Equity and Distributions, Summary of Changes in Outstanding Units (Details)	3 Months Ended
	Mar. 31, 2015
Common Units (Unrestricted) [Member]
Summary of changes in outstanding units [Roll Forward]
Beginning Balance (in units)	1,933,095,027
Common units issued in connection with at-the-market program (in units)	12,350,761
Common units issued in connection with DRIP and EUPP (in units)	1,940,832
Common units issued in connection with Step 2 of Oiltanking acquisition (in units)	36,827,517
Common units issued in connection with the vesting and exercise of unit options (in units)	291,250
Common units issued in connection with the vesting of phantom unit awards (in units)	519,247
Common units issued in connection with the vesting of restricted common unit awards (in units)	1,852,746
Forfeiture of restricted common unit awards (in units)	0
Acquisition and cancellation of treasury units in connection with the vesting of equity-based awards (in units)	(628,750)
Other (in units)	12,360
Ending Balance (in units)	1,986,260,990
Restricted Common Units [Member]
Summary of changes in outstanding units [Roll Forward]
Beginning Balance (in units)	4,229,790
Common units issued in connection with at-the-market program (in units)	0
Common units issued in connection with DRIP and EUPP (in units)	0
Common units issued in connection with Step 2 of Oiltanking acquisition (in units)	0
Common units issued in connection with the vesting and exercise of unit options (in units)	0
Common units issued in connection with the vesting of phantom unit awards (in units)	0
Common units issued in connection with the vesting of restricted common unit awards (in units)	(1,852,746)
Forfeiture of restricted common unit awards (in units)	(84,700)
Acquisition and cancellation of treasury units in connection with the vesting of equity-based awards (in units)	0
Other (in units)	0
Ending Balance (in units)	2,292,344
Common units [Member]
Summary of changes in outstanding units [Roll Forward]
Beginning Balance (in units)	1,937,324,817
Common units issued in connection with at-the-market program (in units)	12,350,761
Common units issued in connection with DRIP and EUPP (in units)	1,940,832
Common units issued in connection with Step 2 of Oiltanking acquisition (in units)	36,827,517
Common units issued in connection with the vesting and exercise of unit options (in units)	291,250
Common units issued in connection with the vesting of phantom unit awards (in units)	519,247
Common units issued in connection with the vesting of restricted common unit awards (in units)	0
Forfeiture of restricted common unit awards (in units)	(84,700)
Acquisition and cancellation of treasury units in connection with the vesting of equity-based awards (in units)	(628,750)
Other (in units)	12,360
Ending Balance (in units)	1,988,553,334