Note 11 - Employee Retirement Plans (Details) - Summary of Net Periodic Benefit Cost - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Pension Plan [Member]
Note 11 - Employee Retirement Plans (Details) - Summary of Net Periodic Benefit Cost [Line Items]
Service cost	$ 22	$ 23
Interest cost	31	36
Expected return on plan assets	(42)	(45)
Amortization of prior service cost (credit)	1	2
Recognition of actuarial loss	7
Total pension and postretirement benefit expense	19	16
Other Postretirement Benefit Plan [Member]
Note 11 - Employee Retirement Plans (Details) - Summary of Net Periodic Benefit Cost [Line Items]
Service cost	2	3
Interest cost	7	8
Amortization of net loss		1
Amortization of prior service cost (credit)	(1)	(1)
Total pension and postretirement benefit expense	$ 8	$ 11