EARNINGS PER COMMON SHARE - DILUTED (Details) - $ / shares	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Weighted average number of common shares outstanding diluted
Weighted average common shares outstanding (in shares)	1,695,000,000	1,628,000,000	1,690,000,000	1,404,000,000
Effect of dilutive options (in shares)	3,000,000	8,000,000	3,000,000	9,000,000
Diluted weighted average common shares outstanding (in shares)	1,698,000,000	1,636,000,000	1,693,000,000	1,413,000,000
Stock options
Weighted average number of common shares outstanding diluted
Antidilutive securities excluded from the diluted earnings per common share calculation (in shares)	30,245,645	13,416,763	30,063,894	13,480,978
Weighted average exercise price of antidilutive securities (in Canadian dollars per share)	$ 49.67	$ 57.98	$ 49.73	$ 57.84