Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Statement of Comprehensive Income [Abstract]
Net earnings	$ 35	$ 15	$ 96	$ 38
Other comprehensive income (loss):
Foreign currency translation gain (loss), net of income taxes	(3)	1	0	(3)
Net unrecognized gain (loss) on postretirement obligations, net of income taxes	(2)	15	7	14
Other comprehensive income (loss), net of income tax	(5)	16	7	11
Total comprehensive income	$ 30	$ 31	$ 103	$ 49