Supplemental Cash Flow Information (Details) - USD ($) $ in Millions			12 Months Ended
		Jan. 01, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Decrease (increase) in current assets:
Receivables, net			$ (1,468)	$ (457)	$ (870)
Inventories			(385)	(197)	(516)
Prepaid expenses and other			427	(77)	151
Increase (decrease) in current liabilities:
Accounts payable			1,534	304	1,842
Accrued expenses			(27)	(113)	21
Taxes other than income taxes payable			60	(73)	172
Income taxes payable			153	(684)	489
Changes in current assets and current liabilities			294	(1,297)	1,289
Cash Flows Related to Interest and Income Taxes
Interest paid in excess of amount capitalized, including interest on finance leases			452	463	457
Income taxes paid (refunded), net (see Note 15)			(116)	$ 1,361	$ 410
Cash paid for amounts included in the measurement of lease liabilities:
Operating leases - operating cash flows			441
Operating leases - investing cash flows			1
Changes in lease balances resulting from new and modified leases
Operating leases - changes in lease balances resulting from new and modified leases	[1]		1,756
Cash paid for amounts included in the measurement of lease liabilities:
Finance leases - operating cash flows			50
Finance leases - financing cash flows			34
Changes in lease balances resulting from new and modified leases
Finance leases - changes in lease balances resulting from new and modified leases			$ 239
Topic 842 [Member]
Changes in lease balances resulting from new and modified leases
Operating leases - changes in lease balances resulting from new and modified leases		$ 1,300

[1] Includes noncash activity of $1.3 billion for operating lease ROU assets recorded on January 1, 2019 upon adoption of Topic 842.