CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating activities:
Net income	$ 1,026	$ 693	$ 724
Less: (income) loss from discontinued operations, net of tax	(205)	76	(91)
Income from continuing operations	821	769	633
Depreciation of property, plant and equipment	182	172	156
Amortization of intangibles and other assets	59	53	42
Deferred income tax (benefit) provision	(7)	(8)	27
Stock-based employee compensation expense	60	53	49
Contributions to employee savings plans in common stock	115	106	102
Amortization of pension and postretirement benefit plans net loss and prior service cost	68	59	48
Loss (gain) on sale of property, plant and equipment	4	(31)	(5)
Gain on sale of the Crestview Aerospace and TCS businesses	(42)	0	0
Debt retirement charges	69	0	7
Other non-cash items	6	15	26
Changes in operating assets and liabilities, excluding amounts from acquisitions, divestitures, and discontinued operations:
Billed receivables	(195)	(18)	1
Contract assets	(246)	0	0
Contracts in process	0	(70)	26
Inventories	57	(69)	22
Prepaid expenses and other current assets	(75)	(58)	(23)
Accounts payable, trade	158	99	(5)
Accrued employment costs	0	28	10
Accrued expenses	55	32	(6)
Contract liabilities	108	0	0
Advance payments and billings in excess of costs incurred	0	13	(73)
Income taxes	9	(39)	33
All other operating activities	(164)	(121)	(48)
Net cash from operating activities from continuing operations	1,042	985	1,022
Investing activities:
Business acquisitions, net of cash acquired	(369)	(316)	(388)
Proceeds from the sale of businesses, net of closing date cash balances	535	18	561
Capital expenditures	(232)	(224)	(210)
Dispositions of property, plant and equipment	3	74	21
Other investing activities	(28)	(5)	6
Net cash used in investing activities from continuing operations	(91)	(453)	(10)
Proceeds from sale of senior notes	1,798	0	547
Financing activities:
Repurchases, redemptions and maturities of senior notes	(1,865)	0	(856)
Borrowings under revolving credit facility	501	1,328	819
Repayments of borrowings under revolving credit facility	(501)	(1,328)	(819)
Common stock repurchased	(322)	(180)	(373)
Dividends paid	(254)	(236)	(220)
Proceeds from exercise of stock options	149	46	53
Proceeds from employee stock purchase plan	33	32	31
Repurchases of common stock to satisfy tax withholding obligations	(31)	(18)	(21)
Debt issue costs	(15)	0	(10)
Other financing activities	(13)	(10)	(7)
Net cash used in financing activities from continuing operations	(520)	(366)	(856)
Effect of foreign currency exchange rate changes on cash and cash equivalents	(15)	20	(13)
Net cash from (used in) discontinued operations:
Operating activities	(10)	117	19
Investing activities	(2)	(4)	(6)
Net cash (used in) from discontinued operations	(12)	113	13
Net increase in cash and cash equivalents	404	299	156
Cash and cash equivalents, beginning of the year	662	363	207
Cash and cash equivalents, end of the year	$ 1,066	$ 662	$ 363