Lease Commitments (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating Leased Assets [Line Items]
Non-cancelable term of operating and capital leases (in years)	1 year
Schedule of capitalized leased assets
Upstream	$ 676	$ 800
Downstream	99	98
All Other	0	0
Total	775	898
Less: Accumulated amortization	383	448
Net capitalized leased assets	392	450
Rental expenses incurred for operating leases
Minimum rentals	943	1,041	$ 1,080
Contingent rentals	2	2	1
Total	945	1,043	1,081
Less: Sublease rental income	7	9	14
Net rental expense	938	1,034	$ 1,067
Estimated future minimum lease payments (net of noncancelable sublease rentals) under operating and capital leases
Operating Leases, 2017	615
Capital Leases, 2017	22
Operating Leases, 2018	554
Capital Leases, 2018	20
Operating Leases, 2019	387
Capital Leases, 2019	21
Operating Leases, 2020	298
Capital Leases, 2020	12
Operating Leases, 2021	235
Capital Leases, 2021	12
Operating Leases, Thereafter	392
Capital Leases, Thereafter	145
Operating Leases, Total	2,481
Capital Leases, Total	232
Less: Amounts representing interest and executory costs	(125)
Net present values	107
Less: Capital lease obligations included in short-term debt	(14)
Long-term capital lease obligations	$ 93	$ 80
Maximum [Member]
Operating Leased Assets [Line Items]
Contingent rentals, renewal option term (in years)	25 years