Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2015	Dec. 31, 2014
Income from Continuing Operations Before Income Tax Expense from Domestic and Foreign Operations
U.S. operations	$ 5,327	$ 4,677	$ 3,531
International operations	644	875	445
Income from continuing operations before income tax expense	5,971	5,552	3,976
Reconciliation of Income Tax Expense Related to Income from Continuing Operations Before Income Tax Expense
Income tax expense at statutory rates	1,956	1,782	1,320
U.S. state and Canadian provincial tax expense, net of federal income tax effect	118	133	86
Permanent differences:
Manufacturing deduction	(102)	(74)	(36)
Nontaxable gain on disposition (See Notes 3 and 10)			(114)
Other	(23)	(15)	9
Change in tax law	(17)		(32)
Tax effects of income associated with noncontrolling interests	(39)	(28)	(3)
Other, net	(23)	(21)	24
Income tax expense	1,870	1,777	1,254
Current:
Country	1,577	1,249	688
U.S. state / Canadian provincial	128	83	65
Total current	1,705	1,332	753
Deferred:
Country	151	362	447
U.S. state / Canadian provincial	14	83	54
Total deferred	165	445	501
Income tax expense	1,870	1,777	1,254
Deferred income tax assets:
Tax credit carryforwards				$ 33	$ 37
Net operating losses (NOLs)				423	436
Inventories				72	160
Compensation and employee benefit liabilities				331	358
Environmental liabilities				80	92
Other				139	178
Total deferred income tax assets				1,078	1,261
Less: Valuation allowance				(435)	(393)
Net deferred income tax assets				643	868
Deferred income tax liabilities:
Property, plant, and equipment				6,725	6,682
Deferred turnaround costs				394	356
Inventories				287	426
Investments				226	152
Other				71	73
Total deferred income tax liabilities				7,703	7,689
Net deferred income tax liabilities				7,060	6,821
Valuation Allowance Allocation
Deferred tax assets valuation allowance				435	393
Reconciliation of the Change in Unrecognized Tax Benefits RollForward
Balance as of beginning of year	989	950	341
Additions based on tax positions related to the current year	36	35	64
Additions for tax positions related to prior years	83	118	576
Reductions for tax positions related to prior years	(82)	(67)	(26)
Reductions for tax positions related to the lapse of applicable statute of limitations	(3)	(1)	(4)
Settlements	(59)	(46)	(1)
Balance as of end of year	964	989	950
Reconciliation of Unrecognized Tax Benefits to Uncertain Tax Position Liabilities
Unrecognized tax benefits	989	950	341	964	989
Tax refund claim not recognized in our financial statements				(570)	(554)
Reduction of deferred tax asset				(28)	0
Penalties, interest (net of U.S. federal and state income tax effect), and the U.S. federal income tax effect of state unrecognized tax benefits				25	49
Uncertain tax position liabilities				391	484
Income Taxes (Textual)
Income tax benefit related to discontinued operations	0	0	0
Increase in valuation allowance	42
Cumulative undistributed earnings of foreign subsidiaries				3,200
Tax refund claim not recognized in our financial statements				570	554
Income tax benefits if recognized that would impact the effective tax rate				757	768
Interest expense and penalties recognized	$ 5	$ 2	$ 12
Interest expense and penalties accrued				117	$ 141
Possible reduction to unrecognized tax benefit				370
Consolidated Statement Of Income [Member]
Deferred income tax assets:
Less: Valuation allowance				(429)
Valuation Allowance Allocation
Deferred tax assets valuation allowance				429
Additional Paid-in Capital [Member]
Deferred income tax assets:
Less: Valuation allowance				(6)
Valuation Allowance Allocation
Deferred tax assets valuation allowance				6
U.S. [Member]
Statutory Income Tax Rates Applicable to Income from Continuing Operations Before Income Tax Expense
Applicable statutory income tax rate	35.00%	35.00%	35.00%
Canada [Member]
Statutory Income Tax Rates Applicable to Income from Continuing Operations Before Income Tax Expense
Applicable statutory income tax rate	15.00%	15.00%	15.00%
U.K. [Member]
Statutory Income Tax Rates Applicable to Income from Continuing Operations Before Income Tax Expense
Applicable statutory income tax rate	20.00%	21.00%	23.00%
Ireland [Member]
Statutory Income Tax Rates Applicable to Income from Continuing Operations Before Income Tax Expense
Applicable statutory income tax rate	13.00%	13.00%	13.00%
Aruba [Member]
Statutory Income Tax Rates Applicable to Income from Continuing Operations Before Income Tax Expense
Applicable statutory income tax rate	7.00%	7.00%	7.00%
Domestic Tax Authority [Member]
Reconciliation of Income Tax Expense Related to Income from Continuing Operations Before Income Tax Expense
Income tax expense at statutory rates	$ 1,864	$ 1,637	$ 1,236
U.S. state and Canadian provincial tax expense, net of federal income tax effect	45	62	62
Permanent differences:
Manufacturing deduction	(102)	(74)	(36)
Nontaxable gain on disposition (See Notes 3 and 10)			(114)
Other	(18)	(16)	10
Change in tax law	0		(10)
Tax effects of income associated with noncontrolling interests	(39)	(28)	(3)
Other, net	(25)	(22)	44
Income tax expense	1,725	1,559	1,189
Current:
Country	1,513	1,196	635
U.S. state / Canadian provincial	85	59	36
Total current	1,598	1,255	671
Deferred:
Country	143	268	459
U.S. state / Canadian provincial	(16)	36	59
Total deferred	127	304	518
Income tax expense	1,725	1,559	1,189
Foreign Tax Authority [Member]
Reconciliation of Income Tax Expense Related to Income from Continuing Operations Before Income Tax Expense
Income tax expense at statutory rates	92	145	84
U.S. state and Canadian provincial tax expense, net of federal income tax effect	73	71	24
Permanent differences:
Manufacturing deduction	0	0	0
Nontaxable gain on disposition (See Notes 3 and 10)			0
Other	(5)	1	(1)
Change in tax law	(17)		(22)
Tax effects of income associated with noncontrolling interests	0	0	0
Other, net	2	1	(20)
Income tax expense	145	218	65
Current:
Country	64	53	53
U.S. state / Canadian provincial	43	24	29
Total current	107	77	82
Deferred:
Country	8	94	(12)
U.S. state / Canadian provincial	30	47	(5)
Total deferred	38	141	(17)
Income tax expense	$ 145	$ 218	$ 65
Income Tax Credit and Loss Carryforwards
NOL				1,465
State and Local Jurisdiction [Member]
Income Tax Credit and Loss Carryforwards
NOL				7,302
State and Local Jurisdiction [Member] | Minimum [Member]
Income Tax Credit and Loss Carryforwards
NOL, expiration	Dec. 31, 2016
State and Local Jurisdiction [Member] | Maximum [Member]
Income Tax Credit and Loss Carryforwards
NOL, expiration	Dec. 31, 2035
State and Local Jurisdiction [Member] | U S State Income Tax Credits Limited [Member]
Income Tax Credit and Loss Carryforwards
U.S. state income tax credits				$ 51
State and Local Jurisdiction [Member] | U S State Income Tax Credits Limited [Member] | Minimum [Member]
Income Tax Credit and Loss Carryforwards
Income tax credits, expiration	Dec. 31, 2016
State and Local Jurisdiction [Member] | U S State Income Tax Credits Limited [Member] | Maximum [Member]
Income Tax Credit and Loss Carryforwards
Income tax credits, expiration	Dec. 31, 2027