Note 4 - Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2014

Fair Value Disclosures [Abstract]

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

	June 30, 2014					December 31, 2013					June 30, 2013
In millions	Assets (1)		Liabilities			Assets (1)		Liabilities			Assets (1)		Liabilities
Natural gas derivatives
Quoted prices in active markets (Level 1)	$	8	$	(38	)	$	6	$	(79	)	$	4	$	(51	)
Significant other observable inputs (Level 2)		57		(60	)		67		(79	)		78		(35	)
Netting of cash collateral		46		36			43		78			47		47
Total carrying value (2) (3)	$	111	$	(62	)	$	116	$	(80	)	$	129	$	(39	)

Fair Value, Liabilities Measured on Recurring Basis [Table Text Block]

In millions	June 30, 2014		December 31, 2013		June 30, 2013
Long-term debt carrying amount	$	3,807	$	3,813	$	3,819
Long-term debt fair value (1)		4,191		3,956		4,070