Debt (Details Textual) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2013	Dec. 31, 2014
Debt (Textual) [Abstract]
Maturities of long-term borrowings in 2016	$ 1,427
Maturities of long-term borrowings in 2017	1,081
Maturities of long-term borrowings in 2018	1,859
Maturities of long-term borrowings in 2019	3,014
Maturities of long-term borrowings in 2020	1,576
Classification of short-term debt as long-term debt	695
Capital Leased Assets [Line Items]
Capital lease obligations	$ 818		$ 858
Ownership Pre Unitization			33.00%
Ownership Post Unitization			29.00%
Short-term Debt [Line Items]
Maturity period of commercial paper (in days)	P90D
Letters of credit issued under revolving credit facilities	$ 340
Credit facilities remaining after commercial paper outstanding and issuance of letters of credit	6,200
Debt Instrument [Line Items]
Debt Instrument, Face Amount	23,778		$ 21,335
Gumusut Lease [Member]
Capital Leased Assets [Line Items]
Capital lease, initial non-cancelable term		15 years
Capital lease, cancelable term		5 years
Capital lease, additional term		5 years
Capital lease obligations		$ 906
Incremental Borrowing Rate		3.58%
Capital Leased Assets Net	707	$ 906	802
Capital Leases Other Accumulated Depreciation	122		20
1.5% Notes due 2018 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount	$ 750
Stated percentage of debt	1.50%
Floating rate notes due 2018 at 0.61% - 0.69% during 2015 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount	$ 250
Floating Rate Notes	three-month LIBOR, plus 0.33%
2.2% Notes due 2020 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount	$ 500
Stated percentage of debt	2.20%
Floating rate notes due 2022 at 1.18% - 1.26% during 2015 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount	$ 500
Floating Rate Notes	three-month LIBOR, plus 0.90%
3.35% Notes due 2025 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount	$ 500
Stated percentage of debt	3.35%
ConocoPhillips [Member]
Short-term Debt [Line Items]
Commercial paper program	$ 6,100
ConocoPhillips Qatar Funding Ltd. [Member]
Short-term Debt [Line Items]
Commercial paper program	900
Commercial paper outstanding	803		$ 860
Under Revolving Credit Facilities [Member]
Short-term Debt [Line Items]
Revolving credit facilities	7,000
Letters of credit outstanding	500
Minimum limit of debt for cross default provision	200
Letters of credit issued under revolving credit facilities	$ 0