Postretirement benefits (Tables)

6 Months Ended

Jun. 30, 2017

Compensation and Retirement Disclosure [Abstract]

Schedule of Net Benefit Costs [Table Text Block]

The components of net pension and other postretirement benefit costs (benefits) reflected in Net income in the Consolidated statements of operations were as follows:

	Three Months Ended June 30
	Pension Benefits									Other Postretirement Benefits
	U.S. Plans			Non-U.S. Plans			Total			U.S. Plans			Non-U.S. Plans		Total
(in millions of U.S. dollars)
2017
Service cost	$	16		$	4		$	20		$	1		$	1	$	2
Interest cost	26			7			33			—			—		—
Expected return on plan assets	(48		)	(10		)	(58		)	(1		)	—		(1		)
Amortization of net actuarial loss	—			1			1			—			—		—
Amortization of prior service cost	—			—			—			(23		)	—		(23		)
Curtailments	—			(8		)	(8		)	—			—		—
Net periodic (benefit) cost	$	(6	)	$	(6	)	$	(12	)	$	(23	)	$	1	$	(22	)
2016
Service cost	$	20		$	4		$	24		$	2		$	1	$	3
Interest cost	27			8			35			4			—		4
Expected return on plan assets	(42		)	(10		)	(52		)	(2		)	—		(2		)
Amortization of net actuarial loss	—			1			1			—			—		—
Net periodic cost	$	5		$	3		$	8		$	4		$	1	$	5

	Six Months Ended June 30
	Pension Benefits									Other Postretirement Benefits
	U.S. Plans			Non-U.S. Plans			Total			U.S. Plans			Non-U.S. Plans		Total
(in millions of U.S. dollars)
2017
Service cost	$	32		$	8		$	40		$	1		$	1	$	2
Interest cost	52			14			66			1			—		1
Expected return on plan assets	(95		)	(20		)	(115		)	(2		)	—		(2		)
Amortization of net actuarial loss	—			1			1			—			—		—
Amortization of prior service cost	—			—			—			(46		)	—		(46		)
Curtailments	—			(8		)	(8		)	—			—		—
Net periodic (benefit) cost	$	(11	)	$	(5	)	$	(16	)	$	(46	)	$	1	$	(45	)
2016
Service cost	$	37		$	9		$	46		$	4		$	1	$	5
Interest cost	54			16			70			9			—		9
Expected return on plan assets	(79		)	(20		)	(99		)	(4		)	—		(4		)
Amortization of net actuarial loss	—			2			2			—			—		—
Net periodic cost	$	12		$	7		$	19		$	9		$	1	$	10