Partners' Capital and Distributions (Details 5) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended
Mar. 31, 2012	Mar. 31, 2011
LTIP Vesting
LTIP unit vestings, fair value	$ 24
Changes in the noncontrolling interests in partners' capital
Beginning balance	524
Net income attributable to noncontrolling interests	7	3
Equity compensation expense	9
Other comprehensive income/(loss):
Ending Balance	516
Noncontrolling Interests
Changes in the noncontrolling interests in partners' capital
Beginning balance	524	231
Sale of noncontrolling interest in a subsidiary		306
Net income attributable to noncontrolling interests	7	3
Distribution to noncontrolling interest	(12)	(5)
Equity compensation expense	1	1
Other comprehensive income/(loss):
Reclassification adjustments	(6)
Deferred gain/(loss) on cash flow hedges, net	2
Ending Balance	516	536
PNG Long Term Incentive Plan Awards
LTIP Vesting
LTIP awards, issued (in units)	191,812
LTIP unit vestings, fair value	$ 16

Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which is directly or indirectly attributable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest).

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