Note 10 - Non-Wholly Owned Entities (Details) - SouthStar’s Revenues and Expenses (USD $) In Millions, unless otherwise specified	3 Months Ended												12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Variable Interest Entity [Line Items]
Operating revenues	$ 1,218	$ 574	$ 805	$ 1,612	$ 1,114	$ 526	$ 604	$ 1,318	$ 767	$ 291	$ 371	$ 876	$ 4,209	[1]	$ 3,562	[1]	$ 2,305	[1]
Operating income	166	70	113	290	187	52	90	261	114	19	58	236	639	[1]	590	[1]	427	[1]
Cost of goods sold													2,110	[1]	1,583	[1]	1,085	[1]
Operation and maintenance													887	[1]	816	[1]	497	[1]
Depreciation and amortization													397	[1]	394	[1]	182	[1]
Taxes other than income taxes													187	[1]	159	[1]	57	[1]
Total operating expenses													3,581	[1]	2,972	[1]	1,878	[1]
South Star [Member]
Variable Interest Entity [Line Items]
Operating revenues													687		576
Operating income													116		98
Cost of goods sold													491		411
Operation and maintenance													72		63
Depreciation and amortization													7		2
Taxes other than income taxes													1		2
Total operating expenses													$ 571		$ 478

[1] Amounts revised to include prior period adjustments. See Note 15 for additional information.