Partners Capital Income Allocation and Declared Distributions (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2013	Jun. 30, 2010	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Distribution Made to Member or Limited Partner [Line Items]
Distribution Made to Member or Limited Partner, Distributions Declared, Per Unit			$ 4.98	$ 4.61	$ 4.40
Percent incentive distribution allocated to general partners income			100.00%
Limited Liability Company (LLC) or Limited Partnership (LP), Managing Member or General Partner, Ownership Interest			1.00%
Amount of cash distribution (usd per share)			$ 4.85	$ 4.58	$ 4.32
Incentive distribution waived as result of Kinderhawk acquisition	$ 7		$ 27	$ 28	$ 11
Partners' Capital Account, Distributions					170
Stock Dividends, Shares			6,488,946	6,601,402	6,369,724
Incentive distribution declared			1,404	1,174	881
Incentive Distribution, Distribution	384		1,322	1,147	848
Reduction to incentive distribution as a result of cash being distributed from interim capital transaction					168
Distributions from interim capital transactions		177
Limited Partner [Member]
Distribution Made to Member or Limited Partner [Line Items]
Amount of cash distribution (usd per share)		$ 0.56
Kinder Morgan, Inc. [Member]
Distribution Made to Member or Limited Partner [Line Items]
Related Party Transaction, Allocation of Non-cash Compensation Expenses			9	3	5
Kinder Morgan, Inc. [Member] | Total Partners' Capital [Member]
Distribution Made to Member or Limited Partner [Line Items]
Related Party Transaction, Allocation of Non-cash Compensation Expenses			$ 7
Noncontrolling Interest [Member] | General Partner [Member]
Distribution Made to Member or Limited Partner [Line Items]
Limited Liability Company (LLC) or Limited Partnership (LP), Managing Member or General Partner, Ownership Interest			2.00%