redemption price (in USD per share)																			$ 2,000
Property, plant and equipment additions related to capitalized interest incurred by Marathon Oil on behalf of the company														2,000,000
Other Significant Noncash Transaction, Value of Consideration Received	$ 43,000,000	$ 0	$ 0											$ 57,000,000	[1]

[1] See Note 7.