Derivative financial instruments and risk management (Details 5) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Offsetting Assets
Gross Amount of Recognized Assets	$ 95	$ 105
Gross Amounts Offset in the Statement of Financial Position	0	0
Net Amount of Assets Presented in the Statement of Financial Position	95	105
Financial Instruments	(28)	(19)
Cash Collateral Received	0	0
Net Amount of Assets	67	86
Machinery, Energy & Transportation
Offsetting Assets
Gross Amount of Recognized Assets	23	14
Gross Amounts Offset in the Statement of Financial Position	0	0
Net Amount of Assets Presented in the Statement of Financial Position	23	14
Financial Instruments	(21)	(14)
Cash Collateral Received	0	0
Net Amount of Assets	2	0
Financial Products
Offsetting Assets
Gross Amount of Recognized Assets	72	91
Gross Amounts Offset in the Statement of Financial Position	0	0
Net Amount of Assets Presented in the Statement of Financial Position	72	91
Financial Instruments	(7)	(5)
Cash Collateral Received	0	0
Net Amount of Assets	$ 65	$ 86