CONSOLIDATED STATEMENT OF COMPREHENSIVE INCOME - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Comprehensive income:
Net earnings (loss)	$ 797	$ (76)	$ 748
Other comprehensive income (loss):
Foreign currency translation adjustments	18	26	(54)
Changes in unamortized actuarial loss, net of tax expense of $22 in 2020, $73 in 2019 and $235 in 2018	62	225	733
Changes in unamortized net prior service credit, net of tax (expense) benefit of $0 in 2020, ($1) in 2019 and $3 in 2018	2	(3)	(7)
Total comprehensive income	$ 879	$ 172	$ 1,420