Commitments and Contingencies (Tables)

3 Months Ended

Mar. 31, 2018

Commitments and Contingencies Disclosure [Abstract]

Summary of Environmental Reserve Activity

A summary of the Company’s environmental reserve activity is shown below:

	Aerojet Rocketdyne- Sacramento			Aerojet Rocketdyne- BPOU			Other Aerojet Rocketdyne Sites			Total Aerojet Rocketdyne			Other			Total Environmental Reserve
	(In millions)
December 31, 2017	$	206.5		$	116.4		$	13.7		$	336.6		$	4.8		$	341.4
Additions	5.1			0.4			0.1			5.6			(0.1		)	5.5
Expenditures	(3.1		)	(4.5		)	(0.7		)	(8.3		)	(0.2		)	(8.5		)
March 31, 2018	$	208.5		$	112.3		$	13.1		$	333.9		$	4.5		$	338.4

Summary of Northrop Agreement Activity

A summary of the Northrop Agreement activity is shown below (in millions):

Total reimbursable costs under the Northrop Agreement	$	189.7
Amount reimbursed to the Company through March 31, 2018	(126.7		)
Potential future cost reimbursements available	$	63.0

Summary of Financial Information for the Impact of Environmental Reserves and Recoveries

Summarized financial information for the impact of environmental reserves and recoveries to the unaudited condensed consolidated statements of operations is set forth below:

	Three months ended March 31,
	2018		2017
	(In millions)
Estimated recoverable amounts under U.S. government contracts	$	4.1	$	3.9
Expense to unaudited condensed consolidated statement of operations	1.4		0.8
Total environmental reserve adjustments	$	5.5	$	4.7