CONSOLIDATED STATEMENT OF CHANGES IN EQUITY - USD ($) $ in Millions	Total	Common shares:	Other capital:	Retained earnings (accumulated deficit):	Accumulated other comprehensive loss:
Balance at beginning of year at Dec. 31, 2017		$ 944	$ 8,439	$ 1,078	$ (1,562)
Issued for exercise of stock options and vested restricted stock units		4	49
Repurchases of common shares (Note 15)		(15)	(351)
Share-based compensation			42
Other transactions, net			(7)
Net earnings (loss)	$ 748			748
Dividends on common shares				(995)
Adjustments related to new accounting pronouncements (Notes 15 and 17)				262
Other comprehensive income					672
Adjustments related to new accounting pronouncements and other (Note 15)					(262)
Balance at end of year at Dec. 31, 2018	$ 9,046	933	8,172	1,093	(1,152)
Dividends paid per common share	$ 1.32
Issued for exercise of stock options and vested restricted stock units		2	12
Repurchases of common shares (Note 15)		(3)	(57)
Share-based compensation			30
Other transactions, net			(5)
Net earnings (loss)	$ (76)			(76)
Dividends on common shares				(1,013)
Adjustments related to new accounting pronouncements (Notes 15 and 17)				(7)
Other comprehensive income					248
Balance at end of year at Dec. 31, 2019	$ 8,177	932	8,152	(3)	(904)
Dividends paid per common share	$ 1.36
Issued for exercise of stock options and vested restricted stock units		2	31
Share-based compensation			30
Other transactions, net			(5)
Net earnings (loss)	$ 797			797
Dividends on common shares				(383)
Other comprehensive income					82
Balance at end of year at Dec. 31, 2020	$ 8,731	$ 934	$ 8,208	$ 411	$ (822)
Dividends paid per common share	$ 0.51