Related Party Transactions - Additional Information (Detail) (USD $) In Millions, unless otherwise specified					3 Months Ended		6 Months Ended
	Jun. 30, 2014 TAAE	Oct. 01, 2013 TAAE	Jun. 30, 2014 TACE	Jun. 30, 2014 TAME	Jun. 30, 2014 Centennial	Jun. 30, 2013 Centennial	Jun. 30, 2014 Centennial	Jun. 30, 2013 Centennial	Dec. 31, 2013 Centennial	Jun. 30, 2014 Explorer	Jun. 30, 2014 LOCAP	Jun. 30, 2014 LOOP
Related Party Transaction [Line Items]
Equity method investments, ownership percentage	43.00%	43.00%	60.00%	67.00%	50.00%		50.00%			25.00%	59.00%	51.00%
Operating pipeline revenue from related parties included in other income, Centennial					$ 1	$ 1	$ 1	$ 1
Long-term receivable from related party					$ 2		$ 2		$ 2