Partners Capital Limited Partner Units (Details)	Mar. 31, 2013	Dec. 31, 2012
Limited Partners' Capital Account [Line Items]
Limited Partners' Capital Account, Units Outstanding	380,842,211	373,188,163
Limited Partners effective interest percentage	98.00%
General Partners effective interest percentage	2.00%
Common Unit [Member]
Limited Partners' Capital Account [Line Items]
Limited Partners' Capital Account, Units Outstanding	258,605,877	252,756,425
Class B Units [Member]
Limited Partners' Capital Account [Line Items]
Limited Partners' Capital Account, Units Outstanding	5,313,400	5,313,400
i-units [Member]
Limited Partners' Capital Account [Line Items]
Limited Partners' Capital Account, Units Outstanding	116,922,934	115,118,338
Units owned by General Partner [Member] | Common Unit [Member]
Limited Partners' Capital Account [Line Items]
Limited Partners' Capital Account, Units Outstanding	1,724,000	1,724,000
KMI and Consolidated Affiliates [Member] | Common Unit [Member]
Limited Partners' Capital Account [Line Items]
Limited Partners' Capital Account, Units Outstanding	20,563,455	19,314,003
Third Parties [Member] | Common Unit [Member]
Limited Partners' Capital Account [Line Items]
Limited Partners' Capital Account, Units Outstanding	236,318,422	231,718,422