Condensed Consolidated Statement of Financial Position (Parenthetical) - $ / shares |
Mar. 31, 2017 |
Sep. 30, 2016 |
|---|---|---|
| Statement of Financial Position [Abstract] | ||
| Common stock, par value | $ 0.01 | $ 0.01 |
| Common stock, shares authorized | 1,000,000,000 | 1,000,000,000 |
| Common stock, shares issued | 143,800,000 | 143,800,000 |
| Common stock, shares held in treasury | 12,600,000 | 13,600,000 |