Related Party Transactions - Purchases from Related Parties (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Related Party Transaction [Line Items]
Purchases from related parties	$ 130	$ 79	$ 289	$ 151
Centennial
Related Party Transaction [Line Items]
Purchases from related parties	(2)	0	7	0
Explorer
Related Party Transaction [Line Items]
Purchases from related parties	9	0	22	0
LOCAP
Related Party Transaction [Line Items]
Purchases from related parties	5	4	10	8
LOOP
Related Party Transaction [Line Items]
Purchases from related parties	12	11	65	21
TAAE
Related Party Transaction [Line Items]
Purchases from related parties	26	0	42	0
TACE
Related Party Transaction [Line Items]
Purchases from related parties	30	24	57	50
TAME
Related Party Transaction [Line Items]
Purchases from related parties	48	37	82	67
Other equity method investees
Related Party Transaction [Line Items]
Purchases from related parties	$ 2	$ 3	$ 4	$ 5