Note 3 - Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2013

Note 3 - Fair Value Measurements (Tables) [Line Items]

Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]

In millions	June 30, 2013		December 31, 2012		June 30, 2012
Long-term debt amortized cost	$	3,819	$	3,553	$	3,565
Long-term debt fair value (1)		4,070		4,057		4,043

Natural Gas Derivatives [Member]

Note 3 - Fair Value Measurements (Tables) [Line Items]

Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]

	Recurring fair values - Derivative instruments
	June 30, 2013					December 31, 2012					June 30, 2012
In millions	Assets (1)		Liabilities			Assets (1)		Liabilities			Assets (1)		Liabilities
Natural gas derivatives
Quoted prices in active markets (Level 1)	$	4	$	(51	)	$	8	$	(45	)	$	9	$	(103	)
Significant other observable inputs (Level 2)		78		(35	)		96		(30	)		148		(48	)
Netting of cash collateral		47		47			33		36			52		85
Total carrying value (2) (3)	$	129	$	(39	)	$	137	$	(39	)	$	209	$	(66	)
Interest rate derivatives
Significant other observable inputs (Level 2)	$	-	$	-		$	3	$	-		$	17	$	-

Money Market Funds [Member]

Note 3 - Fair Value Measurements (Tables) [Line Items]

Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]

In millions	At June 30, 2013		At December 31, 2012		At June 30, 2012
Money market funds (1)	$	48	$	66	$	76