3M reported first-quarter earnings of $1.85 per share, an increase of 3.4% versus the first quarter of 2014. Sales declined 3.2% year-on-year to $7.6 billion. Organic local-currency sales grew 3.3%, and foreign currency translation reduced sales by 6.5% year-on-year.   Operating income was $1.7 billion and operating income margins for the quarter were 22.8%, up 0.9% points year-on-year. First-quarter net income was $1.2 billion, and the company converted 66% of net income to free cash flow.  ...