Supplemental financial information - Amounts Reclassified out of AOCI (Details) - Reclassification out of Accumulated Other Comprehensive Income - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015
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]	$ 20	$ 14
Tax Effect		(6)	(4)
Recognized within Net income, net of taxes		14	10
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]	(1)	1
Tax Effect		0	0
Recognized within Net income, net of taxes		$ (1)	$ 1

[1] Detailed in Note 7.

[2] Pension expense is included in COR, R&D and SG&A in the Consolidated Statements of Income