Divestiture (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Jun. 30, 2018	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2016
Discontinued Operations and Disposal Groups [Abstract]
Disposal Group, Including Discontinued Operation, Percent Of Business Sold	49.90%	49.90%		50.10%
Proceeds from divestitures, net	$ 435	$ 534	$ 165
Gain on Sale of Investments	$ 308	$ 308	$ 0