Capitalized costs of unproved properties incurred for any combination mineral interests acquisitions and other costs not previously disclosed within this table.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 19
-Paragraph 59M

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Undeveloped acreage is considered to be those lease acres on which wells have not been drilled or completed to a point that would permit the production of commercial quantities of oil and gas regardless of whether or not such acreage contains proved reserves. Net acres is the sum of the fractional interest owned based on working interests or other economic arrangements.

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-Name Industry Guide
-Number 2
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The net change during the reporting period in the carrying amount of asset retirement obligations.

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The cash outflow to purchase of mineral interests in oil and gas properties for use in the normal oil and gas operations and not intended for resale.

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-Name Statement of Financial Accounting Standard (FAS)
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Reference 2: http://www.xbrl.org/2003/role/presentationRef
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-Name Statement of Financial Accounting Standard (FAS)
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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amounts in excess of the original cost of the regulated facilities within our gas pipeline businesses.

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Maximum coverage on damage to Property plant and equipment named windstorms.

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Offsetting increase related to changes in the timing and method of abandonment on certain of Transco's natural gas storage caverns.

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Percentage of Equity Acquired in a Business Combination.

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Percentage Of Undeveloped Property.

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Property, Plant, and Equipment.

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Property, Plant, and Equipment (Details Textual) (USD $) In Millions, unless otherwise specified	1 Months Ended	12 Months Ended
	Dec. 31, 2010	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008	Dec. 21, 2010
Property, Plant, and Equipment (Textuals)
Capitalized costs related to properties with unproved reserves not yet subject to depletion at Exploration & Production	$ 1,900	$ 1,900	$ 855
Percentage of the equity of Dakota-3 E&P Company LLC					100.00%
Net acres held by acquired company approximately					85,800
Percentage of acreage undeveloped approximately					85.00%
Acquisition of major acreage position in North Dakota's Bakken Shale oil play by Exploration and Production	949
Depreciation, depletion and amortization expense for property, plant, and equipment		1,507	1,469	1,310
Asset retirement obligations included in other liabilities and deferred income		745	712
Offsetting increase related to changes in the timing and method of abandonment on certain of Transco's natural gas storage caverns		31
Maximum coverage on damage to Property plant and equipment from windstorm	75	75
Regulated [Member]
Property, Plant and Equipment [Line Items]
Amounts in excess of the original cost of the regulated facilities within our gas pipeline businesses	$ 906	$ 906	$ 946
Period of straight-line amortization method		40 years