Consolidated Balance Sheet (Parenthetical) - $ / shares |
Dec. 31, 2018 |
Dec. 31, 2017 |
|---|---|---|
| Preferred stock, shares authorized (in shares) | 20,000,000 | 20,000,000 |
| Preferred stock, shares issued (in shares) | 0 | 0 |
| Class A Common Stock [Member] | ||
| Common stock, par value (in dollars per share) | $ 0.01 | $ 0.01 |
| Common stock, shares authorized (in shares) | 7,500,000,000 | 7,500,000,000 |
| Common stock, shares issued (in shares) | 5,389,309,175 | 5,507,854,670 |
| Common stock, shares outstanding (in shares) | 4,516,518,147 | 4,635,063,642 |
| Treasury stock (in shares) | 872,791,028 | 872,791,028 |
| Class B Common Stock [Member] | ||
| Common stock, par value (in dollars per share) | $ 0.01 | $ 0.01 |
| Common stock, shares authorized (in shares) | 75,000,000 | 75,000,000 |
| Common stock, shares issued (in shares) | 9,444,375 | 9,444,375 |
| Common stock, shares outstanding (in shares) | 9,444,375 | 9,444,375 |