Retirement Plans and Postretirement Medical Benefits (Pretax Amounts Recognized in AOCI) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
United States
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	$ 880,123	$ 918,641
Prior service credit	(512)	(144)
Transition asset	0	0
Total	879,611	918,497
Foreign
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	255,994	253,257
Prior service credit	(740)	(806)
Transition asset	(40)	(49)
Total	255,214	252,402
Nonpension postretirement benefit plans
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	59,174	97,955
Prior service credit	2,060	2,356
Total	$ 61,234	$ 100,311