EARNINGS PER COMMON SHARE - DILUTED (Details) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Weighted average number of common shares outstanding diluted
Weighted average common shares outstanding (in shares)	1,705,000,000	1,635,000,000	1,695,000,000	1,482,000,000
Effect of dilutive options (in shares)	3,000,000	7,000,000	4,000,000	8,000,000
Diluted weighted average common shares outstanding (in shares)	1,708,000,000	1,642,000,000	1,699,000,000	1,490,000,000
Stock options
Weighted average number of common shares outstanding diluted
Antidilutive securities excluded from the diluted earnings per common share calculation (in shares)	21,081,642	12,917,175	27,069,810	13,293,044
Weighted average exercise price of antidilutive securities (in Canadian dollars per share)	$ 52.17	$ 56.79	$ 50.37	$ 57.50