EARNINGS PER COMMON SHARE (Tables)

12 Months Ended

Dec. 31, 2019

Earnings per share [abstract]

Disclosure of earnings per common share

Earnings Attributable to Common Shareholders

For the years ended December 31
($ millions)	2019		2018
Earnings	1,492		1,278
Dividends on preferred shares	(123	)	(122	)
Cumulative dividends on preferred shares, not yet declared	(8	)	(3	)
Basic earnings attributable to common shareholders	1,361		1,153
Effect of after-tax interest on debentures to earnings	—		4
Diluted earnings attributable to common shareholders	1,361		1,157

Weighted Average Number of Common Shares

(In millions of shares, except as noted)	2019	2018
Issued common shares at January 1	508	503
Effect of shares issued on Acquisition	1	—
Effect of shares issued on exercise of options	3	1
Effect of conversion of convertible debentures	—	1
Basic weighted average number of common shares at December 31	512	505
Dilutive effect of debentures converted	—	2
Dilutive effect of share options on issue	2	2
Diluted weighted average number of common shares at December 31	514	509
Basic earnings per common share (dollars)	2.66	2.28
Diluted earnings per common share (dollars)	2.65	2.28