Retirement Plans (Tables)

12 Months Ended

Dec. 31, 2017

Retirement Benefits [Abstract]

Schedule of Net Benefit Costs [Table Text Block]

The following table presents additional information about our international pension plans.

	December 31
Millions of dollars	2017		2016
Amounts recognized on the Consolidated Balance Sheets
Accrued employee compensation and benefits	$	15	$	16
Employee compensation and benefits	267		227
Pension plans in which projected benefit obligation exceeded plan assets
Projected benefit obligation	$	1,202	$	1,083
Fair value of plan assets	920		840
Pension plans in which accumulated benefit obligation exceeded plan assets
Accumulated benefit obligation	$	1,139	$	1,037
Fair value of plan assets	920		840

Schedule of Allocation of Plan Assets [Table Text Block]

The following table sets forth the fair values of assets held by our international pension plans by level within the fair value hierarchy.

Millions of dollars	Level 1		Level 2		Level 3		Total
Cash and equivalents	$	—	$	11	$	—	$	11
Common/collective trust funds (a)
Equity funds (b)	—		204		—		204
Bond funds (c)	—		323		46		369
Alternatives funds (d)	—		184		—		184
Real estate funds (e)	—		98		28		126
Other assets	7		22		17		46
Fair value of plan assets at December 31, 2017	$	7	$	842	$	91	$	940
Cash and equivalents	$	—	$	49	$	—	$	49
Common/collective trust funds (a)
Equity funds (b)	—		197		—		197
Bond funds (c)	—		232		44		276
Alternatives fund (d)	—		221		—		221
Real estate funds (e)	—		36		35		71
Other assets	5		20		26		51
Fair value of plan assets at December 31, 2016	$	5	$	755	$	105	$	865

(a) Common/collective trust funds are valued at the net asset value of units held by the plans at year-end.

(b) Strategy is to invest in diversified funds of global common stocks.

(c) Strategy is to invest in diversified funds of fixed income securities of varying geographies and credit quality and whose cash flows approximate the maturities of the benefit obligation.

(d) Strategy is to invest in a fund of diversifying investments, including but not limited to reinsurance, commodities and currencies.

(e) Strategy is to invest in diversified funds of real estate investment trusts and private real estate.

Schedule of Assumptions Used [Table Text Block]

Certain weighted-average actuarial assumptions used to determine benefit obligations of our international pension plans at December 31 were as follows:

	2017	2016
Discount rate	2.8%	2.9%
Rate of compensation increase	5.5%	4.8%

Certain weighted-average actuarial assumptions used to determine net periodic benefit cost of our international pension plans for the years ended December 31 were as follows:

	2017	2016	2015
Discount rate	2.9%	4.2%	4.1%
Expected long-term return on plan assets	4.2%	5.3%	5.9%
Rate of compensation increase	4.8%	5.4%	5.3%