Property, Plant and Equipment (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Property, Plant and Equipment [Line Items]
Public Utilities, Property, Plant and Equipment, Common	$ 5,162	$ 2,114
Regulated assets as a percentage of total property plant and equipment	26.00%	14.00%
Depreciation	1,008	887	853
Natural gas, liquids, crude oil and carbon dioxide pipelines	10,205	7,759
Natural gas, liquids, carbon dioxide, and terminals station equipment	10,902	9,569
Natural gas, liquids (including linefill), and transmix processing	336	226
Other depreciable property, plant and equipment	1,656	1,454
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	(5,758)	(4,980)
Net depreciable property, plant and equipment	17,341	14,028
Land	921	770
Construction in Progress, Gross	1,341	798
Property, Plant and Equipment, Net	19,603	15,596
Asset Retirement Obligation	157	125
Asset Retirement Obligation, Current	$ 11	$ 11