Supplemental financial information - Amounts Reclassified out of AOCI (Details) - Reclassification out of Accumulated Other Comprehensive Income - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net actuarial gains (losses) of defined benefit plans
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Reclassified from other comprehensive income (loss), before tax	[1],[2]	$ 76	$ 78	$ 63
Tax Effect		(25)	(25)	(21)
Recognized within Net income, net of taxes		51	53	42
Prior service (cost) credit of defined benefit plans
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Reclassified from other comprehensive income (loss), before tax	[1],[2]	(5)	0	0
Tax Effect		2	0	0
Recognized within Net income, net of taxes		(3)	0	0
Derivative instruments
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Reclassified from other comprehensive income (loss), before tax		1	2	2
Tax Effect		0	(1)	(1)
Recognized within Net income, net of taxes		$ 1	$ 1	$ 1

[1] Detailed in Note 10.

[2] Pension expense is included in COR, R&D, SG&A and Restructuring charges/other.