Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating activities
Net earnings	$ 3,189	$ 2,248	$ 3,229
Adjustments to reconcile to net cash provided by operating activities:
Depreciation and amortization	1,267	1,265	800
Mark-to-market pension and OPB expense	1,034	1,800	655
Stock-based compensation	90	127	86
Deferred income taxes	210	(509)	234
Changes in assets and liabilities:
Accounts receivable, net	(285)	122	202
Unbilled receivables, net	160	(335)	(297)
Inventoried costs, net	18	(135)	(37)
Prepaid expenses and other assets	(147)	(78)	(56)
Accounts payable and other liabilities	719	617	381
Income taxes payable, net	(238)	(63)	(258)
Retiree benefits	(1,678)	(703)	(1,083)
Other, net	(34)	(59)	(29)
Net cash provided by operating activities	4,305	4,297	3,827
Investing activities
Acquisition of Orbital ATK, net of cash acquired	0	0	(7,657)
Capital expenditures	(1,420)	(1,264)	(1,249)
Proceeds from Sale of Equipment to a Customer	205	0	0
Other investing activities, net	4	57	28
Net cash used in investing activities	(1,211)	(1,207)	(8,878)
Financing activities
Payments of long-term debt	(1,027)	(500)	(2,276)
Net proceeds from issuance of long-term debt	2,239	0	0
Payments to credit facilities	(78)	(31)	(320)
Net (repayments of) borrowings on commercial paper	0	(198)	198
Common stock repurchases	(490)	(744)	(1,263)
Cash dividends paid	(953)	(880)	(821)
Payments of employee taxes withheld from share-based awards	(66)	(65)	(85)
Other financing activities, net	(57)	(6)	(28)
Net cash used in financing activities	(432)	(2,424)	(4,595)
Increase (decrease) in cash and cash equivalents	2,662	666	(9,646)
Cash and cash equivalents, beginning of year	2,245	1,579	11,225
Cash and cash equivalents, end of year	$ 4,907	$ 2,245	$ 1,579