Consolidated Balance Sheets (Parenthetical) - $ / shares |
Sep. 30, 2015 |
Dec. 31, 2014 |
|---|---|---|
| Statement of Financial Position [Abstract] | ||
| Common stock, par value per share (in USD per share) | $ 0.01 | $ 0.01 |
| Common stock, shares issued (in shares) | 442,054,205 | 411,824,039 |
| Common stock, shares outstanding (in shares) | 441,411,091 | 411,350,440 |