Leases - Supplemental Balance Sheet Information (Details) - USD ($) $ in Millions	Sep. 30, 2019	Jan. 01, 2019
Lessee, Lease, Description [Line Items]
Operating lease, liability, current		$ 45
Operating lease, liability, noncurrent		$ 214
Property and equipment, net
Lessee, Lease, Description [Line Items]
Operating lease, liability, current	$ 0
Finance lease, liability, current	35
Notes payable
Lessee, Lease, Description [Line Items]
Operating lease, liability, current	0
Finance lease, liability, current	7
Accrued liabilities
Lessee, Lease, Description [Line Items]
Operating lease, liability, current	38
Finance lease, liability, current	0
Long-term debt
Lessee, Lease, Description [Line Items]
Operating lease, liability, noncurrent	0
Finance lease, liability, noncurrent	28
Other liabilities
Lessee, Lease, Description [Line Items]
Operating lease, liability, noncurrent	168
Finance lease, liability, noncurrent	$ 0