Retirement Plans and Postretirement Medical Benefits (Benefit Obligations and Funded Status) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015		Dec. 31, 2014		Dec. 31, 2013
United States
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation	$ 1,688,982		$ 1,866,914
Projected benefit obligation
Benefit obligation - beginning of year	1,868,176		1,622,591
Service cost	134		6,908		$ 13,981
Interest cost	74,331		77,655		74,370
Plan participants' contributions	0		0
Actuarial (gain) loss	(131,179)		306,718
Foreign currency changes	0		0
Plan Amendments	(428)		0
Settlement / curtailment	(3,678)		(16,867)
Special termination benefits	0		0
Benefits paid	(117,471)		(128,829)
Benefit obligation - end of year	1,689,885		1,868,176		1,622,591
Fair value of plan assets available for benefits
Fair value of plan assets - beginning of year	1,593,463		1,523,679
Actual return on plan assets	(19,173)		195,946
Company contributions	7,649		19,534
Plan participants' contributions	0		0
Settlement / curtailment	(3,678)		(16,867)
Foreign currency changes	0		0
Benefits paid	(117,471)		(128,829)
Fair value of plan assets - end of year	1,460,790		1,593,463		1,523,679
Amounts recognized in the Consolidated Balance Sheets
Non-current asset	271		300
Current liability	(9,088)		(6,590)
Non-current liability	(220,277)		(268,423)
Funded status	(229,094)		(274,713)
Foreign
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation	635,600		698,176
Projected benefit obligation
Benefit obligation - beginning of year	715,287		672,773
Service cost	2,229		3,565		6,272
Interest cost	24,261		28,518		27,365
Plan participants' contributions	8		59
Actuarial (gain) loss	(15,375)		89,695
Foreign currency changes	(53,945)		(52,750)
Plan Amendments	0		0
Settlement / curtailment	0		0
Special termination benefits	79		1,238
Benefits paid	(25,432)		(27,811)
Benefit obligation - end of year	647,112		715,287		672,773
Fair value of plan assets available for benefits
Fair value of plan assets - beginning of year	574,992		561,078
Actual return on plan assets	11,383		67,306
Company contributions	14,194		15,323
Plan participants' contributions	8		59
Settlement / curtailment	0		0
Foreign currency changes	(45,033)		(40,963)
Benefits paid	(25,432)		(27,811)
Fair value of plan assets - end of year	530,112		574,992		561,078
Amounts recognized in the Consolidated Balance Sheets
Non-current asset	11,566		5,813
Current liability	(1,031)		(1,008)
Non-current liability	(127,535)		(145,100)
Funded status	(117,000)		(140,295)
Nonpension postretirement benefit plans
Projected benefit obligation
Benefit obligation - beginning of year	253,980	[1]	231,153
Service cost	2,455		2,683		3,684
Interest cost	8,799		9,951		9,503
Plan participants' contributions	4,332		5,418
Actuarial (gain) loss	(31,253)		37,532
Foreign currency changes	(3,289)		(2,096)
Settlement / curtailment	0		(2,160)
Benefits paid	(23,146)		(28,501)
Benefit obligation - end of year	211,878	[1]	253,980	[1]	231,153
Fair value of plan assets available for benefits
Fair value of plan assets - beginning of year	0		0
Company contributions	18,814		23,083
Plan participants' contributions	4,332		5,418
Benefits paid	(23,146)		(28,501)
Fair value of plan assets - end of year	0		0		$ 0
Amounts recognized in the Consolidated Balance Sheets
Current liability	(19,406)		(22,113)
Non-current liability	(192,472)		(231,867)
Funded status	$ (211,878)		$ (253,980)

[1] The benefit obligation for the U.S. nonpension postretirement plans was $198 million and $231 million at December 31, 2015 and 2014, respectively.