Leases - Schedule of Cash Paid for Lease Liabilities and Right-of-Use Assets Obtained in Exchange for Lease Obligations (Details) $ in Millions	6 Months Ended
	Jun. 30, 2019 USD ($)
Leases [Abstract]
Operating cash flows from operating leases	$ 105
Operating cash flows from finance leases	0
Financing cash flows from finance leases	3
Operating leases	80
Finance leases	$ 1