| Stock-Based Compensation Expense | |||||||||
| Years ended December 31 | |||||||||
| (Millions) | 2013 | 2012 | 2011 | ||||||
| Cost of sales | $ | 27 | $ | 27 | $ | 29 | |||
| Selling, general and administrative expenses | 183 | 167 | 192 | ||||||
| Research, development and related expenses | 30 | 29 | 32 | ||||||
| Stock-based compensation expenses | $ | 240 | $ | 223 | $ | 253 | |||
| Income tax benefits | $ | (71) | $ | (67) | $ | (80) | |||
| Stock-based compensation expenses, net of tax | $ | 169 | $ | 156 | $ | 173 | |||