Intangible Assets (Notes)

12 Months Ended

Dec. 31, 2017

A reconciliation of the changes in the carrying amount of intangible assets is as follows:



	Coal rights	Software and other		Power sale contracts		Intangibles under development		Total
Cost
As at Dec. 31, 2015	178	256		223		15		672
Additions	—	—		—		21		21
Additions - capital lease	—	3		—		—		3
Retirements	—	(3	)	—		—		(3	)
Change in foreign exchange rates	—	(1	)	—		(1	)	(2	)
Transfers	—	13		—		(11	)	2
As at Dec. 31, 2016	178	268		223		24		693
Additions	—	31		—		20		51
Change in foreign exchange rates	—	(3	)	—		—		(3	)
Transfers	—	18		—		(15	)	3
As at Dec. 31, 2017	178	314		223		29		744

Accumulated amortization
As at Dec. 31, 2015	109	142		52		—		303
Amortization	6	24		8		—		38
Retirements	—	(3	)	—		—		(3	)
As at Dec. 31, 2016	115	163		60		—		338
Amortization	8	24		9		—		41
Change in foreign exchange rates	—	1		—		—		1
Transfers	2	—		(2	)	—		—
As at Dec. 31, 2017	125	188		67		—		380

Carrying amount
As at Dec. 31, 2015	69	114		171		15		369
As at Dec. 31, 2016	63	105		163		24		355
As at Dec. 31, 2017	53	126		156		29		364