Equity (Changes in Equity) (Parenthetical) (Details) (USD $)
3 Months Ended 6 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Mar. 31, 2015
Mar. 31, 2014
Statement of Stockholders' Equity [Abstract]        
Dividends per share $ 0.81 $ 0.77 $ 1.58 $ 1.48