Consolidated Statemetns of Comprehensive Income (Loss) (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement of Comprehensive Income [Abstract]
Tax on foreign currency translation	$ (2)	$ (52)	$ (46)
Tax on foreign currency translation reclassification adjustment recognized in income	0	0	0
Defined benefit plans:
Tax on amortization of prior service cost and unrecognized gains and losses included in total benefit cost	33	34	36
Tax on increase in net actuarial losses	(53)	(19)	(135)
Tax on immediate recognition of prior service cost and unrecognized gains and losses due to curtailments, settlements, and divestitures	0	67	13
Tax on deferred derivative gains	4	3	1
Tax on reclassification adjustment for amounts recognized in income	(1)	(3)	(1)
Tax on unrealized investment gains	0	(2)	1
Tax on unrealized investment gains reclassification adjustment recognized in income	0	2	0
Tax on deconsolidation of Venezuelan subsidiary	$ 0	$ 0	$ 0