Pension, Other Postretirement Benefits and Savings Plans - Amounts Recognized in Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Prior service (credit) cost	$ (104)	$ (152)
Net actuarial loss	74	99
Gross amount recognized	(30)	(53)
Deferred income taxes	(9)	(1)
Minority shareholders’ equity	0	1
Net amount recognized	(39)	(53)
U.S. Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Prior service (credit) cost	(4)	(4)
Net actuarial loss	2,643	2,985
Gross amount recognized	2,639	2,981
Deferred income taxes	(128)	(177)
Minority shareholders’ equity	0	(62)
Net amount recognized	2,511	2,742
Non-U.S. Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Prior service (credit) cost	2	4
Net actuarial loss	693	838
Gross amount recognized	695	842
Deferred income taxes	(96)	(137)
Minority shareholders’ equity	0	(109)
Net amount recognized	$ 599	$ 596