Consolidated Statement of Shareholders' Equity (Unaudited) - USD ($) $ in Millions	Total	Issued and Outstanding Common Shares [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]
Balance at Dec. 31, 2019	$ 2,376	$ 1	$ 1,770	$ 998	$ (393)
Balance, Shares at Dec. 31, 2019		56,900,000
Stock-based compensation, net of tax	(1)		(1)
Stock-based compensation, net of tax, shares		100,000
Net (loss) earnings	5			5
Net derivative gains (losses) on cash flow hedges:
Net gains (losses) arising during the period, net of tax of $(3) (2020 – $16)	(49)				(49)
Less: Reclassification adjustment for (gains) losses included in net (loss) earnings, net of tax of $(1) (2020 – $(2))	7				7
Foreign currency translation adjustments	(74)				(74)
Change in unrecognized gains (losses) and prior service cost related to pension and post-retirement benefit plans, net of tax	1				1
Stock repurchase	$ (59)		(59)
Stock repurchase, shares	(1,798,306)	(1,800,000)
Cash dividends declared	$ (25)			(25)
Balance at Mar. 31, 2020	2,181	$ 1	1,710	978	(508)
Balance, Shares at Mar. 31, 2020		55,200,000
Balance at Dec. 31, 2020	2,260	$ 1	1,717	846	(304)
Balance, Shares at Dec. 31, 2020		55,200,000
Stock-based compensation, net of tax	(1)		(1)
Stock-based compensation, net of tax, shares		100,000
Net (loss) earnings	(29)			(29)
Net derivative gains (losses) on cash flow hedges:
Net gains (losses) arising during the period, net of tax of $(3) (2020 – $16)	9				9
Less: Reclassification adjustment for (gains) losses included in net (loss) earnings, net of tax of $(1) (2020 – $(2))	(2)				(2)
Foreign currency translation adjustments	72				72
Change in unrecognized gains (losses) and prior service cost related to pension and post-retirement benefit plans, net of tax	5				5
Stock repurchase	$ (223)		(223)
Stock repurchase, shares	(629,959)	(5,100,000)
Balance at Mar. 31, 2021	$ 2,091	$ 1	$ 1,493	$ 817	$ (220)
Balance, Shares at Mar. 31, 2021		50,200,000