Income Taxes (Net Deferred Income Tax Assets and Liabilities) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Deferred income tax assets related to
Employee benefits	$ 738	$ 877
Contingent and accrued liabilities	604	671
Operating loss and other carry-forwards	361	380
Inventories	14	24
Property	47	29
Derivatives	0	24
Other	94	99
Valuation allowance	(139)	(181)
Total	1,719	1,923
Deferred income tax liabilities related to
Property	622	401
Intangibles	439	805
Employee benefits	67	69
Deferred Tax Liabilities, Derivatives	4	0
Deferred Tax Liabilities, Undistributed Foreign Earnings	158	263
Other	222	180
Total	1,512	1,718
Deferred income tax assets – net	$ 207	$ 205
Minimum
Income Tax Examination [Line Items]
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2016
Tax Credit Carryforward, Expiration Date	Dec. 31, 2016
Maximum
Income Tax Examination [Line Items]
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2028
Tax Credit Carryforward, Expiration Date	Dec. 31, 2025