Pension, Other Postretirement Benefits and Savings Plans - Narrative (Details) - USD ($) $ in Millions		3 Months Ended		12 Months Ended
	Jan. 01, 2016	Jun. 30, 2016	Dec. 31, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plans, contribution expenses				$ 111	$ 122	$ 125
Minimum
Defined Benefit Plan Disclosure [Line Items]
Expected contribution to funded non-U.S. pension plans in next year				25
Maximum
Defined Benefit Plan Disclosure [Line Items]
Expected contribution to funded non-U.S. pension plans in next year				50
Change in Assumptions for Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Benefits (credit) cost	$ (65)
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Settlement and curtailment charge				0	2	0
Benefits (credit) cost				(7)	(23)	(20)
Estimated net actuarial loss that will be amortized from AOCL into benefits cost in the next year				5
Estimated prior service credit that will be amortized from AOCL into benefits cost in the next year				8
Prescription drug subsidy				1
Postretirement benefits funded status				(282)	(290)
Pension benefit obligation			$ 291	286	294	291
AOCL adjustment				20	9
Prior Year Plans
Defined Benefit Plan Disclosure [Line Items]
Settlement and curtailment charge				13
United States
Defined Benefit Plan Disclosure [Line Items]
Settlement charge				32
Accumulated benefit obligation				$ 5,320	5,275
United States | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation				6.00%
United States | Fixed Income Securities
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation				94.00%
United States | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Settlement and curtailment charge			137	$ 29	0	137
Defined benefit plan, lump sum payments						190
Benefits (credit) cost				63	23	$ 190
Estimated net actuarial loss that will be amortized from AOCL into benefits cost in the next year				114
Postretirement benefits funded status				$ (353)	$ (313)
Weighted average discount rate				3.18%	3.23%	3.89%
Assumed weighted average long term rate of return				5.08%	5.33%	5.00%
Pension benefit obligation			5,338	$ 5,331	$ 5,285	$ 5,338
AOCL adjustment				2,599	2,611
United States | Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Benefits (credit) cost				(17)	(31)	$ (28)
Postretirement benefits funded status				$ (132)	$ (143)
Weighted average discount rate				3.02%	2.98%	3.59%
United Kingdom | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Settlement charge		$ 14
Settlement of benefit obligation		$ 41
Non-U.S.
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation				$ 3,017	$ 2,792
Non-U.S. | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation				10.00%
Non-U.S. | Fixed Income Securities
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation				90.00%
Non-U.S. | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Settlement and curtailment charge				$ 3	16	$ 2
Benefits (credit) cost				57	64	$ 84
Estimated net actuarial loss that will be amortized from AOCL into benefits cost in the next year				30
Postretirement benefits funded status				$ (303)	$ (356)
Weighted average discount rate				2.70%	3.37%	3.31%
Assumed weighted average long term rate of return				3.12%	3.81%	4.12%
Pension benefit obligation			$ 2,808	$ 3,109	$ 2,863	$ 2,808
AOCL adjustment				673	686
Non-U.S. | Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Benefits (credit) cost				10	8	$ 8
Postretirement benefits funded status				$ (150)	$ (147)
Weighted average discount rate				5.98%	6.31%	4.89%
Non-U.S. | Unfunded Plan
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation				$ 227	$ 219
Pension benefit obligation				251	239
AOCL adjustment				$ 59	$ 65