Risk Management Fair Value of Derivative Contracts (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2013	Dec. 31, 2012
Derivatives, Fair Value [Line Items]
Reduction to derivative assets and liabilities if netting had been used	$ 18	$ 17
Margin Deposit Assets	21	5
Fair value of debt, purchase accounting adjustments	624	638
Debt fair value adjustment, hedged instruments	519	602
Debt Instrument, Unamortized Discount	33	30
Asset derivatives	585	689
Liability derivatives	(60)	(34)
Unamortized premium	476	488
Amortization period of unamortized premium	18 years
Designated as Hedging Contracts [Member]
Derivatives, Fair Value [Line Items]
Asset derivatives	578	685
Liability derivatives	(56)	(30)
Commodity Contract [Member] \| Designated as Hedging Contracts [Member]
Derivatives, Fair Value [Line Items]
Asset derivatives	56	82
Liability derivatives	(53)	(29)
Commodity Contract [Member] \| Designated as Hedging Contracts [Member] \| Current-Fair value of derivative contracts [Member]
Derivatives, Fair Value [Line Items]
Asset derivatives	19	42
Liability derivatives	(45)	(18)
Commodity Contract [Member] \| Designated as Hedging Contracts [Member] \| Non-current-Fair value of derivative contracts [Member]
Derivatives, Fair Value [Line Items]
Asset derivatives	37	40
Liability derivatives	(8)	(11)
Commodity Contract [Member] \| Not Designated as Hedging Contracts [Member]
Derivatives, Fair Value [Line Items]
Asset derivatives	7	4
Liability derivatives	(4)	(4)
Commodity Contract [Member] \| Not Designated as Hedging Contracts [Member] \| Current-Fair value of derivative contracts [Member]
Derivatives, Fair Value [Line Items]
Asset derivatives	7	4
Liability derivatives	(4)	(3)
Commodity Contract [Member] \| Not Designated as Hedging Contracts [Member] \| Current-Assets held for Sale/ Accrued other current liabilities [Member]
Derivatives, Fair Value [Line Items]
Liability derivatives	0	(1)
Commodity Contract [Member] \| Not Designated as Hedging Contracts [Member] \| Other Long-term Investments [Member]
Derivatives, Fair Value [Line Items]
Asset derivatives	0	0
Interest Rate Swap [Member] \| Designated as Hedging Contracts [Member]
Derivatives, Fair Value [Line Items]
Asset derivatives	522	603
Liability derivatives	(3)	(1)
Interest Rate Swap [Member] \| Designated as Hedging Contracts [Member] \| Current-Fair value of derivative contracts [Member]
Derivatives, Fair Value [Line Items]
Asset derivatives	7	9
Liability derivatives	0	0
Interest Rate Swap [Member] \| Designated as Hedging Contracts [Member] \| Non-current-Fair value of derivative contracts [Member]
Derivatives, Fair Value [Line Items]
Asset derivatives	515	594
Liability derivatives	$ (3)	$ (1)

Debt fair value adjustment, hedged instruments

No definition available.

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- Definition

Fair value of debt, purchase accounting adjustments

+ References

No definition available.

+ Details

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Period Type:	instant

- Definition

Reduction to derivative assets and liabilities if netting had been used

+ References

No definition available.

+ Details

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Namespace Prefix:	kmp_
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- Definition

Period when adjustments to the carrying value of an interest-bearing hedged item are amortized upon discontinuation of the interest rate fair value hedge, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

+ Details

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- Definition

The amount of debt discount that was originally recognized at the issuance of the instrument that has yet to be amortized.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Accounting Principles Board Opinion (APB)

-Number 21

-Paragraph 16, 20

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 835

-SubTopic 30

-Section 45

-Paragraph 1A

-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28541-108399

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number APB14-1

-Paragraph 31

-Subparagraph b

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 835

-SubTopic 30

-Section 55

-Paragraph 8

-URI http://asc.fasb.org/extlink&oid=6584090&loc=d3e28878-108400

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- Definition

Amount as of the balance sheet date of the unamortized adjustment to the carrying value of an interest-bearing hedged item made under an effective interest rate fair value hedge that is amortized upon discontinuation of the interest rate fair value hedge.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 25

-Section 35

-Paragraph 9

-URI http://asc.fasb.org/extlink&oid=6439857&loc=d3e75592-113984

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 24

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

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- Definition

Fair value of the gross assets less the gross liabilities of a derivative asset or group of derivative assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 45

-Paragraph 6

-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41271-113958

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 10

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=7491637&loc=d3e13433-108611

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 45

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 15

-URI http://asc.fasb.org/extlink&oid=7491637&loc=d3e13495-108611

+ Details

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- Definition

Fair value of the gross liabilities less the gross assets of a derivative liability or group of derivative liabilities.

+ References

+ Details

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- Details

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- Definition

The amount of cash or securities placed with a broker or counterparty as security for a trading or derivatives securities position which was partially obtained with funds provided by the broker dealer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.8,17)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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