General (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2011
Subsequent event - KMI acquisition of El Paso [Abstract]
Date definative agreement was announced	Oct. 16, 2011
Approximate enterprise value of KMI and El Paso once combined	$ 94,000.0
Miles of pipe of combined entity	80,000
Approximate purchase price for El Paso acquisition	$ 38,000.0
El Paso Corp's ownership interest in the limited partner units of El Paso Pipeline Partners LP	42.00%
El Paso Corp's general parter interest in El Paso Partners LP	2.00%
Period the acquisition is expected to close in	second quarter 2012
KMP [Member]
Schedule of Equity Method Investments [Line Items]
Ownership interest in outstanding limited partner interests of equity method investee	29.10%