|
Consolidated Balance Sheets (Parenthetical) (USD $)
|
Mar. 31, 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) | 418,935,311 | 411,824,039 |
| Common stock, shares outstanding (in shares) | 418,401,109 | 411,350,440 |