Reconciliation of the numerators and denominators (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Earnings Per Share [Abstract]
Cash dividends common, per share	$ 1.16	$ 1.04	$ 0.88
Income (loss) from continuing operations	$ (847)	$ 1,439	$ 1,404
Income Available to Common Shareholders
Income (loss) from discontinued operations	0	(124)	189
Net Income (Loss) Attributable to Parent	$ (847)	$ 1,563	$ 1,215