Business Acquisition (Unaudited) (Details 3) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2018	Jun. 30, 2018
Business Acquisition [Line Items]
Pro forma sales	$ 8,078.0	$ 16,078.0
Pro forma net earnings	$ 882.0	$ 1,796.0
Pro forma diluted earnings per share	$ 5.03	$ 10.24
Pro Forma Adjustments, Orbital ATK intercompany sales elimination	$ (33.0)	$ (80.0)
Pro Forma Adjustments, Elimination of nonrecurring transaction costs	64.0	71.0
Pro Forma Adjustments, Additional depreciation expense, net of removal of historical depreciation	(5.0)	(11.0)
Pro Forma Adjustments, Additional amortization expense, net of removal of historical amortization expense	(48.0)	(114.0)
Pro Forma Adjustments, Elimination of Orbital ATK’s amortization on net actuarial losses and prior service costs and pension/post-retirement costs	20.0	51.0
Income Tax Effects of Pro Forma Adjustments	$ (7.0)	$ 0.4

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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The pro forma diluted net income per share for a period as if the business combination or combinations had been completed at the beginning of a period.

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The pro forma net Income or Loss for the period as if the business combination or combinations had been completed at the beginning of a period.

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The pro forma revenue for a period as if the business combination or combinations had been completed at the beginning of the period.

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