Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating activities
Net earnings	$ 5,046	$ 1,963	$ 5,173
Adjustments to reconcile net earnings to net cash provided by operating activities
Depreciation and amortization	1,161	1,195	1,215
Stock-based compensation	173	158	149
Deferred income taxes	(244)	3,448	(193)
Severance and restructuring charges	96	0	99
Gain on property sale	0	(198)	0
Gain on divestiture of IS&GS business	0	(73)	(1,201)
Gain on step acquisition of AWE	0	0	(104)
Changes in assets and liabilities
Receivables, net	(179)	(902)	598
Contract assets	(1,480)	390	(1,246)
Inventories	(119)	(79)	173
Accounts payable	914	(189)	(188)
Contract liabilities	(537)	353	(163)
Postretirement benefit plans	(3,574)	1,316	1,028
Income taxes	1,077	(1,210)	146
Other, net	804	304	(297)
Net cash provided by operating activities	3,138	6,476	5,189
Investing activities
Capital expenditures	(1,278)	(1,177)	(1,063)
Other, net	203	30	78
Net cash used for investing activities	(1,075)	(1,147)	(985)
Financing activities
Repurchases of common stock	(1,492)	(2,001)	(2,096)
Dividends paid	(2,347)	(2,163)	(2,048)
Proceeds from issuance of commercial paper, net	600	0	0
Special cash payment from divestiture of IS&GS business	0	0	1,800
Repayments of long-term debt	(750)	0	(952)
Other, net	(163)	(141)	(161)
Net cash used for financing activities	(4,152)	(4,305)	(3,457)
Net change in cash and cash equivalents	(2,089)	1,024	747
Cash and cash equivalents at beginning of year	2,861	1,837	1,090
Cash and cash equivalents at end of year	$ 772	$ 2,861	$ 1,837