Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2017

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Stock Option Plan

The following table summarizes the Company’s stock option plan as at December 31, 2017:

	Options outstanding				Nonvested options
	Number of options		Weighted average exercise price		Number of options		Weighted average grant date fair value
Outstanding, January 1, 2017	2,450,082		$	121.95	850,167		$	44.49
Granted	369,980		$	193.13	369,980		$	45.78
Exercised	(536,291	)	$	84.93	N/A		N/A
Vested	N/A		N/A		(328,265	)	$	42.97
Forfeited	(803,796	)	$	120.97	(208,955	)	$	47.21
Expired	(700	)	$	62.56	N/A		N/A
Outstanding, December 31, 2017	1,479,275		$	150.64	682,927		$	45.46
Vested or expected to vest at December 31, 2017(1)	1,419,564		$	149.05	N/A		N/A
Exercisable, December 31, 2017	796,348		$	119.32	N/A		N/A

⁽¹⁾ As at December 31, 2017, the weighted average remaining term of vested or expected to vest options was 7.0 years with an aggregate intrinsic value of $114 million.

Stock Options Outstanding and Exercisable

The following table provides the number of stock options outstanding and exercisable as at December 31, 2017 by range of exercise price and their related intrinsic aggregate value, and for options outstanding, the weighted-average years to expiration. The table also provides the aggregate intrinsic value for in-the-money stock options, which represents the amount that would have been received by option holders had they exercised their options on December 31, 2017 at the Company’s closing stock price of $229.66.

	Options outstanding						Options exercisable
Range of exercise prices	Number of options	Weighted average years to expiration	Weighted average exercise price		Aggregate intrinsic value (millions)		Number of options	Weighted average exercise price		Aggregate intrinsic value (millions)
$36.29 – $117.48	416,270	3.7	$	84.50	$	60	416,270	$	84.50	$	60
$117.49 – $165.95	359,997	6.8	$	141.38	$	32	200,362	$	128.43	$	20
$165.96 – $190.42	415,914	6.1	$	182.48	$	20	106,458	$	169.28	$	6
$190.43 – $222.88	287,094	6.7	$	212.05	$	5	73,258	$	219.60	$	1
Total(1)	1,479,275	5.7	$	150.64	$	117	796,348	$	119.32	$	87

⁽¹⁾ As at December 31, 2017, the total number of in-the-money stock options outstanding was 1,479,275 with a weighted-average exercise price of $150.64. The weighted-average years to expiration of exercisable stock options is 4.9 years.

Weighted-Average Fair Value Assumptions

The weighted average fair value assumptions were approximately:

	2017			2016			2015
Expected option life (years)(1)	5.48			5.25			5.25
Risk-free interest rate(2)	1.85		%	1.21		%	1.10		%
Expected stock price volatility(3)	27		%	27		%	26		%
Expected annual dividends per share(4)	$	2.0010		$	1.4000		$	1.4000
Estimated forfeiture rate(5)	2.8		%	2.0		%	1.2		%
Weighted average grant date fair value of options granted during the year	$	45.78		$	39.01		$	55.28

⁽¹⁾ Represents the period of time that awards are expected to be outstanding. Historical data on exercise behaviour or, when available, specific expectations regarding future exercise behaviour were used to estimate the expected life of the option.

⁽²⁾ Based on the implied yield available on zero-coupon government issues with an equivalent remaining term at the time of the grant.

⁽³⁾ Based on the historical stock price volatility of the Company’s stock over a period commensurate with the expected term of the option.

⁽⁴⁾ Determined by the current annual dividend at the time of grant. The Company does not employ different dividend yields throughout the contractual term of the option. On May 10, 2017, the Company announced an increase in its quarterly dividend to $0.5625 per share, representing $2.2500 on an annual basis.

⁽⁵⁾ The Company estimated forfeitures based on past experience. The rate is monitored on a periodic basis.

Schedule of Options Exercised

The following table provides information related to all options exercised in the stock option plan during the years ended December 31:

(in millions of Canadian dollars)	2017		2016		2015
Total intrinsic value	$	36	$	30	$	72
Cash received by the Company upon exercise of options	$	45	$	21	$	43

Summary of Performance Share Units Plan

The following table summarizes information related to the Company’s PSUs as at December 31:

	2017		2016
Outstanding, January 1	373,593		348,276
Granted	134,991		147,157
Units, in lieu of dividends	3,571		4,010
Settled	(133,728	)	(83,466	)
Forfeited	(44,399	)	(42,384	)
Outstanding, December 31	334,028		373,593

Summary of Deferred Share Units Plan

The following table summarizes information related to the DSUs as at December 31:

	2017		2016
Outstanding, January 1	234,036		318,176
Granted	23,932		31,069
Units, in lieu of dividends	1,969		2,798
Settled	(33,682	)	(87,996	)
Forfeited	(69,708	)	(30,011	)
Outstanding, December 31	156,547		234,036

Summary of Total Share Based Liabilities Paid

The following table summarizes the total share based liabilities paid for each of the years ended December 31:

(in millions of Canadian dollars)	2017		2016		2015
Plan
DSUs	$	6	$	17	$	3
PSUs	31		31		79
Other	2		—		8
Total	$	39	$	48	$	90