Note 2 - Significant Accounting Policies and Methods of Application (Details) - Property, Plant and Equipment (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 11,552	$ 10,938
Total PP&E, gross	11,552	10,938
Less accumulated depreciation	2,462	2,295
Total PP&E, net	9,090	8,643
Gas, Transmission and Distribution Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	9,105	8,371
Total PP&E, gross	9,105	8,371
Wells and Related Equipment and Facilities [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	1,202	1,170
Total PP&E, gross	1,202	1,170
Property, Plant and Equipment, Other Types [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	919	854
Total PP&E, gross	919	854
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	326	543
Total PP&E, gross	$ 326	$ 543