Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Operating Activities
Net earnings	$ 640	$ 556
Adjustments to reconcile to net cash used in operating activities:
Depreciation and amortization	104	103
Stock-based compensation	17	14
Deferred income taxes	(16)	(35)
Changes in assets and liabilities:
Accounts receivable, net	(773)	(514)
Inventoried costs, net	(117)	(89)
Prepaid expenses and other assets	(46)	(4)
Accounts payable and other liabilities	(466)	(364)
Income taxes payable	152	174
Retiree benefits	86	105
Other, net	(20)	(6)
Net cash used in operating activities	(439)	(60)
Investing activities
Capital expenditures	(216)	(298)
Other, net	2	0
Net cash used in investing activities	(214)	(298)
Financing activities
Common stock repurchases	(229)	(282)
Payments of long-term debt	0	(107)
Cash dividends paid	(166)	(159)
Payments of employee taxes withheld from share-based awards	(90)	(137)
Other, net	0	1
Net cash used in financing activities	(485)	(684)
Decrease in cash and cash equivalents	(1,138)	(1,042)
Cash and cash equivalents, beginning of year	2,541	2,319
Cash and cash equivalents, end of period	$ 1,403	$ 1,277