provisions (Tables)

12 Months Ended

Dec. 31, 2018


	Asset
	retirement		Employee-		Written put
(millions)	obligation		related		options 1		Other		Total
As at January 1, 2017	$	339	$	77	$	—	$	103	$	519
Additions		13		39		90		58		200
Reversal		(53)		(5)		(11)		(1)		(70)
Use		(6)		(75)		—		(40)		(121)
Interest effect 2		58		—		2		—		60
Effects of foreign exchange, net		—		—		1		—		1
As at December 31, 2017		351		36		82		120		589
Additions		6		124		207		72		409
Reversal		—		—		(17)		(5)		(22)
Use		(10)		(72)		(13)		(44)		(139)
Interest effect 2		(11)		—		10		—		(1)
Effects of foreign exchange, net		—		—		21		—		21
As at December 31, 2018	$	336	$	88	$	290	$	143	$	857
Current	$	6	$	35	$	—	$	37	$	78
Non-current		345		1		82		83		511
As at December 31, 2017	$	351	$	36	$	82	$	120	$	589
Current	$	8	$	84	$	9	$	28	$	129
Non-current		328		4		281		115		728
As at December 31, 2018	$	336	$	88	$	290	$	143	$	857

The additions for the year ended December 31, 2017, for written put options have been adjusted as set out in Note 18(c).

The difference of $(22) (2017 – $47) between the asset retirement obligation interest effect in this table and the amount included in the amount disclosed in Note 9 is in respect of the change in the discount rates applicable to the provision, such difference being included in the cost of the associated asset(s) by way of being included with (netted against) the additions detailed in Note 17.