Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Transition tax non-cash charge		$ 77
Income tax net benefit recorded	$ 7
Transition tax refinement benefit	11
Income tax expense for refinement of other adjustments	4
Net pre-tax income (loss) tax benefit not recorded	$ 6	$ (2)