EARNINGS PER COMMON SHARE - DILUTED (Details) - $ / shares	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Weighted average number of common shares outstanding diluted
Weighted average common shares outstanding (in shares)	1,685,000,000	1,177,000,000
Effect of dilutive options (in shares)	4,000,000	10,000,000
Diluted weighted average common shares outstanding (in shares)	1,689,000,000	1,187,000,000
Stock options
Weighted average number of common shares outstanding diluted
Antidilutive securities excluded from the diluted earnings per common share calculation (in shares)	29,882,142	13,545,193
Weighted average exercise price of antidilutive securities (in Canadian dollars per share)	$ 49.80	$ 57.71