Note 9 - Commitments, Guarantees and Contingencies (Details) - Environmental Matters (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Dec. 31, 2012	Jun. 30, 2012
Environmental Exit Cost [Line Items]
Probabilistic model cost estimate range	$ 396
Probabilistic model cost estimate range	798
Expected costs over next twelve months	62	57	59
Engineering Estimates [Member] | Illinois Environmental [Member]
Environmental Exit Cost [Line Items]
Environmental matters	42
Engineering Estimates [Member] | New Jersey Environmental [Member]
Environmental Exit Cost [Line Items]
Environmental matters	5
Engineering Estimates [Member] | Georgia And Florida [Member]
Environmental Exit Cost [Line Items]
Environmental matters	11
Engineering Estimates [Member] | North Carolina Environmental [Member]
Environmental Exit Cost [Line Items]
Environmental matters	11
Engineering Estimates [Member]
Environmental Exit Cost [Line Items]
Environmental matters	69
Amount Recorded [Member] | Illinois Environmental [Member]
Environmental Exit Cost [Line Items]
Environmental matters	250
Amount Recorded [Member] | New Jersey Environmental [Member]
Environmental Exit Cost [Line Items]
Environmental matters	151
Amount Recorded [Member] | Georgia And Florida [Member]
Environmental Exit Cost [Line Items]
Environmental matters	56
Amount Recorded [Member] | North Carolina Environmental [Member]
Environmental Exit Cost [Line Items]
Environmental matters	11
Amount Recorded [Member]
Environmental Exit Cost [Line Items]
Environmental matters	468
Illinois Environmental [Member]
Environmental Exit Cost [Line Items]
Probabilistic model cost estimate range	208
Probabilistic model cost estimate range	458
Expected costs over next twelve months	34
New Jersey Environmental [Member]
Environmental Exit Cost [Line Items]
Probabilistic model cost estimate range	146
Probabilistic model cost estimate range	240
Expected costs over next twelve months	15
Georgia And Florida [Member]
Environmental Exit Cost [Line Items]
Probabilistic model cost estimate range	42
Probabilistic model cost estimate range	100
Expected costs over next twelve months	8
North Carolina Environmental [Member]
Environmental Exit Cost [Line Items]
Expected costs over next twelve months	$ 5