Lease Commitments - Other Information (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019
Lessee, Lease, Description [Line Items]
Operating lease costs	$ 139	$ 321
Amortization of ROU assets	5	11
Interest on lease liabilities	1	1
Lease, Cost	304	665
Short-term lease cost	139	295
Variable lease cost	55	115
Operating cash flows		162
Investing cash flows		83
Financing cash flows		11
Cost of sales
Lessee, Lease, Description [Line Items]
Operating lease costs	133	271
Selling, general and administrative expenses
Lessee, Lease, Description [Line Items]
Operating lease costs	$ 26	$ 61