CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN PARTNERS' CAPITAL - USD ($) $ in Millions	Total	Noncontrolling Interests	Limited Partners Class A Shares
Balance, beginning of period at Dec. 31, 2014	$ 9,381	$ 7,724	$ 1,657
Increase (Decrease) in Partners' Capital
Net income	593	500	93
Cash distributions to partners	(1,229)	(1,086)	(143)
Deferred tax asset	198		198
Change in ownership interest in connection with Exchange Right exercises (Note 8)		4	(4)
Sale of common units by a subsidiary	1,099	1,099
Other comprehensive loss	(518)	(514)	(4)
Other	2	2
Balance, end of period at Sep. 30, 2015	9,526	7,729	1,797
Balance, beginning of period at Dec. 31, 2015	9,234	7,472	1,762
Increase (Decrease) in Partners' Capital
Net income	538	436	102
Cash distributions to partners	(1,291)	(1,112)	(179)
Deferred tax asset	102		102
Change in ownership interest in connection with Exchange Right exercises (Note 8)		17	(17)
Sale of Series A preferred units by a subsidiary	1,509	1,509
Sale of common units by a subsidiary	283	283
Other comprehensive loss	0
Other	(1)	1	(2)
Balance, end of period at Sep. 30, 2016	$ 10,374	$ 8,606	$ 1,768