Significant Accounting Policies - Additional Information (Detail)	3 Months Ended		8 Months Ended	12 Months Ended			28 Months Ended
	Dec. 31, 2018 USD ($) program $ / shares	Mar. 26, 2017 USD ($) $ / shares	Aug. 23, 2016	Dec. 31, 2018 USD ($) contract program $ / shares	Dec. 31, 2017 USD ($) $ / shares	Dec. 31, 2016 USD ($) $ / shares	Dec. 31, 2018 USD ($) program	Aug. 24, 2016	Aug. 16, 2016
Significant Accounting Policies [Line Items]
Number of contract types | contract				3
Ending backlog	$ 130,500,000,000			$ 130,500,000,000			$ 130,500,000,000
Performance obligation satisfied in previous period				2,000,000,000	$ 1,800,000,000	$ 1,400,000,000
Independent research and development costs charged to cost of sales				$ 1,300,000,000	1,200,000,000	988,000,000
Weighted average remaining contractual life, vested				3 years
Financing receivable, significant sales				$ 532,000,000	698,000,000
Gain (loss) on sale of accounts receivable				0	0
Depreciation				759,000,000	760,000,000	747,000,000
Capitalized internal-use software, net	447,000,000			447,000,000	424,000,000		447,000,000
Capitalized internal-use software accumulated amortization	2,100,000,000			2,100,000,000	2,000,000,000		2,100,000,000
Goodwill	10,769,000,000			$ 10,769,000,000	10,807,000,000	10,764,000,000	10,769,000,000
Percentage of gains and losses recognition to the extent exciding greater of plan assets or obligations				10.00%
Average future service period of employees expected to receive benefits under the plans				9 years
Time period environmental costs and recovery of environmental costs are projected over, years				20 years
Fair value of trading securities	1,300,000,000			$ 1,300,000,000	1,400,000,000		1,300,000,000
Net gains (losses) on marketable securities				(67,000,000)	150,000,000	66,000,000
Total equity method investments	1,200,000,000			1,200,000,000	1,400,000,000		1,200,000,000
Net earnings from equity method investments				119,000,000	207,000,000	443,000,000
Contracts Accounted for under Percentage of Completion
Significant Accounting Policies [Line Items]
Increase in operating profit due to profit rate adjustments				1,900,000,000	1,600,000,000	1,400,000,000
Increase in net earnings due to profit rate adjustments				$ 1,500,000,000	$ 1,100,000,000	$ 910,000,000
Increase in diluted earnings per common share due to profit rate (in dollars per share) | $ / shares				$ 5.23	$ 3.79	$ 3.00
Minimum
Significant Accounting Policies [Line Items]
Acquired finite-lived intangible assets are amortized				3 years
Minimum | Customer programs
Significant Accounting Policies [Line Items]
Acquired finite-lived intangible assets are amortized				9 years
Maximum
Significant Accounting Policies [Line Items]
Acquired finite-lived intangible assets are amortized				20 years
Maximum | Customer programs
Significant Accounting Policies [Line Items]
Acquired finite-lived intangible assets are amortized				20 years
Designated as hedges | Interest rate swaps
Significant Accounting Policies [Line Items]
Aggregate notional amount of derivatives	1,300,000,000			$ 1,300,000,000	$ 1,200,000,000		1,300,000,000
Designated as hedges | Foreign currency contracts
Significant Accounting Policies [Line Items]
Aggregate notional amount of derivatives	$ 3,500,000,000			$ 3,500,000,000	4,100,000,000		$ 3,500,000,000
Space
Significant Accounting Policies [Line Items]
Number of commercial satellite programs with performance issues | program	2			2			2
Goodwill	$ 1,585,000,000			$ 1,585,000,000	1,587,000,000	$ 1,585,000,000	$ 1,585,000,000
Net earnings from equity method investments				$ 210,000,000	205,000,000	325,000,000
Buildings | Minimum
Significant Accounting Policies [Line Items]
Property, plant and equipment, estimated life (years)				10 years
Buildings | Maximum
Significant Accounting Policies [Line Items]
Property, plant and equipment, estimated life (years)				40 years
Machinery and equipment | Minimum
Significant Accounting Policies [Line Items]
Property, plant and equipment, estimated life (years)				5 years
Machinery and equipment | Maximum
Significant Accounting Policies [Line Items]
Property, plant and equipment, estimated life (years)				15 years
Capitalized Software
Significant Accounting Policies [Line Items]
Capitalized internal-use software amortization				$ 106,000,000	123,000,000	$ 136,000,000
Capitalized Software | Minimum
Significant Accounting Policies [Line Items]
Property, plant and equipment, estimated life (years)				2 years
Capitalized Software | Maximum
Significant Accounting Policies [Line Items]
Property, plant and equipment, estimated life (years)				6 years
AWE Management Limited
Significant Accounting Policies [Line Items]
Ownership interest percentage owned immediately before acquisition								33.00%	33.00%
Ownership interest percentage owned subsequent acquisition								51.00%
Segment Concentration Risk | Net Sales | AWE Management Limited | Space
Significant Accounting Policies [Line Items]
Concentration percentage				100.00%			100.00%
Segment Concentration Risk | Operating profit | AWE Management Limited | Space
Significant Accounting Policies [Line Items]
Concentration percentage				51.00%		51.00%	51.00%
Equity Method Investment Risk | Net Sales | AWE Management Limited | Space
Significant Accounting Policies [Line Items]
Concentration percentage			0.00%
Equity Method Investment Risk | Net Earnings | AWE Management Limited | Space
Significant Accounting Policies [Line Items]
Concentration percentage			33.00%
EADGE-T
Significant Accounting Policies [Line Items]
Contract loss incurred, gross		$ 120,000,000
Contract loss incurred, after tax		$ 74,000,000
Contract loss incurred, after tax (in dollars per share) | $ / shares		$ 0.25
Commercial satellite cumulative losses on development	260,000,000			$ 260,000,000	$ 260,000,000		$ 260,000,000
LM2100
Significant Accounting Policies [Line Items]
Contract loss incurred, gross				75,000,000
Contract loss incurred, after tax				$ 56,000,000
Contract loss incurred, after tax (in dollars per share) | $ / shares				$ 0.20
Commercial satellite cumulative losses on development	380,000,000			$ 380,000,000			380,000,000
Warrior Capability Sustainment Program
Significant Accounting Policies [Line Items]
Contract loss incurred, gross				85,000,000
Contract loss incurred, after tax				$ 64,000,000
Contract loss incurred, after tax (in dollars per share) | $ / shares				$ 0.22
Commercial satellite cumulative losses on development	$ 140,000,000			$ 140,000,000			$ 140,000,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, percentage	38.00%			38.00%			38.00%
Expected time of satisfaction	12 months			12 months			12 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, percentage	66.00%			66.00%			66.00%
Expected time of satisfaction	12 months			12 months			12 months
AMMROC
Significant Accounting Policies [Line Items]
Equity method investee impairment	$ 110,000,000	$ 64,000,000
Increase in net earnings due to profit rate adjustments	$ 83,000,000	$ 40,000,000
Increase in diluted earnings per common share due to profit rate adjustments (in dollars per share) | $ / shares	$ 0.29	$ 0.14