Lease Commitments - Narrative (Details) - USD ($) $ in Millions	Sep. 30, 2019	Aug. 08, 2019	Jan. 01, 2019
Lessee, Lease, Description [Line Items]
Operating lease assets	$ 1,078
Total lease liabilities	1,139	$ 488
Finance lease agreement	100	86
Offshore and onshore drilling rigs
Lessee, Lease, Description [Line Items]
Operating lease assets	186
Compressors
Lessee, Lease, Description [Line Items]
Operating lease assets	174
Other field equipment
Lessee, Lease, Description [Line Items]
Operating lease assets	$ 97
Oil and gas exploration and development equipment | Minimum
Lessee, Lease, Description [Line Items]
Contract expiration term	2 years
Oil and gas exploration and development equipment | Maximum
Lessee, Lease, Description [Line Items]
Contract expiration term	7 years
Pipelines, rail cars, storage facilities, easements and real estate
Lessee, Lease, Description [Line Items]
Operating lease assets	$ 682
Real estate leases | Minimum
Lessee, Lease, Description [Line Items]
Contract expiration term	1 year
Real estate leases | Maximum
Lessee, Lease, Description [Line Items]
Contract expiration term	16 years
Oil and gas exploration and development equipment, real estate offices, compressors, and field equipment
Lessee, Lease, Description [Line Items]
Finance lease agreement	$ 100
Anadarko
Lessee, Lease, Description [Line Items]
Operating lease assets		498
Total lease liabilities		$ 574
Accounting Standards Update 2016-02
Lessee, Lease, Description [Line Items]
Operating lease assets			$ 772
Total lease liabilities			$ 772