Shareowners' Equity (Reclassifications from AOCI) (Details) (USD $)
In Millions, unless otherwise specified
 3 Months Ended 6 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Mar. 31, 2015
Mar. 31, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]        
INCOME FROM CONTINUING OPERATIONS $ 39 $ 3 $ 72 $ 17
Provision for income taxes (6) (8) [1] (13) (19)
NET INCOME 43 3 73 16
Amount Reclassified from Accumulated Other Comprehensive Income        
Accumulated Other Comprehensive Income (Loss) [Line Items]        
NET INCOME   8 25 18
Amount Reclassified from Accumulated Other Comprehensive Income | Employee Benefit Related Adjustments        
Accumulated Other Comprehensive Income (Loss) [Line Items]        
Prior service costs   (2)   (4)
Actuarial losses 12 [2] 11 24 23
INCOME FROM CONTINUING OPERATIONS 12 9 24 19
Provision for income taxes 0 (1) 0 (1)
NET INCOME 12 8 24 18
Amount Reclassified from Accumulated Other Comprehensive Income | Foreign Currency Translation        
Accumulated Other Comprehensive Income (Loss) [Line Items]        
Other reclassification adjustment     1  
INCOME FROM CONTINUING OPERATIONS     1  
Provision for income taxes     0  
NET INCOME     $ 1  
[1] Amounts for prior periods have been recast for discontinued operations.
[2] These accumulated other comprehensive income components are included in the computation of net periodic pension and retiree medical expense (see Note 18 for additional details).