CONSOLIDATED STATEMENT OF COMPREHENSIVE INCOME - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Statement Of Income And Comprehensive Income [Abstract]
Net earnings	$ 482	$ 283	$ 2,191	$ 505
Other comprehensive income (loss):
Foreign currency translation adjustments	(25)	11	(1)	(14)
Changes in unamortized actuarial loss, net of tax expense of $10, $6, $55 and $30	29	19	170	86
Changes in unamortized net prior service credit, net of tax expense of $0, $0, $0 and $0	1	0	2	2
Total other comprehensive income	5	30	171	74
Total comprehensive income	$ 487	$ 313	$ 2,362	$ 579