Business Combinations, Pro Forma Earnings Data (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Basic earnings per unit [Abstract]
As reported basic units outstanding (in units)									2,081.4	1,966.6	1,848.7
As reported basic earnings per unit (in dollars per unit)	$ 0.31	$ 0.30	$ 0.27	$ 0.32	$ 0.34	$ 0.33	$ 0.28	$ 0.33	$ 1.20	$ 1.28	$ 1.51
Diluted earnings per unit [Abstract]
As reported diluted units outstanding (in units)									2,089.1	1,998.6	1,895.2
As reported diluted earnings per unit (in dollars per unit)	$ 0.31	$ 0.30	$ 0.27	$ 0.32	$ 0.34	$ 0.32	$ 0.28	$ 0.32	$ 1.20	$ 1.26	$ 1.47
Eagle Ford Midstream Assets [Member]
Pro forma earnings data [Abstract]
Revenues										$ 27,148.5	$ 48,180.4
Costs and expenses										23,937.1	44,583.6
Operating income										3,585.0	3,856.3
Net income										2,594.4	2,896.1
Net income attributable to noncontrolling interests										37.2	46.1
Net income attributable to limited partners										$ 2,557.2	$ 2,850.0
Basic earnings per unit [Abstract]
Pro forma basic earnings per unit (in dollars per unit)										$ 1.30	$ 1.54
Diluted earnings per unit [Abstract]
Pro forma diluted earnings per unit (in dollars per unit)										$ 1.28	$ 1.50
Oiltanking Partners L.P. [Member]
Pro forma earnings data [Abstract]
Revenues											$ 48,087.5
Costs and expenses											44,509.0
Operating income											3,838.0
Net income											2,877.5
Net income attributable to noncontrolling interests											75.0
Net income attributable to limited partners											$ 2,802.5
Basic earnings per unit [Abstract]
As reported basic units outstanding (in units)											1,848.7
Pro forma basic units outstanding (in units)											1,903.5
Pro forma basic earnings per unit (in dollars per unit)											$ 1.47
Diluted earnings per unit [Abstract]
As reported diluted units outstanding (in units)											1,895.2
Pro forma diluted units outstanding (in units)											1,950.0
Pro forma diluted earnings per unit (in dollars per unit)											$ 1.44