Commitments and Contingencies (Unaudited) (Tables)

6 Months Ended

Jun. 30, 2018

Environmental Remediation Range of Future Costs [Line Items]

Environmental Remediation [Table Text Block]

The table below summarizes management’s estimate of the range of reasonably possible future costs for environmental remediation, the amount accrued within that range, and the deferred costs expected to be recoverable through overhead charges on U.S. government contracts as of June 30, 2018 and December 31, 2017:

$ in millions	Range of Reasonably Possible Future Costs(1)	Accrued Costs(2)		Deferred Costs(3)
June 30, 2018	$453 - $836	$	463	$	236
December 31, 2017	405 - 792	410		207

⁽¹⁾  Estimated remediation costs are not discounted to present value. The range of reasonably possible future costs does not take into consideration amounts expected to be recoverable through overhead charges on U.S. government contracts.

⁽²⁾ As of June 30, 2018, $155 million is recorded in other current liabilities and $308 million is recorded in other non-current liabilities.

⁽³⁾ As of June 30, 2018, $79 million is deferred in prepaid expenses and other current assets and $157 million is deferred in other non-current assets. These amounts are evaluated for recoverability on a routine basis.