Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended				9 Months Ended
	Jun. 30, 2019	Dec. 31, 2018	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2019	Jun. 30, 2018
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
Income tax benefit for refinement of other adjustments	$ 2
Net pre-tax income (loss) tax benefit not recorded	$ 4		$ 7		$ 12	$ 20