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Shareholders' Equity (Details) - USD ($) | 3 Months Ended | 6 Months Ended | 39 Months Ended |  |
--- | --- | --- | --- | --- | ---
Jun. 30, 2015 | Jun. 30, 2014 | Jun. 30, 2015 | Jun. 30, 2014 | Jun. 30, 2015 | Nov. 30, 2014 | Apr. 30, 2012
Common Stock Programs |  |  |  |  |  |  |
Total cost of shares purchased |  |  | $ 550,000,000 |  |  |  |
Weighted average shares outstanding |  |  |  |  |  |  |
Shares for basic earnings per share (in shares) | 284,500,000 | 298,500,000 | 284,300,000 | 301,000,000 |  |  |
Common stock equivalents (in shares) | 2,200,000 | 3,100,000 | 2,600,000 | 3,400,000 |  |  |
Shares for diluted earnings per share (in shares) | 286,700,000 | 301,600,000 | 286,900,000 | 304,400,000 |  |  |
Number of shares excluded from the calculation of diluted earnings per share | 0 | 0 |  |  |  |  |
2012 - Share Repurchase Program [Member] |  |  |  |  |  |  |
Common Stock Programs |  |  |  |  |  |  |
Share repurchase authorization limit |  |  |  |  |  |  | $ 5,000,000,000.0
Shares purchased (in shares) | 3,000,000 | 7,400,000 | 5,500,000 | 14,600,000 | 67,600,000 |  |
Average price per share of stock repurchased | $ 100.92 | $ 87.67 | $ 100.57 | $ 85.59 |  |  |
Total cost of shares purchased | $ 300,000,000 | $ 650,000,000 | $ 550,000,000 | $ 1,300,000,000 | $ 4,900,000,000 |  |
Share repurchase, remaining authorization limit | $ 5,100,000,000 |  | $ 5,100,000,000 |  | $ 5,100,000,000 |  |
Share Repurchase Program of 2014 [Member] |  |  |  |  |  |  |
Common Stock Programs |  |  |  |  |  |  |
Share repurchase authorization limit |  |  |  |  |  | $ 5,000,000,000.0 |

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