Note 4 - Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2014

Note 4 - Fair Value Measurements (Tables) [Line Items]

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

In millions	March 31, 2014		December 31, 2013		March 31, 2013
Long-term debt carrying amount	$	3,810	$	3,813	$	3,550
Long-term debt fair value (1)		4,095		3,956		4,006

Natural Gas and Interest Rate Derivatives [Member]

Note 4 - Fair Value Measurements (Tables) [Line Items]

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

	March 31, 2014					December 31, 2013					March 31, 2013
In millions	Assets (1)		Liabilities			Assets (1)		Liabilities			Assets (1)		Liabilities
Natural gas derivatives
Quoted prices in active markets (Level 1)	$	18	$	(38	)	$	6	$	(79	)	$	14	$	(38	)
Significant other observable inputs (Level 2)		50		(75	)		67		(79	)		49		(23	)
Netting of cash collateral		69		31			43		78			40		37
Total carrying value (2) (3)	$	137	$	(82	)	$	116	$	(80	)	$	103	$	(24	)
Interest rate derivatives
Significant other observable inputs (Level 2)	$	-	$	-		$	-	$	-		$	6	$	-