Note 6 - Available-for-Sale Investments (Details) - Summary of Fair Value of Available-for-Sale Investments - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
US Government Agencies Debt Securities [Member]
Bonds, notes and other securities:
Amortized cost	$ 505	$ 759
Fair value	505	759
Total Short-Term Investments [Member]
Bonds, notes and other securities:
Amortized cost	505	759
Fair value	505	759
Asset-backed Securities [Member]
Bonds, notes and other securities:
Amortized cost	40	42
Fair value	35	38
Total Long-Term Investments [Member]
Bonds, notes and other securities:
Amortized cost	40	42
Fair value	$ 35	$ 38