Note 8 - Non-Wholly Owned Entities (Details) - Variable Interest Entities (USD $) In Millions, unless otherwise specified	Sep. 30, 2013		Dec. 31, 2012		Sep. 30, 2012		Dec. 31, 2011
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Current assets	$ 2,091		$ 2,668		$ 2,135
Goodwill and other intangible assets	2,063		1,933		1,913
Long-term assets and other deferred debits	9,750		9,540		9,455
Total assets	13,904	[1]	14,141	[2]	13,503	[1]
Current liabilities	2,407		3,338		2,764
Long-term liabilities and other deferred credits	7,934		7,368		7,341
Total Liabilities	10,341		10,706		10,105
Equity	3,563		3,435		3,398		3,339
Total liabilities and equity	13,904		14,141		13,503
South Star [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Current assets	192		201		152
Goodwill and other intangible assets	141
Long-term assets and other deferred debits	11		10		10
Total assets	344		211		162
Current liabilities	73		62		42
Total Liabilities	73		62		42
Equity	271		149		120
Total liabilities and equity	$ 344		$ 211		$ 162
South Star Percentage To Consolidated [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Current assets	9.00%		8.00%		7.00%
Goodwill and other intangible assets	7.00%
Total assets	2.00%		1.00%		1.00%
Current liabilities	3.00%		2.00%		2.00%
Total Liabilities	1.00%		1.00%
Equity	8.00%		4.00%		4.00%
Total liabilities and equity	2.00%		1.00%		1.00%

[1] Identifiable assets are those used in each segment's operations.

[2] Identifiable assets are those assets used in each segment's operations.