Postretirement benefits Schedule of net periodic benefit costs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan, Amount Recognized in Net Periodic Benefit Cost (Credit) and Other Comprehensive (Income) Loss, before Tax [Abstract]
(Increase) decrease in other comprehensive income, curtailment			$ 0
(Increase) decrease in other comprehensive income, settlement			0
Total (increase) decrease in other comprehensive (Income) Loss	$ 16	$ (545)	(15)
Pension Plan [Member] | UNITED STATES
Defined Benefit Plan, Amount Recognized in Net Periodic Benefit Cost (Credit) and Other Comprehensive (Income) Loss, before Tax [Abstract]
Service Cost	63	75	0
Interest Cost	105	103	0
Expected Return on Plan Assets	(189)	(165)	0
Amortization of (Gains) Losses	0	0	0
Amortization of Prior Service Cost (Credit)	0	0	0
Recognized Net (Gain) Loss Due to Curtailments	0	(117)	0
Recognized Net (Gain) Loss Due to Settlements	0	(2)	0
Net Periodic Benefit Cost	(21)	(106)	0
(Increase) decrease in Other Comprehensive Income (Loss), Net Actuarial (Gain) Loss)	(21)	(326)	0
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), before Tax	0	0	0
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, before Tax	0	0	0
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, before Tax	0	0	0
(Increase) decrease in other comprehensive income, curtailment	0	117
(Increase) decrease in other comprehensive income, settlement	1	2
Total (increase) decrease in other comprehensive (Income) Loss	(20)	(207)	0
Pension Plan [Member] | Non-US [Member]
Defined Benefit Plan, Amount Recognized in Net Periodic Benefit Cost (Credit) and Other Comprehensive (Income) Loss, before Tax [Abstract]
Service Cost	17	18	6
Interest Cost	27	30	21
Expected Return on Plan Assets	(42)	(39)	(29)
Amortization of (Gains) Losses	3	2	2
Amortization of Prior Service Cost (Credit)	0	(1)	0
Recognized Net (Gain) Loss Due to Curtailments	(27)	0	0
Recognized Net (Gain) Loss Due to Settlements	0	1	1
Net Periodic Benefit Cost	(22)	11	1
(Increase) decrease in Other Comprehensive Income (Loss), Net Actuarial (Gain) Loss)	(57)	49	(16)
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), before Tax	0	(8)	1
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, before Tax	(3)	0	0
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, before Tax	0	0	0
(Increase) decrease in other comprehensive income, curtailment	(6)	0
(Increase) decrease in other comprehensive income, settlement	0	(1)
Total (increase) decrease in other comprehensive (Income) Loss	(66)	40	(15)
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan, Amount Recognized in Net Periodic Benefit Cost (Credit) and Other Comprehensive (Income) Loss, before Tax [Abstract]
Service Cost	2	10	1
Interest Cost	4	17	0
Expected Return on Plan Assets	(5)	(8)	0
Amortization of (Gains) Losses	0	(1)	(1)
Amortization of Prior Service Cost (Credit)	(89)	(15)	0
Recognized Net (Gain) Loss Due to Curtailments	(37)	0	0
Recognized Net (Gain) Loss Due to Settlements	0	0	0
Net Periodic Benefit Cost	(125)	3	0
(Increase) decrease in Other Comprehensive Income (Loss), Net Actuarial (Gain) Loss)	(3)	17	0
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), before Tax	(23)	(395)	0
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, before Tax	0	0	0
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, before Tax	89	0	0
(Increase) decrease in other comprehensive income, curtailment	39	0	0
(Increase) decrease in other comprehensive income, settlement	0	0	0
Total (increase) decrease in other comprehensive (Income) Loss	$ 102	$ (378)	$ 0