Leases - Right of Use Assets and Lease Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2019	Oct. 01, 2019
Operating Leased Assets [Line Items]
Operating lease right-of-use assets		$ 380
Present value of lease liabilities	$ 376	$ 384
Other noncurrent assets
Operating Leased Assets [Line Items]
Operating lease right-of-use assets	374
Other current liabilities
Operating Leased Assets [Line Items]
Operating lease liabilities - current	112
Other noncurrent liabilities
Operating Leased Assets [Line Items]
Operating lease liabilities - noncurrent	$ 264