CONVERTIBLE DEBENTURES (Tables)

12 Months Ended

Dec. 31, 2018

Financial Instruments [Abstract]

Disclosure of convertible debentures

($ millions, except as noted)	Series F – 5.75%
Conversion price (dollars per share)	$29.53
Interest payable semi-annually in arrears on:	June 30 and December 31
Maturity Date	December 31, 2018
Balance at December 31, 2016	143
Conversions and redemptions	(52	)
Unwinding of discount rate	1
Deferred financing fee (net of amortization)	1
Balance at December 31, 2017	93
Conversions and redemptions	(93	)
Repayment at maturity	(2	)
Unwinding of discount rate	1
Deferred financing fee (net of amortization)	1
Balance at December 31, 2018	—