Basis of Presentation (Details) - USD ($) $ in Millions	Jun. 30, 2020	Oct. 01, 2019	Sep. 30, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease right-of-use assets	$ 500		$ 0
Operating lease liabilities	$ 508
Accounting Standards Update 2016-02 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease right-of-use assets		$ 500
Operating lease liabilities		$ 500