Goodwill and Other Intangible Assets - Other Intangible Assets Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2016	Mar. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Amortization of Intangible Assets	$ 24	$ 22	$ 48	$ 46
Future amortization expense, 2017	101		101
Future amortization expense, 2018	99		99
Future amortization expense, 2019	84		84
Future amortization expense, 2020	75		75
Future amortization expense, 2021	$ 64		$ 64