Stock-Based Compensation and Earnings Per Share (Earnings Per Share and Diluted Share Equivalents) (Details) - USD ($)
$ / shares in Units, shares in Millions, $ in Millions
3 Months Ended 6 Months Ended
Mar. 31, 2016
Mar. 31, 2015
Mar. 31, 2016
Mar. 31, 2015
Computation of Basic and Diluted Earnings Per Share        
Income from continuing operations $ 172 $ 163 $ 305 $ 332
Income (loss) from discontinued operations, net of taxes (1) (6) 1 (8)
Net income $ 171 $ 157 $ 306 $ 324
Denominator:        
Denominator for basic earnings per share – weighted average common shares 130.8 132.2 131.1 132.6
Stock options 1.0 1.1 1.1 1.1
Performance shares, restricted stock and restricted stock units 0.5 0.4 0.5 0.4
Dilutive potential common shares 1.5 1.5 1.6 1.5
Denominator for diluted earnings per share – adjusted weighted average shares and assumed conversion 132.3 133.7 132.7 134.1
Basic        
Continuing operations $ 1.31 $ 1.23 $ 2.33 $ 2.50
Discontinued operations 0.00 (0.04) 0.00 (0.06)
Basic earnings per share 1.31 1.19 2.33 2.44
Diluted        
Continuing operations 1.30 1.22 2.30 2.48
Discontinued operations (0.01) (0.05) 0.01 (0.06)
Diluted earnings per share $ 1.29 $ 1.17 $ 2.31 $ 2.42
Employee Stock Option [Member]        
Diluted        
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount 0.6 0.0 0.0 0.0
New Accounting Pronouncement, Early Adoption, Effect [Member]        
Computation of Basic and Diluted Earnings Per Share        
Income from continuing operations     $ 3  
Diluted        
Continuing operations     $ 0.02