CONSOLIDATED STATEMENT OF COMPREHENSIVE INCOME - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement Of Income And Comprehensive Income [Abstract]
Net earnings (loss)	$ 128	$ 317	$ (161)	$ 586
Other comprehensive income (loss):
Foreign currency translation adjustments	11	(16)	25	(31)
Changes in unamortized actuarial loss, net of tax expense of $9, $63, $120, and $82	29	199	373	253
Changes in unamortized net prior service credit, net of tax benefit of $0, $1, $0 and $1	(1)	0	(1)	(1)
Total other comprehensive income	39	183	397	221
Total comprehensive income	$ 167	$ 500	$ 236	$ 807