CONSOLIDATED BALANCE SHEETS (Unaudited) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Current assets
Cash and cash equivalents	$ 736	$ 529	[1]
Accounts receivable, net of allowance	1,085	1,114	[1]
Inventories	352	338	[1]
Fair value of derivative contracts	33	55	[1]
Assets held for sale	32	211	[1]
Other current assets	124	130	[1]
Total current assets	2,362	2,377	[1]
Property, plant and equipment, net	22,584	22,330	[1]
Investments	1,880	1,864	[1]
Goodwill	5,412	5,417	[1]
Other intangibles, net	1,123	1,142	[1]
Fair value of derivative contracts	552	634	[1]
Deferred charges and other assets	1,239	1,212	[1]
Total Assets	35,152	34,976	[1]
Current liabilities
Current portion of debt	1,127	1,155	[1]
Accounts payable	983	1,091	[1]
Accrued interest	184	327	[1]
Fair value of derivative contracts	49	21	[1]
Accrued other current liabilities	851	653	[1]
Total current liabilities	3,194	3,247	[1]
Long-term debt
Outstanding	16,829	15,907	[1]
Debt fair value adjustments	1,586	1,698	[1]
Total long-term debt	18,415	17,605	[1]
Deferred income taxes	254	249	[1]
Fair value of derivative contracts	11	13	[1]
Other long-term liabilities and deferred credits	1,044	1,100	[1]
Total long-term liabilities and deferred credits	19,724	18,967	[1]
Total Liabilities	22,918	22,214	[1]
Commitments and contingencies (Notes 3 and 9)
Partners' Capital
Common Units	5,137	4,723	[1]
General partner	3,008	4,026	[1]
Accumulated other comprehensive income	79	168	[1]
Total Kinder Morgan Energy Partners, L.P. Partners' Capital	11,913	12,495	[1]
Noncontrolling interests	321	267	[1]
Total Partners' Capital	12,234	12,762	[1]
Total Liabilities and Partners' Capital	35,152	34,976	[1]
Class B [Member]
Partners' Capital
Common Units	13	14	[1]
i-units [Member]
Partners' Capital
Common Units	$ 3,676	$ 3,564	[1]

[1] Retrospectively adjusted as discussed in Note 1.